APPEALED FROM: Motor Accidents Insurance Board v Lester [2016] TASSC 2

Torts - Negligence - Essentials of action for negligence - Standard of care - Generally - Standard to be assessed by reference to a reasonable person in the position of, and with the knowledge and capacities of the defendant - Absence of evidence establishing that standard - Defendant acting in accordance with common industry practice - Standard of care not to be assessed on the basis of hindsight nor expertise in excess of that possessed by defendant - Breach of duty not established

Dovuro Pty Ltd v Wilkins [2003] HCA 51, 215 CLR 317; Shoalhaven City Council v Pender [2013] NSWCA 210; State of New South Wales v Briggs [2016] NSWCA 344 Vairy v Wyong Shire Council [2005] HCA 62, 223 CLR 422 Wilson v Nilepac Pty Ltd [2011] NSWCA 63, cited.

Torts - Negligence - Essentials of action for negligence - Damage - Causation - Other Cases - Factual causation to be established by reference to the "but for" test - Plaintiff unable to establish actual cause of escape of cattle from paddock and that the escape and consequent injury would not have occurred but for the negligence of the defendants - Factual causation not proved.

Adeels Palace Pty Ltd v Moubarak [2009] HCA 48, 239 CLR 420; Strong v Woolworths Ltd [2012] HCA 5, 246 CLR 182 Langmaid v Dobsons Vegetable Machinery Pty Ltd [2014] TASFC 6, 24 Tas R 18, cited.

Torts - Negligence - Road accident cases - Liability of persons having charge of animals - Driver injured in collision with steers on a highway which had escaped from adjoining farming property - Motor Accidents Insurance Board paid scheduled benefits - Proceedings by Board pursuant to Motor Accidents (Liabilities and Compensation) Act 1973, s 28C, to recover scheduled benefits paid and to be paid from non-indemnifiable persons.

Motor Accidents (Liabilities and Compensation) Act 1973 (Tas), s 28C.

Judgment Number: [2017] TASFC 6

3 Judgment in the action for the defendants against the plaintiff.

1. These two appeals concern a gudgeon pin that became detached from a gatepost beside Back Line Road, near Smithton, one night in June 2008. As a result, some cattle escaped from a farming property onto Back Line Road. Some strayed onto the Bass Highway. A motorist named Mitchell House drove into one of those cattle and was catastrophically injured. The Motor Accidents Insurance Board ("MAIB") paid an enormous amount to him and for his benefit by way of "scheduled benefits", pursuant to the Motor Accidents (Liabilities and Compensation) Act 1973 ("the Act"). The MAIB sued a couple named Lester and a company named Circular Head Fencing Pty Ltd ("CHFPL"), seeking reimbursement of the monies it had paid out. Mr and Mrs Lester ("the Lesters") owned the cattle and the land from which they escaped. CHFPL, as a contractor engaged by the Lesters, had constructed a new boundary fence along the frontage of their property on Back Line Road. That fence included the gateway through which the cattle escaped. The gate was designed to be secured by means of a gudgeon pin and a chain to the northern gatepost.
2. The MAIB's claim against the other parties was made pursuant to s 28C(2)(a) of the Act. That provision reads as follows:

"(2) The Board may recover from a non-indemnifiable person a scheduled benefit paid to any other person in respect of personal injury if the circumstances of the motor accident which resulted in the personal injury -

(a) created a liability in the non-indemnifiable person to pay damages ...".

1. For the purposes of the Act, CHFPL and the Lesters are non-indemnifiable persons. The MAIB sought to recover the amount of the scheduled benefits from them on the basis that they were liable to pay damages in respect of Mr House's injuries as a result of their negligence.
2. The MAIB's action went to trial before Tennent J. Her Honour held that the injuries suffered by Mr House resulted from negligence on the part of both the Lesters and CHFPL; that the Lesters should bear 65% of the liability to the MAIB; and that CHFPL should bear 35%: Motor Accidents Insurance Board v Lester [2016] TASSC 2. From that judgment, CHFPL and the Lesters have separately appealed. CHFPL contends that the learned trial judge erred in concluding that it was negligent. The Lesters contend that she erred in holding that they were negligent, and in apportioning liability as she did. The two appeals were heard together.

1. CHFPL is a company that was formed and controlled by a man named Andrew Blizzard. He installed a new fence for the Lesters along the eastern side of Back Line Road between 2 October 2007 and 9 October 2007. The previous fence had been removed by another contractor. Mr Blizzard gave evidence at the trial.
2. His evidence was to the following effect. He was required to construct a fence with four strands of wire. The top strand and the third strand were electrified. The second and fourth were not. They were plain earth wires. The Lesters supplied all the materials, including a steel gate for the relevant gateway. He installed that gate so that the southern gatepost was the hinge post and the northern gatepost was the latch post. At the position of the latch post there was an existing hole and an existing strainer post, which he re-used. Once that strainer post was in the ground, he was not happy with how solid it was. He therefore took a six-foot running post and rammed that into some solid ground beside it. He lashed the two posts together. The strainer post was vertical. The Lesters told him that he could use fittings from a bucket in their shed. He looked in the bucket and found a gudgeon pin that "would do the job". He had no concern about that gudgeon pin at any stage. He drilled a pilot hole into the gatepost. That hole was no more than 8 mm in diameter. He hit the gudeon pin with a hammer at first to get the first lot of thread into the pilot hole. Then he wound the gudgeon pin in with a shifting spanner. The gudgeon pin "took a bite and wound in past the thread". He used some force to wind it in. He wound it in until there was no thread showing. He installed the gudgeon pin parallel with the fence because the chain was too short for him to install it in a different position. The chain was a good snug fit. None of that evidence was challenged or contradicted.
3. Michael Lester and his son, Matthew Lester, both gave evidence. Michael Lester is one of the owners. Matthew Lester was employed by them as their farm manager.
4. Matthew Lester gave evidence to the following effect. There was a bucket in the shed that contained gudgeon pins, latches, hinges and so forth. He told Mr Blizzard that in that bucket he might be able to find something suitable to swing the gate from, and some pins. He took no role in the construction of the fence. He visited Back Line Road while Mr Blizzard was working there. At a guess, he did that two or three times. He had no complaint with Mr Blizzard's workmanship. He used that gate about five times or about once per month before the accident. He did not notice anything out of the ordinary. After the accident, the fence wires had been tightened and the fence looked normal. The gudgeon pin was back in its hole. Wire was holding the gate in position. He carried out some repairs between one month and six months after the accident. He installed a longer chain and a new pin. He installed the pin in a different position, further around the gatepost. He put the old gudgeon pin back into the bucket in the shed.
5. Michael Lester gave evidence to the following effect. He was happy with the work of CHFPL. After the new fence was installed, he used the gate in question on at least two occasions. The last time was about a week before the accident. The previous time was about a month before that. When he used the gate about a week before the accident, the chain was taut, and there was not a lot of free play. The chain came off the gudgeon pin as usual. He did not notice anything wrong with the post. He was on King Island at the time of the accident. He came back a couple of days after it. He noticed that the post was leaning slightly towards the Bass Highway (that is, away from the gate). The nearby strainer posts remained vertical.
6. On the night of the accident a neighbour named Gregory Ralston rounded up some of the Lesters' escaped cattle, drove them back through the open gate, closed it, and secured it. He gave evidence to the following effect. He saw mud and flattened grass which indicated that a number of cattle had escaped through that gate. The gudgeon pin and chain were hanging down to the ground, still connected to one another. The gate had opened outwards, towards Back Line Road. He swung the gate through the gateway so that it opened inwards before driving the cattle back into the paddock. He closed the gate, and put the gudgeon pin back into its hole. He had no difficulty doing that. The gudgeon pin was loose. He pushed it in and pulled it back out again, using only his hands. He did not have a hammer with him. Because the gudgeon pin was loose, he used some wire to secure the gate.
7. As a result of Matthew Lester having returned the gudgeon pin in question to the bucket in the shed, it was not possible for anyone to identify any particular gudgeon pin as the one that had become detached from the gatepost. However Mr Ralston was shown two gudgeon pins and asked to identify the one that better resembled the gudgeon pin that he saw on the night. He identified a gudgeon pin that subsequently became exhibit P26. Each of the two gudgeon pins has an internal thread, as distinct from a raised thread. The thread on exhibit P26 winds around the shaft of the pin eight times. The groove of the internal thread is shallow, and narrower than the section between the grooves.
8. Some photos taken on the day after the accident were tendered at the trial. They show that the gatepost was not vertical, but leaning slightly away from the gate. It is just discernible in the photos that a little of the thread of the gudgeon pin is visible. That suggests that the relative positions of the gate and the post were then such that, with the chain from the gate attached to the gudgeon pin, that pin could no longer be inserted into its hole to such an extent that all of its thread disappeared from view.

1. The MAIB adduced expert opinion evidence from three witnesses. This evidence was essentially concerned with the gudgeon pin and chain as a means of securing the escape gate. The said experts and a brief summary of aspects of the evidence are as follows:

1. Mr Armstrong is an agricultural consultant who has substantial experience in practice, although no formal qualifications, in relation to farm fencing and gates. He inspected the gate and latching mechanism in December 2008. He conducted some further testing (which was filmed) in January 2009 and made a further inspection in February 2009. Mr Armstrong's evidence included two written reports.
2. It is clear from Mr Armstrong's evidence, that, at the time of his inspection of the gate in December 2008, the gudgeon pin was very loose in the hole in which it was inserted. He was able to easily remove the pin by gently wobbling the gate, and able to push it back in with his hand. At the date of his examination in March 2009, the posts on each side of the gate were leaning at an angle away from the gate.
3. Mr Armstrong confirmed that a gudgeon pin and chain was a common method employed on Tasmanian farms at the time relevant to these proceedings, for the purpose of securing boundary gates. He conducted a survey of gates with access to the Bass Highway in the area in question on 29 December 2008. He recorded that "Of 27 gates with access to the Bass Highway, 16 have similar security mechanisms (chain a [sic] with ring and gudgeon)." However, he also noted that "a number of gates also had additional security, such as a second chain and padlock and/or an offset electric wire."
4. In the same report, Mr Armstrong also concluded:

(a) The gudgeon pin and chain system "represents the minimum security requirement for a gate in this situation. It is highly unlikely a gate with this securing mechanism properly installed could be opened by cattle."

(b) "... that cattle pushed against the gate causing the gudgeon to come free from the post allowing the gate swing open". He noted that "cattle commonly push and rub against gates".

(c) The pressure on the gate caused the gudgeon, which was not secured tightly in the hole, to come out of the hole.

1. Of course, Mr Armstrong's conclusions concerning what actually happened on the night in question simply represent his opinion as to what may have caused the gate to come open. There was no direct evidence that cattle had actually rubbed against or placed any form of pressure on the gate. His opinion concerning the looseness of the gudgeon pin in the post seems to have been based entirely on his inspection of the gudgeon and the hole into which it was inserted, conducted for the first time in December 2008.
2. Mr Armstrong's evidence was not subject to any significant challenge during the course of cross-examination.

1. Mr Carroll is a structural engineer. In 2014, he conducted a structural engineering appraisal of the latching mechanism used on the escape gate. His conclusions were expressed in two reports, each placed in evidence. He also provided oral testimony.
2. Mr Carroll examined the gate and post in question. He measured a hole which may have been the hole into which the gudgeon pin was originally inserted, and viewed a gudgeon pin which he concluded was similar and "almost certainly the same pin" as that removed after the accident. The pin he inspected was that identified by Mr Armstrong as the one that he inspected in December 2008. It was a reasonable inference that that pin was the one inserted in the post as part of the securing mechanism of the "escape gate" on the night in question.
3. Mr Carroll's evidence and conclusions will be discussed in greater detail later in these reasons. However, his fundamental conclusion is that the "latch mechanism" was "defective from an engineering perspective". The gudgeon and chain were not sufficient to resist the forces that might be imparted by cattle rubbing or leaning against the gate, and that given that the gate provided potential access to a busy highway, alternative methods of securing the gate ought to have been employed.

1. Ms Gaffney's evidence consisted of a report placed in evidence by the MAIB. It would seem that the report had been prepared and served on behalf of CHFPL, but was placed in evidence by the MAIB pursuant to the Supreme Court Rules 2000, r 517. There was no requirement for cross-examination, and she did not provide oral testimony. It was an agreed position that her evidence was admissible only against CHFPL.
2. Ms Gaffney is described in her report as a "mechanical and forensic engineer". Her investigations were also conducted in 2014. They included inspections and analysis of the gate and post, and the gudgeon pin referred to above. Her conclusions will also be discussed in more detail later in these reasons, but can be summarised as follows:

(a) The maximum pull out resistance of the gudgeon pin, even if inserted as securely as possible, was approximately 95kg. This is well less than the force which could be exerted by a single cow "determined to escape".

(b) The force required to break the chain is approximately 199 kg. Accordingly, a 600 kg cow could break the chain by exerting a pushing force equivalent to one third of its mass. Again, a cow "determined to escape" could exert that amount of force.

(c) The gudgeon pin, even if inserted as securely as possible, will pull out of the post before the chain is broken.

1. Ms Gaffney's opinion relating to the pull out resistance of the gudgeon pin was based on her inspection and analysis of the pin and its thread. She noted that "although the subject gudgeon is threaded, the threads are recessed such that their external diameter is flush with the shank diameter". Accordingly, it is "not accurately modelled as a threaded screw" and the threads "do virtually nil to restrict the pull out force as they are not oriented in a way to provide a reaction force against the wood".

1. Professor Phillips' evidence was adduced by the Lesters. He had expertise in cattle husbandry and welfare, which seems to have been accepted as extending to animal behaviour. His evidence was largely related to the suggested possibility of a stampede. However, he did express some conclusions of wider relevance, including:

(a) Cattle are known to rub against solid objects as a means of cleaning their skin. Hence, they might rub against a gate but it is more probable that they would rub against a fence post.

(b) Positioning an electric fence within a gate is not normal practice, as it creates too much difficulty in opening the gate to allow cattle to pass through. Farm gates are, therefore, usually constructed to be cattle proof without use of an electric offset wire.

1. The learned trial judge made findings to the following effect, none of which are challenged in these appeals:
   • The animal involved in the collision with Mr House's vehicle belonged to the Lesters.
   • It had escaped through the gate in question, on the night that the accident occurred.
   • It was able to escape because the gate had come open. This had occurred because the gudgeon pin had come out of the gate post, when it was still attached to the chain which was meant to secure the gate.
   • The pin had not been forced from the gate as a result of the stampede of cattle. No stampede occurred.
2. The trial judge's findings of negligence against each appellant were in essence based on the findings contained in the following paragraphs, which although they expressly relate to the case against the Lesters, were also applied by her Honour in respect of the case against CHFPL:

"[145] In my view, it is unnecessary to determine whether pressure on the post, gate or adjoining fencing caused the strainer post to move and the pin to fall out, or whether the gudgeon pin simply fell out as a result of some pressure applied by cattle to the gate or post. The above factors and others lead me to be positively satisfied that the gudgeon pin was, prior to the escape, loosely fitting such that even relatively minimal pressure allowed it to be pulled out and thus the gate to open. Those further factors are:

• the type of thread on the gudgeon pin and that it was worn.
• that the nature of the thread would not have provided sufficient friction to prevent it coming out even with a relatively low level of force.
• the size of the steers in the paddock with the gate.
• that those steers were, certainly late on the afternoon of 25 June, being fed somewhere near the gate and that feed was expected to last them at least overnight, thus placing the steers in the vicinity of the gate rather than elsewhere in the paddock.
• that there was no evidence of the gudgeon pin having been 'torn out'.
• as a matter of fact, the gudgeon pin was able to be manually pushed in and pulled out easily by Mr Ralston and Mr Armstrong. Mr Armstrong's 'tests', while not particularly scientific, did demonstrate how easily the gudgeon pin could come out of the fence post. The fact that it could come out in the manner it did clearly demonstrates it was loosely fitting at the time of the accident.
• that the strainer post had been installed in an area which even Blizzard acknowledged required him to put an extra post in to provide some security for it.

I do not, in my view, need to determine precisely what the level of force was which was applied to the gate, fencing or posts. The factors I have identified show that something caused the strainer post to move slightly away from the vertical. That was sufficient to pull the gudgeon pin out of the strainer post because of the tightness of the chain, the deficiency in the design of the gudgeon pin and the level of wear, and the manner in which it had been installed.

[146] It is implicit in the above that I do not accept the evidence given by Blizzard as to the state of the gudgeon pin he used, that is its fitness for purpose, and the process he undertook to ensure the pin was securely installed."

1. It is apparent that the basic premise for the trial judge's reasoning, as explained in these paragraphs, is the primary finding that prior to the escape, the gudgeon pin was "loosely fitting such that even relatively minimal pressure allowed it to be pulled out and thus the gate to open". On the basis of this single finding, her Honour reasoned as follows:

(a) The looseness of the gudgeon pin supported the conclusion that there was a "deficiency in the design of the gudgeon pin, the gudgeon pin was worn, and it had been installed in a manner which left it loose in the post". As will be discussed in more detail later in these reasons, these consequential findings, in particular that the gudgeon pin was not fit for purpose, and had been inadequately inserted into the post by Mr Blizzard, underpinned her Honour's finding of negligence against each of the appellants. In particular:

(i) The Lesters were negligent because they did not check that the materials supplied to Mr Blizzard, in particular the gudgeon pin, was fit for purpose, and further, they did not take reasonable steps to check that that the pin was tight in the post.

(ii) CHFPL was negligent because, as an experienced fencing contractor, Mr Blizzard used a gudgeon pin that was not fit for purpose and did not advise the Lesters of this and advise them to purchase a more appropriate gudgeon pin.

(b) In relation to the question of causation, her Honour found that for some unidentified reason, the strainer post had moved slightly away from the vertical. The chain of causation, in accordance with her Honour's findings, was that because the gudgeon pin was loose, upon the post moving away from the vertical, it became detached from the post and hence the gate was opened and the cattle escaped.

1. It was not argued by any of the appellants that any of them did not owe a duty to road users to exercise reasonable care with respect to the potential escape of cattle through the gate. It was clear, in any event, that such a duty did arise in the case of each of them. The gate was located on a boundary between the property and Back Line Road, which could expect vehicular traffic from time to time. Further, the gate was only a short distance from the intersection of Back Line Road and the Bass Highway. It was clearly foreseeable that if the gate was not secured in a way which prevented the escape of cattle, then cattle, upon escape, could easily wander onto the busy Bass Highway, resulting in an accident of the type which caused Mr House's injuries.
2. The Lesters conceded the existence of the duty at trial. It was conceded that their duty related to the construction and maintenance of boundary fences and that it was non-delegable. However, the Lesters claimed indemnity from CHFPL in the event that the causation of Mr House's injuries related to defects in respect of the construction by CHFPL of the fence, which were not detectable upon reasonable inspection.
3. CHFPL also accepted at trial (although not on the pleadings) that it had a duty to use reasonable care in respect of the construction of the fence, and that that duty was owed to road users in the position of Mr House. It was conceded that this duty included the obligation to take reasonable care to construct the gate in a manner which would prevent the escape of cattle.
4. The arguments of the appellants reflected in the grounds of appeal and submissions on appeal can be summarised as follows:

(a) That her Honour's findings that the gudgeon pin was, prior to the escape, "loosely fitting such that even relatively minimal pressure allowed it to be pulled out and thus the gate to open" and concerning the failure of Mr Blizzard to adequately install the gudgeon pin, hence leaving it loose in the gatepost and able to be easily withdrawn, were not justified or open on the evidence.

(b) That her Honour failed to make a finding as to what caused the gudgeon pin to become detached from the gatepost. The appellants argue that this finding was necessary, irrespective of whether or not, and if so, the extent to which the pin was loose in the gatepost, because it was crucial to a consideration of whether it had been proved that any of the appellants were in breach of their respective duty of care, and, further, whether any such breach caused the gate to come open, leading to the escape of cattle and the consequent injuries to Mr House.

(c) That her Honour did not, and could not on the evidence, conclude that the manner of installation of the gudgeon pin as a means of securing the gate fell below what was expected of any of the appellants on the basis of their duty to exercise reasonable care in that regard.

(d) That her Honour did not, and on the evidence could not, conclude that had the gudgeon pin been more securely inserted to the post, at least to a standard consistent with the exercise of reasonable care, that it would not, in any event, have been dislodged. Hence, it is argued the MAIB did not establish that but for the departure from the standard of reasonable care in respect of the insertion of the gudgeon pin and the securing of the gate by any of the appellants, the cattle would not have escaped through the gate, and the injuries to Mr House would not have occurred. This argument relates to the requirement that the MAIB prove that the breach of duty was a necessary element of the occurrence of harm, pursuant to s 13(1)(a) of the Civil Liability Act 2002.

(e) CHFPL argues that even if the MAIB has proved factual causation, it is not appropriate for the scope of liability of CHFPL to extend to the harm caused to Mr House.

(f) The Lesters also contend that her Honour erred in respect of her apportionment of liability between the appellants.

1. The MAIB's submissions can be summarised as follows:

(a) Her Honour's conclusion that the gudgeon pin became detached from the post hence allowing cattle to escape, because it had been inadequately installed and hence was loose, was supported and justified by the evidence.

(b) That, in any event, the means selected by CHFPL to secure the gate, that is by gudgeon pin and chain, was an inadequate method by which to secure the gate against the escape of cattle. This is particularly so given the selection of a gudgeon with an internal thread. The MAIB asserted that compliance with the duty of all appellants required the gate to be secured by alternative means. The MAIB argues that the failure to use an adequate means to secure the gate amounted to a breach of a duty of care by each appellant.

1. Because the findings concerning the pin being loose in the post, the adequacy of its insertion by Mr Blizzard and the fitness for purpose of the pin were all crucial to the trial judge's reasoning process in respect of the liability of all appellants, and have been challenged on this appeal, it is appropriate to first examine whether the trial judge erred in making these findings before considering the ultimate challenge to the findings of breach of duty and causation.

Was the gudgeon pin loose immediately prior to the escape of the cattle?

1. There was no direct evidence that the pin was loose in the post prior to becoming dislodged. Her Honour's finding in this regard was an inference which she drew from the evidence. The factors upon which her Honour relied in order to draw the said inference can be summarised as follows:

(b) According to photographs taken on the day after the escape, the gudgeon pin could not, with the chain attached, be screwed into the strainer post so that there was no thread showing.

(c) The gudgeon pin was unfit for its purpose. Her Honour relied on her conclusion that the thread was worn and, in any event, that the recessed nature of the thread meant that it could not provide sufficient resistance to prevent it coming out of the post even with a low level of force.

(d) The presence of steers in the paddock that night.

(e) A lack of evidence that the gudgeon pin had been "torn out".

(f) That the following day Mr Ralston, and then some months later Mr Armstrong, both found the gudgeon pin to be loose in the hole and able to be easily manually inserted and pulled out.

1. An examination of the evidence reveals a number of errors in her Honour's reasoning in respect of these factual conclusions.

1. Her Honour concluded that Mr Blizzard was either untruthful about having screwed the gudgeon pin in so that no thread was showing, or had installed the gudgeon pin and used materials which allowed it to "simply pull out" when there was movement of the strainer post away from the vertical. Her Honour's justification for these observations is based on the evidence from photographs taken the day after the escape which show that the gudgeon pin could not, with chain attached, be inserted into the strainer post so that there was no thread showing, and further that when inserted in the strainer post at all, the chain is taut to the point where it could not be lifted off the pin without difficulty. Her Honour contrasted this situation to the evidence of the Lesters which indicated that shortly before the night of the escape, the chain could be lifted off the pin and placed back on without difficulty.
2. There are a number of difficulties in relation to this reasoning. Firstly, the truthfulness and reliability of Mr Blizzard's evidence about the steps he took to insert the gudgeon pin in the post was not challenged during the trial, either in cross-examination or by the trial judge. Further, there was no direct evidence which contradicted his evidence in relation to these aspects of the matter. Secondly, all that is logically demonstrated by the inability, after dislodgement, to reinsert the gudgeon pin into the post, either to the extent of its thread or at all, without causing the chain to be so tight that it cannot be removed, is that the post had moved further away from the gate than its position at the time the gate was last used. Her Honour recorded the evidence of Michael Lester that he had used the gate about one week before the accident and that, although there was not a lot of free play in the chain, it had come off the pin normally. There was no challenge to or direct contradiction of this evidence and it was not rejected by the trial judge. It was, therefore, reasonable to conclude that, in all probability, the movement of the post occurred at the time of or after the detachment of the gudgeon pin. If it had occurred before then, the length of the chain would not have permitted it to remain attached to the gudgeon pin. However, the chain was attached to the dislodged gudgeon when it was found on the day after the escape. That circumstance strongly supports the conclusion that prior to the gudgeon pin becoming detached from the post, the post had been closer to the gate.
3. Counsel for the MAIB submitted that the evidence supported an inference that the movement of the strainer post towards the fence line had occurred gradually over time. He relied on evidence from Mr Armstrong that the hinge post had also moved a similar distance, in the opposite direction. He submitted that the corresponding movement of both posts was consistent with that movement resulting from force exerted by the tension of the fence wires, and the softness of the ground into which the posts had been embedded. However, this inference is not justified by the evidence. Mr Armstrong states that he is "unable to state when the strainer pulled away from the gate". Further, the reasoning already discussed concerning the observations of Michael Lester one week before the escape, and the fact that the chain was found attached to the gudgeon after the escape, contradict such a conclusion.
4. However, there was no reasonable basis to conclude that it was more probable than not that the movement of the post had coincided with the detachment of the gudgeon pin from the post, as opposed to having occurred after dislodgement and the consequent escape. It was equally consistent with the objective facts that the post had moved after the detachment of the gudgeon pin. In the absence of a finding as to the actual circumstances in which the gudgeon pin became detached from the post, this possibility could not be excluded as the least probable alternative.
5. Accordingly, it was not open to reason that because the pin could not be fully inserted to the full extent of the thread after the accident, that it must have been not fully inserted by Mr Blizzard some months before. If the post had moved away from the vertical at or after the dislodgment, then that simple fact alone explains the subsequent inability to reinsert the pin fully, and is consistent with a pin inserted fully into the post before dislodgement.

1. There was no direct evidence that the gudgeon pin was loose in the post immediately prior to the escape of the cattle. On the contrary, the unchallenged evidence of Michael and Matthew Lester was that they had been through the gate on a number of occasions in the months leading up to the escape and had not observed any difficulty with the mechanism, including the firmness of the gudgeon pin in the post, or the length of the chain. Michael Lester's evidence was that if he had observed any such difficulty, he would have attended to it immediately. Her Honour did not reject this evidence. Indeed, she seemed to accept the evidence of the Lesters as to the state of the securing mechanism prior to the escape in her reasoning that the post had moved during the course of the escape.

Evidence of Mr Ralston, Mr Armstrong and Ms Gaffney

1. The fact that the gudgeon pin was found by Mr Ralston the next day, and Mr Armstrong some months after the accident, to be loose in the hole, did not provide support for an inference that it had been equally loose immediately prior to the escape of the cattle. Her Honour observed that there was no evidence that the gudgeon pin had been "torn out", and, of course, found that there had been no stampede. However, as was observed by Ms Gaffney in her report:

"1 In the absence of post-incident microscopic testing, it is not possible to scientifically determine the strength of the gudgeon pin within the post as it existed on the date of incident. If microscopic dissection of the subject gudgeon pin and post had been conducted immediately following the incident, it would possibly reveal evidence indicating whether the pin was forcefully removed or not. However, forensic evidence that would have been present (or not present) post-incident was destroyed each time the pin was inserted and removed."

1. Her Honour did not make any finding to the contrary of this observation, and there was no other evidence that would contradict the observation. Accordingly, it was simply not open to reason that because the gudgeon pin was loose in the hole after the escape, it must have been loose in the hole before the escape. It is an inescapable observation that had the pin been dislodged from the hole by a force sufficient to achieve that result, it must necessarily have overcome and taken with it whatever wood had engaged with the thread. This must be the case irrespective of the degree of pre-dislodgment resistance.

Finding that minimal force could dislodge the gudgeon pin

1. The most cogent reason as to why it was not open to her Honour to reason that the pin was loose in the post immediately prior to the escape was that that conclusion was almost entirely based on her Honour's observation that "even relatively minimal pressure allowed it to be pulled out and thus the gate to open". However, her Honour made no finding as to the nature or extent of the force applied to the gudgeon pin on the night in question. The reasoning was therefore somewhat circular. Her Honour reasoned that because the gudgeon pin was loose in the post, it could be extracted with minimal force, and, further, that because minimal force was able to dislodge it, it must have been loose in the post. However, there was no direct evidence as to what force was applied to the gate or the post, and hence to the gudgeon pin, and her Honour made no finding in that regard. If a finding was available that only minimal force had been applied to the pin on the night in question, then it may have been possible to reason from that finding that the pin was loose in the post and hence was either inherently deficient or had not been inserted properly. However, without such a finding, it was equally open that a large degree of force had been applied, one which was sufficient to pull the gudgeon pin from the post, irrespective of how firmly it was then attached.
2. A key piece of evidence relating to this question is the unchallenged expert evidence concerning the maximum pull out resistance of a gudgeon pin with recessed thread. Ms Gaffney calculated the pull out force of the gudgeon pin at 930N (approximately 95 kg), on the assumption that the pin was embedded 50mm and no pilot hole was drilled prior to insertion of the latch hook. She calculated the force required to snap the chain at 199 kg. On the basis of these calculations, she concluded that even if the gudgeon pin had been inserted to the full extent of the thread (50 mm) with no pilot hole, thereby ensuring maximum resistance against the internal thread, the gudgeon pin would pull from the post before the chain snapped. Mr Carroll had calculated a somewhat higher pull out load but he agreed with Ms Gaffney that the pin would be pulled from the hole before the chain snapped.
3. Mr Blizzard's evidence was that he had inserted the pin to the full extent of the thread and had drilled a small pilot hole. As Mr Carroll noted, the logical conclusion from this evidence is that the force needed to pull out the pin was somewhat less than the maximum pull out force calculated by him and Ms Gaffney. Accordingly, the force actually needed to pull out the pin, even inserted in the manner described by Mr Blizzard, was something less than 95 kg.
4. According to both Mr Carroll and Ms Gaffney, a reasonable assessment of the mass of a single cow was 600 kg. A single animal of that mass, essentially immobile but exerting a load against the gate, for example by rubbing on it or leaning against it, could impart a force of approximately 75 to 100% of its mass, which would equate to between 450 and 600 kg. It is apparent therefore that a single cow rubbing against or leaning against the gate would impart a force well in excess of that required to force the gudgeon pin from the post, even if the gudgeon pin was inserted correctly.

1. It follows that it was not open, without identifying the force which had actually been applied to the gate, to reason from the fact that the gudgeon pin had become detached from the gate, that the force must have been minimal, and the gudgeon pin not correctly installed and/or loose within the post. A force far greater than the minimum required to remove the gudgeon pin could have been applied simply by one or more animals rubbing themselves or leaning against the gate. A stampede was not required to dislodge the gudgeon pin. The fact that the chain was not broken says nothing about the force that was actually applied, because the gudgeon pin would have come away from the post before the chain snapped in any event.

The finding that the gudgeon pin was not fit for purpose

1. Her Honour found that there was "a deficiency in the design of the gudgeon pin" in that it "had a design that would not hold against even minimal pressure, and, in any event had little thread". In the light of the expert engineering evidence discussed above, this finding would seem to be justified. As Mr Carroll, in his report, said:

"The latch mechanism as devised and installed would never have been sufficient to consistently resist the force exerted by cattle rubbing against the gate which the mechanism was intended to secure."

1. Her Honour concentrated on the adequacy of the gudgeon pin itself. However, as is apparent from the opinion expressed by the experts already discussed, and as was expressly stated by Ms Gaffney, even if it was possible to rigidly attach a gudgeon so as to resist the pressure exerted by a cow rubbing against the gate (for example, by use of a gudgeon with an external thread), the chain link would have failed at 1.95Kn (199 kg). This is still well below the force which could be exerted by a single cow leaning or rubbing itself against the gate.
2. It is true that Mr Armstrong expressed an opinion that a correctly installed gudgeon pin and chain would prevent cattle forcing the gate open. However, Mr Armstrong does not have expert engineering qualifications, and expressed his opinion solely on the basis of his general experience as an agricultural consultant, who has seen gates secured in this way on many occasions. There was no challenge to the expert qualifications of Ms Gaffney and Mr Carroll, nor any challenge to their evidence in respect of this question.
3. The trial judge's reasoning included a finding that the pin actually used was "worn". Again in the light of the implications of the expert opinion, whether the pin was worn or not would seem to be of little significance. The only available conclusion in the light of the said expert opinion is that a gate secured by a gudgeon pin, with recessed thread and chain, was never going to be adequate to withstand the pressure that might be applied by even one animal leaning or rubbing against the gate. In this sense, the finding that the gudgeon pin was not fit for purpose was justified. However, this finding, of itself, for the reasons discussed below, was not able to support a finding of liability against any of the appellants.

1. The trial judge's findings that the gudgeon pin was, immediately prior to the escape of the cattle, "loosely fitting such that even relatively minimal pressure allowed it to be pulled out", and the related finding that there was "a deficiency in the design of the gudgeon pin", and that it was not fit for purpose, were crucial to her findings of negligence against each appellant. As noted above, in relation to the Lesters, her Honour was satisfied that they were negligent because they did not check that the materials supplied to Mr Blizzard, in particular the gudgeon pin, were fit for purpose, and secondly that given her Honour's findings that the gudgeon pin was loose to the point that it could be easily pushed in and out, immediately prior to the escape, they had not taken reasonable steps to check that it was tight, and had they checked they would have discovered that it was loose. In relation to CHFPL, her Honour found that as an experienced fencing contractor, Mr Blizzard was required to determine that the gudgeon pin was fit for purpose and that it would be suitable and secure enough to hold the type of cattle the Lesters had. Therefore, he was negligent because he used a gudgeon pin that was not able to hold against even minimal pressure and did not advise the Lesters of this and require them to purchase a more appropriate gudgeon pin.
2. Her Honour rejected the position that the appellants were negligent on any other substantive basis. For example, she was not satisfied that it had been shown that the appellants were negligent for not using a different securing system, for example, a chain wrapped around the post and linked by a locked padlock, or an electric fence being placed alongside the gate to deter cattle from approaching. Her Honour did not find that any other aspect of the chain and pin system was inadequate. She was not satisfied that a "new or near new" gudgeon pin would have resolved the problem.
3. Because it was not open to the learned trial judge to find that the gudgeon pin was loose in the post immediately prior to the escape, her findings of negligence against each appellant arising from this finding cannot stand. In particular, her Honour's findings that Mr Blizzard did not properly install the gudgeon pin, and that the Lesters should have discovered that it was loose prior to the escape, were not open. However, as has been noted, her Honour's finding that the gudgeon pin was not fit for purpose, because it was never going to be able to withstand force capable of being applied by an animal or animals, was open. Further, although this was not a matter directly addressed by the trial judge, it is clear, in the light of the expert evidence and with the benefit of the hindsight provided by that evidence, that a securing system which relied on a gudgeon pin with recessed thread and chain, was also not capable of withstanding such pressure. The question which, therefore, arises is whether her Honour's finding concerning the fitness for purpose of the pin, and the related conclusion in respect of the adequacy of the chain and pin system, is sufficient to justify the trial judge's ultimate conclusion that each appellant was in breach of their duty of care. This necessarily requires a consideration of the standard of care applicable in the circumstances of each appellant.
4. The starting point for this consideration is the provisions of ss 11 and 12 of the Civil Liability Act. Those sections provide as follows:

(1) A person does not breach a duty to take reasonable care unless -

(a) there was a foreseeable risk of harm (that is, a risk of harm of which the person knew or ought reasonably to have known); and

(c) in the circumstances, a reasonable person in the position of the person would have taken precautions to avoid the risk.

(2) In deciding whether a reasonable person would have taken precautions against a risk of harm, the court is to consider the following (among other relevant things):

(a) the probability that the harm would occur if care were not taken;

(c) the burden of taking precautions to avoid the risk of harm;

(d) the potential net benefit of the activity that exposes others to the risk of harm.

(3) For the purpose of subsection (2)(c), the court is to consider the burden of taking precautions to avoid similar risks of harm for which the person may be responsible.

In a proceeding relating to liability for breach of duty -

(a) the fact that a risk of harm could have been avoided by doing something in a different way does not of itself give rise to or affect liability for the way in which the thing was done; and

(b) the subsequent taking of action that (had the action been taken earlier) would have avoided a risk of harm does not of itself give rise to or affect liability in relation to the risk and does not of itself constitute evidence of liability in connection with the risk."

1. A number of observations are appropriate concerning the applicability of those provisions to the circumstances of this case. Firstly, having regard to the evidence before the trial judge, and in the light of the principles expressed in s 11 of the said Act, it was an inevitable conclusion that a reasonable person in the position of each appellant would have taken precautions to avoid the risk associated with the escape of cattle from the paddock. There was a foreseeable risk of harm which was not insignificant. If cattle escaped from the farm, then it was obvious that they might pose a risk to traffic on Back Line Road and on the busy Bass Highway. This was precisely the risk which materialised on the night in question.
2. Secondly, the provisions of s 11(1)(c) reflect the common law position that the assessment of reasonable precautions must be judged in the light of a person in the position of, and with the knowledge and capacities of, the appellants. It is a necessary ingredient of proof of breach of duty that it be established that the defendant acted unreasonably in doing what he did, and in not doing it in some other way (Dovuro Pty Ltd v Wilkins [2003] HCA 51, 215 CLR 317; Shoalhaven City Council v Pender [2013] NSWCA 210; State of New South Wales v Briggs [2016] NSWCA 344). The question of reasonableness will be judged against the standard determined in accordance with the normal skill, intelligence and knowledge of the person in the position of a defendant. The question of the appropriate standard of care, and in particular the question of what a reasonable person in the position of a defendant would have done, must be judged prospectively, and not with the use of hindsight. Vairy v Wyong Shire Council [2005] HCA 62, 223 CLR 422; State of New South Wales v Briggs.
3. The effect of s 12(a) of the Civil Liability Act confirms the common law that proof that the risk of harm could have been avoided by doing something in a different way is not, of itself, sufficient to establish liability arising from the way in which the thing was done. The focus of the assessment must be on whether what the person did or did not do complied with the standard that would be expected of a reasonable person in the position of that person, and the fact that a different precaution could have been taken does not, of itself, establish a breach of duty.
4. It must be said that there was little, if any, consideration by the trial judge of the standard of care which was applicable in the circumstances, and whether each appellant was negligent by reference to that standard. In relation to the Lesters, the relevant finding by her Honour was, "They did not check that the furniture they provided for use was fit for the purpose for which it was to be used." [147]. Her Honour did not particularise in any greater detail what it was that the Lesters ought to have done to check that the gudgeon pin actually used was fit for purpose, nor assess that expectation against the standard applicable to a reasonable farmer in their position. In relation to CHFPL, her Honour concluded that the company was held out "to be experienced fencing contractors". She found that, "As an experienced fencing contractor, Blizzard had to have been aware that any 'furniture' he used for the latching mechanism was fit for the purpose for which it was used, and that any gate and latching mechanism he installed would be secure enough to hold the type of cattle the Lesters had." [177] There was no further consideration of the standard applicable to "an experienced fencing contractor".
5. In this case, the expert opinion expressed by Ms Gaffney and Mr Carroll, based on expert testing and analysis conducted since the escape, provided a strong basis for a conclusion that the use of the gudgeon pin with recessed thread was inadequate to secure the gate against pressure that might foreseeably be applied by cattle. However, a real question arises as to whether a reasonable person in the position of each appellant ought to have appreciated the existence and extent of that inadequacy, and therefore investigated and utilised alternative means to secure the gate, including by making inquiry of appropriate experts. It cannot be assumed that the appellants were required to know the information expressed in the expert evidence (see Wilson v Nilepac Pty Ltd [2011] NSWCA 63). They were required to apply the standards applicable to a reasonable person in their respective positions. If the evidence discloses that a reasonable person would have anticipated that the gudgeon pin with recessed thread was inadequate and made appropriate expert inquiry, then the question arises as to what precautions would have been taken by a reasonable person, and what level of force a gate constructed with the exercise of reasonable care ought to have been able to withstand. Implicit in this question is an acceptance of the proposition that the standard applicable to a reasonable person in the circumstances of the appellants is not one that provides insurance against the occurrence of injury arising from the escape of cattle, but rather one that requires that reasonable care be taken to avoid such injury. Accordingly, in order to determine whether or not there was a breach of duty, her Honour was required to evaluate what was actually done by each appellant, having regard to the response and standard of construction that would have been expected of a reasonable person in their respective positions, given the foreseeable risk that force might be applied by cattle to the gate.
6. On the unchallenged evidence, it seems clear that the Lesters left the selection of the means of securing the gate, and the actual equipment to be used, to Mr Blizzard. They provided him with access to a bucket which contained various used gudgeon pins and chains and other unspecified items. They did not instruct him to use any particular method or item in order to secure the gate. It is open on the evidence to conclude that had Mr Blizzard expressed reservations about the sufficiency or adequacy of the items in the bucket, and requested permission to secure other items, they would have readily agreed and paid for those items. However, the choice of a system of securing the gate seems to have been as simple as Mr Blizzard selecting the gudgeon pin and chain and using that method. When the Lesters used the gate after it had been installed, but before the accident, there is no suggestion that they queried or disagreed with that choice.
7. The expert evidence as to the inadequacy of the gudgeon pin and chain to withstand the force which might be applied in foreseeable circumstances by cattle grazing in the paddock, derives from a state of knowledge acquired by the specialised training and experience possessed by Mr Carroll and Ms Gaffney as engineers, together with testing and analysis conducted by them since the occurrence of the damage. It can be safely inferred that this level of knowledge would be well in excess of that expected to be possessed by a person in the position of either the Lesters or Mr Blizzard. The Lesters were farmers and Mr Blizzard was a fencing contractor. Clearly, it can be inferred that they would have significant familiarity with fences and gates and various methods to secure same, but certainly not to the level of detailed technical knowledge upon which the expert opinions of Mr Carroll and Ms Gaffney were based.
8. There was no evidence in the trial which directly addressed the question as to the level of knowledge which an experienced fencing contractor or farmer ought to have possessed in relation to the pull out force of a gudgeon pin with recessed thread, the breaking point of a chain, or the force which might potentially be delivered by even one cow leaning or rubbing against the gate. There was evidence to suggest that it was common practice for cows to act in this way. Mr Ralston, Mr Armstrong, Professor Phillips and Mr Carroll each gave evidence to this effect. However, apart from the opinion already discussed concerning the effect of such conduct on the part of cattle, based on expert knowledge and testing, the evidence did not address directly the question of what a reasonable person in the position of the appellants would be expected to know about the consequences of such conduct on a securing system such as that used in this case.
9. However, there was some evidence concerning practices relating to the securing of gates, applicable on farms in the relevant area at that time. This evidence is as follows:

(a) Mr Armstrong's evidence was that the chain and ring mechanism properly installed was the "minimum security requirement" regarding this situation. He also said that cattle commonly rub against gates, often bending them as a result. His opinion was that this could be avoided by running an offset wire inside a gate.

(b) Mr Armstrong in his report dealt with standards and recognised practices with respect to methods of securing mechanisms of gates on farms. In particular, the report states:

"18 The gates viewed in my survey along Bass Highway are typical of those in farms throughout Tasmania. Of the 27 gates to Bass Highway between the Stanley Highway and Back Line Road (see Appendix 2):

10 were locked with a chain and padlock on 29 December 2008.

16 were secured with chain and rings (like the gate in question).

11 had an electric offset wire installed across the gate inside the paddock (these were not tested to check whether they were 'alive')."

"4 The chain and ring mechanism used on the gate has been a common method for securing gates on Tasmanian farms. Of 27 gates with access to the Bass Highway, 16 have similar securing mechanisms (chain a [sic] with ring and gudgeon). These gates between the Stanley Highway junction and Back Line Road, were surveyed on 29 December 2008 (details in Appendix 2). Note that a number of gates also had additional security, such as a second chain and padlock, and / or an offset electric wire."

(c) Professor Phillips agreed that it was normal practice for cattle to rub against a solid object such as a gate or a fence post. However, he expressed the opinion that use of an offset electric wire to deter cattle from doing so was not common practice for operational reasons.

(d) Mr Ralston gave unchallenged evidence that he is a farmer experienced with beef and dairy cattle. He said that he had been a farmer all his life and was born on a farm. He was at the time of the trial operating a property which contained a herd of cattle consisting of 100 to 180 head. He maintained both boundary and internal fences, and normally employed a contractor for the purpose of boundary fencing. He had been looking after his own fencing since 1980. Mr Ralston's evidence was that he used electrified offset wires on internal gates but not on boundary gates. He had seen cattle rubbing against gates and causing damage. He estimated that he had seen damage caused on approximately half a dozen occasions over the last few years. He described the damage as "if they're securely fastened I think they will bend the gates or alternatively, they'll bust chains and gudgeons will pull out -". His evidence as to his practice with respect to the securing of gates on his boundary fences is as follows:

"How are your boundary fences latched?......Mine have a different gudgeon and I have a chain, a three eight galvanised chain and lock - a padlock on it.

That goes around the strainer post and the gate?......The strainer post and around the gate, yes.

(e) Mr Carroll was not asked to and did not comment on contemporary standards of gate construction, nor as to what knowledge a farmer or an experienced fencing contractor ought to have had at the time in question. However, in his supplementary report, he did express the following opinion.

"Securing a farm gate is achievable by some robust methods and alternatively by barring or dissuading cattle from approaching a gate. Various methods were available on or before 26 June 2008 that could reasonably have been employed to secure the 'escape gate' effectively. These include:

• Installing the 'latch hook' approximately perpendicular to the orientation of Backline Road together with a very sturdy Hi-Tensile chain.
• Using a sturdy Hi-Tensile steel chain looped several times through the gate end stile and around the latch side post which is anchored by a very strong padlock or shackle.
• Installing an electric fence across the width of the gate opening to prevent the cattle from contacting the gate. This is the method that is utilised on the farm at the 'escape gate' now as I've observed during my visits to Backline Road; it has an electrified offset wire mounted along the paddock side of the gate linked to the adjacent 'electric fence' along the property boundary."

1. Mr Carroll was not asked any questions in evidence-in-chief or in cross-examination in relation to this opinion.
2. Of course, the fact that according to Mr Carroll there were alternative "robust methods" available at the relevant time that, in his opinion, "could reasonably have been employed to secure the 'escape gate' effectively", does not deal with the question of what a reasonable person in the position of the appellants should have known or would have done at the time in question: Civil Liability Act, s 12(a). Further, in the absence of a finding as to the force which was actually applied on the night in question, and an assessment of the ability of these methods to deal with that force, it is not open to conclude that they were methods which, if employed, would have avoided the escape of the cattle on the night in question.
3. In Dovuro Pty Ltd v Wilkins (above) McHugh J said:

"If negligence law is to serve any useful social purpose, it must ordinarily reflect the foresight, reactions and conduct of ordinary members of the community or, in cases of expertise, of the experts in that particular community. To hold defendants to standards of conduct that do not reflect the common experience of the relevant community can only bring the law of negligence, and with it the administration of justice, into disrepute. That is not to say that a defendant will always escape liability by proving that his or her conduct was in accord with common practice. From time to time cases will arise where, despite the common practice in a field of endeavour, a reasonable person in the defendant's position would have foreseen and taken steps to eliminate or reduce the risk that caused harm to the plaintiff. But before holding a defendant negligent even though that person has complied with common practice, the tribunal of fact had better first make certain that it has not used hindsight to find negligence. Compliance with common practice is powerful, but not decisive, evidence that the defendant did not act negligently. And the evidentiary presumption that arises from complying with common practice should be displaced only where there is a persuasive reason for concluding that the common practice of the field of activity fell short of what reasonable care required."

1. The above stated evidence of Mr Armstrong provides some evidence that use of a gudgeon pin, chain and ring to secure a boundary gate intended to hold cattle was, at the relevant time, a common practice on Tasmanian farms. There was no evidence to the contrary of this opinion. Mr Ralston's evidence went no further than describing his own practice. There was no attempt to relate his practice to the wider industry.
2. It follows that the evidence did not permit a conclusion that a person in the position of either appellant would have realised that the use of a gudgeon pin with recessed thread would be inadequate to prevent the escape of cattle. Further, the evidence does not establish that the appropriate standard of care required either appellant to obtain expert engineering advice as to the adequacy of the gudgeon pin or an alternative means of securing the gate. Apart from Mr Ralston's experiences, there was no evidence that would permit a conclusion that the appellants ought to have been alerted to the inadequacy of the pin or the extent of force which could be incidentally applied by a cow. To the contrary, Mr Armstrong's evidence, based on his experience as an agricultural consultant, would suggest that the accepted industry view was that use of a correctly installed pin and chain was adequate for this purpose. Although with the benefit of hindsight and expert testing, it has been established that the gudgeon pin of the type used was inadequate, there is no evidence that would establish that this was something which was appreciated or ought to have been appreciated by a person in the position of each appellant at the relevant time.
3. In summary, therefore, it was open to her Honour to find that the gudgeon pin with recessed thread, particularly when used in the way it was in this case, was not "fit for purpose", or to express this in a way more appropriate to the issue which arose, not adequate to obviate the risk of cattle escaping from the paddock. However, this conclusion did not necessarily lead to a conclusion that, by using that pin, the appellants had fallen below the standard expected of a person in their respective positions. We are satisfied that her Honour did not adequately consider that question, and further, that had she done so, it was not open to her Honour on the evidence presented to her, to be satisfied that the use of the pin fell below that standard.
4. Accordingly, it follows that her Honour erred in finding that each appellant was in breach of his duty of care to Mr House.

1. In order to establish liability on the part of an appellant, it was necessary for the MAIB to prove that an established breach of duty by that appellant had caused the injury and loss suffered by Mr House. A necessary link in the chain of causation was proof that the breach of duty on the part of any appellant had caused the escape of cattle on the night in question.
2. Having regard to the conclusion expressed above that the evidence did not establish a breach of duty on the part of any appellant, the question of causation does not arise. However, even if her Honour had correctly concluded that the use of the gudgeon pin and chain system to secure the gate did amount to a breach of duty on the part of any of the appellants, the question would still arise as to whether that breach was causative of Mr House's injuries.
3. It is now well established that the effect of s 13(1)(a) of the Civil Liability Act is that in order to establish factual causation, the appropriate test is the "but for" test. (See Adeels Palace Pty Ltd v Moubarak [2009] HCA 48, 239 CLR 420; Strong v Woolworths Ltd [2012] HCA 5, 246 CLR 182.) In the circumstances of this case, it was therefore necessary for the MAIB to prove against each appellant that, but for the failure of that appellant to take steps to secure the gate against the escape of cattle in a manner consistent with that of a reasonable person in the position of the appellant in question, the cattle would not have escaped on the night in question. Given that her Honour found that the relevant breach on the part of each appellant related to the use of a gudgeon pin with recessed thread, the finding which was necessary was that, had that pin not been used, but some other means used to secure the gate, the cattle would not have escaped.
4. Both appellants make the following point in relation to this issue. The trial judge, at [145], expressly refrained from determining how it was that the gudgeon pin became detached from the gatepost. Her Honour stated that she did not "need to determine precisely what the level of force was which was applied to the gate, fencing or posts". The appellants submit that without determining the level of force which was applied, it is impossible to conclude that a decision not to use a gudgeon pin with recessed thread, but to use some other method of securing the gate, would have successfully resisted the force which was actually applied. In other words, without determining what force was applied to cause the gate to open, it is impossible to conclude that use of some other method would have made any difference, and that the cattle would not have escaped in any event.
5. The MAIB deals with this aspect by pointing to other alternatives which, it submits, having regard to the evidence, would, on the balance of probabilities, have adequately resisted the force applied by cattle on the night in question. Examples are use of electrical offset wire or chain and padlock. The MAIB relies on Mr Ralston's evidence about his use of chain and padlock on boundary gates, and Mr Carroll's evidence concerning this being a robust method available for securing a farm gate.
6. The trial judge's reasoning in respect of causation seems to be contained within her impugned comments in [145] and [146]. In effect, her Honour's reasoning in respect of this question was as follows:

(a) The gudgeon pin was loose in the post to the point where even minimal force could cause it to fall out.

(b) Therefore, with the application of some force, irrespective of what it was or the extent of it, the gudgeon pin did fall out.

(c) Therefore, the gate was opened, the cattle escaped and the injuries were caused.

1. With respect, this reasoning is fallacious. Firstly, it relies on a finding that the gudgeon pin was loose in the post immediately before force was applied, which finding was not open for the reasons already stated. Secondly, the reasoning does not address the critical question of whether, but for the failure to secure the gate in a manner consistent with what a reasonable person in the position of the appellants would have done, the cattle would still have escaped. In order to determine this question, it was necessary to make findings as to the following:

(a) What degree of force ought the fence, constructed and secured in accordance with the application of reasonable care, have been able to withstand?

(b) Was the force actually applied on the night in question greater or less than that level of force?

1. Her Honour did not make any finding as to what actually occurred, apart from the fact that some level of force was applied, the post moved away from the vertical, and the gudgeon pin fell out. It would have been open to the trial judge, in our view, on the evidence, to find that the most probable cause of the application of force was that exerted by one or more animals. Whilst there was some evidence which suggested that the original strainer post had been inserted into wet, soft ground, so that Mr Blizzard felt the need to provide some support for it, the evidence of the Lesters would suggest that the gudgeon pin and post were both still firmly in place shortly before the night of the escape. The only medium in the paddock in close proximity to the gate and able to apply significant force on the night in question were the cattle grazing in the paddock. In our view, there is a strong inference available that the gate came open because of the force applied by cattle.
2. However, the evidence did not permit a finding to be made as to the level of that force. There was no direct evidence as to what had occurred to cause the gate to come open. The circumstantial evidence on this question was limited to the condition in which the opened gate, and post, were found the next day. The expert evidence established that one cow rubbing or leaning against the gate could impart a force of between 450 and 600 kg. It would seem to be an inescapable conclusion that if more than one animal was involved in rubbing or leaning against the gate or the post contemporaneously, then the force would be significantly greater than 600 kg. The expert evidence established that if the gudgeon pin was able to withstand such pressure, the chain would snap at 199 kg, but also, that the gudgeon pin, even if properly inserted, would become detached from the post at a pressure considerably less than 199 kg. The pressure which was therefore applied could have been as little as that calculated by Ms Gaffney as the pull out resistance of the gudgeon pin, something less than 95 kg, or as great as several cows leaning and rubbing against the gate at the same time, which would impart very substantial pressure indeed. In either case, with this gudgeon pin, the result would have been the same. The pin would have been pulled from the post and left in the condition in which it was found by Mr Ralston on the following morning, and this would have happened before the chain snapped, irrespective of the degree of potential force which was actually applied. The gate would thereby have come open and the cattle would have escaped.
3. In this regard, it is accepted that it is not necessary for a plaintiff to establish the mechanism of the cause of loss with precision. The factual causation of loss by the breach of duty of a defendant is to be assessed on the balance of probabilities, including in circumstances in which alternative causes are possible: Strong v Woolworths Ltd (above); Langmaid v Dobsons Vegetable Machinery Pty Ltd [2014] TASFC 6, 24 Tas R 18. However, in this case, the evidence simply did not permit a finding, even on the balance of probabilities, that the force applied was at any particular level, provided it was greater than the force required to overcome the pull out resistance of the pin, something less than 95 kg.
4. Given that the force which may have been applied on the night in question could not be established, and could have been as great as that exerted by more than one cow, the question which arises is whether the use of an established method of securing the gate other than the pin and chain would, more probably than not, have prevented the escape of the cattle. The other alternatives were the chain bound around the post and gate and secured with a padlock, or an electric offset wire. With respect to these alternatives, the trial judge findings were as follows:

(a) Her Honour was not satisfied that the failure to use the chain and padlock method amounted to a breach of duty on the part of any of the appellants. In discussing the question in the context of the Lesters, her Honour noted that "the use of padlocks, while perhaps an ideal, was something more directed to protection against trespassers than a routine method of preventing the escape of stock".

(b) On the question of whether the Lesters were negligent for not using electrical offset wire, her Honour said as follows:

"[153] The evidence suggests the steers which escaped this night had only been in the particular paddock for maybe two days. Further, the evidence was that not all fences were electrified. Electrifying the escape gate may have deterred the steers from going near it. Clearly, however electrification does not always deter cattle. The evidence of Mr Ralston about what the cattle did this night when he was attempting to get them back into the paddock and of Mr Korpershoek about cattle going through electric fences, indicates that they do not in all circumstances act as a deterrent.

[154] I am not satisfied that the MAIB has established to the requisite degree that electrifying the escape gate would necessarily have deterred the cattle from exiting the paddock through it, or that failure to electrify that particular gate represented such a departure from what a reasonable farmer would have done such as to amount to a breach of a duty to road users."

(c) On the question of whether CHFPL was liable for not using an electric offset wire, her Honour simply said:

"[172] This particular cannot be made out as against the third defendant because it was never part of its instructions to provide for electrification of the gate. If anyone was to do that, it was to be the Lesters."

(d) However, in an apparent inconsistency, her Honour found in respect of the contribution proceedings, that the Lesters' contribution to liability of 65% was to be assessed on the basis that they "provided materials and that they did not fit an electrical stand-off wire".

1. The evidence which related to the utility of these methods as a means of securing the gate can be summarised as follows:

(a) The results of Mr Armstrong's survey of 27 gates with access to the Bass Highway in that area, established that of the 27 gates surveyed, 14 used chains and padlocks as a securing mechanism, and 11 had an electric offset wire installed across the gate inside the paddock.

(b) Mr Ralston's evidence discussed above concerning his practice on his property, which included utilisation of both methods.

(c) The opinion expressed by Mr Carroll, that included these methods among the "robust methods" that in his opinion "could reasonably have been employed to secure the escape gate effectively".

1. However, there was little, if any, evidence that dealt with the capacity of these methods to resist force applied by cattle. In the absence of a finding as to the force which was actually applied to the gate on the night in question, and the force which a gate constructed in accordance with these methods would be able to withstand, it was impossible to determine that the cattle would not have escaped in any event. Her Honour was, with respect, correct to reject the failure to utilise these other alternatives as a basis for liability on the part of any appellant. However, she did not make a finding relating to the force which such methods could withstand, nor was such a finding available from the evidence. There was an inference available equally consistent, on the balance of probabilities, with any other scenario, and not able to be excluded on the evidence, that a force was applied by cattle on the night in question which would have caused the gate to come open, irrespective of the method chosen by the appellants to secure the gate. It follows that on the available evidence, and on the assumption that the use of the gudgeon pin and chain to secure the gate was negligent, the MAIB had not established factual causation, and her Honour erred in finding that it had done so.

1. Having found both appellants liable, her Honour apportioned liability on the basis that the Lesters should bear 65% and CHFPL 35%. This apportionment has been the subject of appeal by the Lesters.
2. In the light of our conclusion with respect to liability, it is not necessary, nor indeed possible, to determine this aspect of the matter. Liability has not been established against either appellant, and accordingly the issue of apportionment in contribution proceedings does not arise.

1. For these reasons, we have decided to allow the appeal of each appellant, set aside the orders of the trial judge, and in lieu thereof enter judgment for each appellant.