GIBBS C.J.: This is an appeal from a judgment of the Supreme Court of Victoria (Crockett J.) declaring that the respondent sustained an injury as defined in a policy of insurance by which the appellant company agreed "subject to all the provisions, definitions, limitations and conditions of this Policy ... to pay indemnity for disability covered by this Policy and sustained by the Insured resulting from injury and sickness; in the manner and to the extent herein provided". The policy defined "injury" to mean "bodily injury of the Insured caused by an accident occurring while this Policy is in force and resulting directly and independently of all other causes in loss covered by this Policy". The policy contained a provision for the payment of monthly indemnity which so far as is material was as follows:

Monthly Indemnity stated in the Policy Schedule not

heading "Accident" was "lifetime" and under the heading "Sickness" was "2 years". The respondent, a tiler, when levelling a mixture of sand and cement, sustained a back lesion - a central disc prolapse - which resulted in his total disability. To level the mixture he used a scrimmer, an implement which has a long straight edge made of aluminium, which he had to draw towards him, thus banking up the sand and cement. The task was a heavy one and required the respondent to squat or bend. He had been doing work in this way for a period of about fifteen years. He was aged 33 and fit. Crockett J. was asked to find that the respondent must have had a prior degenerative condition; instead he found that whether the respondent had an earlier degenerative condition in his spine or not, it played no part in the production of his bodily injury. The learned judge further found that the work that the respondent was doing was a significant traumatic event, and that it created pressure on the respondent's spine and caused the prolapse. The appellant paid the monthly indemnity for two years on the basis that the respondent's disability was by reason of sickness, but disputed liability to make further payments. The sole question for our decision is whether the respondent's disability was "bodily injury ... caused by an accident" within the meaning of the policy.

2. It was conceded that the bodily injury sustained by the respondent was accidental, but it was said on behalf of the appellant that it was not "caused by an accident". The submission was that there is an injury within the meaning of the policy only when the bodily injury has resulted from a separate occurrence which can itself be described as an accident. In the present case, it was said, the bodily injury resulted from the exertion involved in the use of the scrimmer, but the cause of the injury was not an accident, because the respondent intended to use the scrimmer in the way that he did.

3. We were referred to a number of cases in which the courts have considered the meaning of policies of accident insurance containing the same words as those of the policy in the present case, or similar words. None of those decisions is binding on this Court, but if the precise words used in the policy in question have acquired a settled meaning, this Court should in my opinion be slow to introduce confusion into the insurance industry by departing from that meaning. However, as will be seen, the meaning of the critical words in the policy is far from settled.

4. It is convenient first to refer to decisions on the very words of the present policy: "bodily injury ... caused by an accident". In Canada the meaning for which the appellant contends has been accepted as correct. In Columbia Cellulose Co. v. Continental Casualty Co. (1963) 40 DLR (2d) 297, a decision of the British Columbia Court of Appeal, Sheppard J.A. said, at p 301:

"Under the policy there must be an accident which

caused the bodily injury and therefore the accident

must be distinct and separate from that bodily

injury so as to be the cause thereof. On the

literal meaning of the policy the accident must be

the cause of the injury: it is not sufficient that

the injury, that is the consequence, be an

accident."

The Supreme Court of Canada dismissed an appeal from that decision and approved the judgment of the Court of Appeal (42 D.L.R. (2d) 401) and has since again approved and followed the judgment of Sheppard J.A.: Smith v. British Pacific Life Insurance Co. (1965) 51 DLR (2d) 1. In Lipertis v. Australian Casualty Company Pty. Ltd. (1983) 2 VR 280 Kaye J. took a similar view and held that the insured, to establish his claim under a policy in that form, was required to prove that the injury which he suffered was caused by some involuntary act or by an external happening which interfered with his voluntary actions: see at p.283. On the other hand, Starke J. in A.F. & G. Robinson v. Evans Bros. Pty. Ltd. [1969] VicRp 110; (1969) VR 885 held that the words "accidental damage arising out of an accident" are a composite term which is concerned with the quality of the damage rather than its cause.

5. A longer line of authority has interpreted policies which provide indemnity against "any bodily injury caused by violent, accidental, external and visible means". Reference to violent, external and visible means may make that formula more stringent than that used in the policy in the present case, but the requirement that the bodily injury be caused by accidental means is not dissimilar to that of the present policy. A number of cases have held that these words make it necessary to distinguish between the bodily injury and the means by which it was caused, and that the means will not necessarily be accidental even though the injury itself can properly be described as accidental: Clidero v. Scottish Accident Insurance Co. Limited. (1892) 19 Sess. Cas. 355; Long v. Colonial Mutual Life Assurance Society Ltd. (1931) NZLR 528; Steinke v. Australian Provincial Assurance Association Ltd. (1944) St.R.Qd. 7; Dennis v. City Mutual Life Assurance Society Ltd. [1979] VicRp 9; (1979) VR 75; National & General Insurance Co. Ltd. v. Chick (1984) 2 NSWLR 86, see at pp 91-92, 100-102; cf. at pp 111-112. Other authorities have adopted a different approach. In the much discussed case of Hamlyn v. Crown Accidental Insurance Company (1893) 1 QB 750, the plaintiff, in stooping to pick up a marble dropped by a child, dislocated the cartilage of his knee. The English Court of Appeal held that the injury was caused by violent, accidental, external and visible means. The judgments, in so far as they dealt with the question whether the injury was caused by accidental means, were short and a little delphic. Lord Esher M.R. said, at p.753:

"To do that (pick up the marble) he separated his

knees and stooped forward, bending his knees. He

seems to have done this awkwardly; at all events,

in doing it he wrenched his knee, and that did the

mischief, and that wrench was the cause of the

injury. That that was accidental I cannot doubt.

He did not mean to wrench his knee, and that would

not be the ordinary result of such an action."

Some later authorities have attached some significance to the fact that what the plaintiff did was done awkwardly, but I cannot believe that this circumstance formed any part of the ratio of the decision. Lopes L.J. said, at p.754:

"The cause of the injury was accidental in the

sense that the injury was a casualty and unforeseen

and unexpected."

"They (the means) were also accidental, for getting

into the particular position in which the injury

could happen was not done on purpose."

The case was explained by Bray J. in In re Scarr and General Accident Assurance Corporation (1905) 1 KB 387, at p 394 on the basis suggested by A.L. Smith L.J., namely that the plaintiff did not mean to get into a position in which he might wrench his knee, and in Long v. Colonial Mutual Life Assurance Society Ltd. (in the New Zealand Court of Appeal), at p 541, it was similarly suggested that the judgment was based on the finding that there was an involuntary and unintended movement causing the injury. Hamlyn v. Crown Accidental Insurance Company was a case in which the insured, while doing what he intended to do, in some unexplained manner involuntarily moved in a way which caused his injury. The learned authors of McGillivray & Parkington on Insurance Law, 7th ed. (1981), at p.749 (par.1792), and those of Halsbury, 4th ed., vol.25, par.603 regard the case as providing support for the view that the words "accidental means" add nothing to the word "accident". Similarly the majority of the Full Court of Victoria in Federation Insurance Ltd. v. R Banks [1984] VicRp 42; (1984) VR 525 rejected the view that a distinction should necessarily be drawn between accidental results and accidental means, and held that a bodily injury caused accidentally is a bodily injury "caused by accidental means": see per Starke J., at pp.528-531 and Brooking J. at pp.542-543; contra Kaye J. at pp 537-538. In that case as in A.F. & G. Robinson v. Evans Bros. Pty. Ltd., Dennis v. City Mutual Life Assurance Society Ltd. and National & General Insurance Co. Ltd. v. Chick reference is made to the United States authorities which reveal a similar conflict of opinion.

6. The ordinary rules of interpretation apply to a policy of insurance. As in the case of any other commercial contract, a court may depart from the strictly literal meaning of a particular expression to place upon it an alternative construction which is more reasonable and more in accord with the probable intention of the parties if the words will bear that construction: McCowan v. Baine (1891) AC 401, at p 403; see also McGillivray & Parkington, op.cit., at pp 436, 437 (pars.1037, 1039) and Sutton, Insurance Law in Australia and New Zealand (1980), p.294, par.8.45. Further "the trend is, if anything, to adopt a liberal interpretation in favour of the assured, so far as the ordinary and natural meaning of the words used by the insurers permits this to be done": Halsbury, 4th ed., vol.25, par.594, note 1, cited in Mount Albert City Council v. New Zealand Municipalities Co-operative Insurance Co. Ltd. (1983) NZLR 190, at p 193. Notwithstanding this potential liberality of construction, with all respect I find it impossible to agree that the words "bodily injury ... caused by an accident" in the policy simply mean "accidental injury". The words "an accident" can by themselves be applied either to an event which happens fortuitously or to the consequences of such an event, but in the context of the policy in the present case they describe the cause of the bodily injury; the cause must be an accident, and it is not enough that the resulting bodily injury may be described as accidental. However, the words "caused by an accident" naturally refer to the proximate or direct cause of the injury, and not to a cause of the cause, or to the mere occasion of the injury. Thus, to take the example given in In re Scarr and General Accident Assurance Corporation, at p 394, if a man while walking stumbles and sprains his ankle, the injury is caused by an accident - the stumbling - and not by the deliberate act of walking. Or a person goes swimming, becomes exhausted and drowns - surely the death is caused by an accident: cf. Long v. Colonial Mutual Life Assurance Society Ltd., at p 530. Further, the words of the policy do not require that the cause should be one which it is possible to identify. If it can be inferred that some accident - some unintended and unforeseen (and perhaps unforeseeable) happening - must have occurred to cause the injury, the insured will be entitled to recover under the policy. That conclusion is completely in accord with Hamlyn v. Crown Accidental Insurance Co., where, as has been said, it was not made clear what unexpected movement caused the plaintiff's knee to be wrenched while he was voluntarily performing the series of acts necessary to enable him to pick up the marble. In Federation Insurance Ltd. v. R. Banks, at p 538, Kaye J. cited from the judgment in Long v. Colonial Mutual Life Assurance Society Limited, at p 541, where Kennedy J. said:

"If a person suffering from a weakness or disease

should voluntarily subject himself to conditions

which would not injuriously affect persons in

ordinary health, but would be dangerous to him, a

resulting injury could not be said to have been due

to accidental means. But if a voluntary act, which

causes injury, is one usually performed without

injury and is not calculated, in the ordinary

course of things, having regard to the conditions

obtaining, to produce the consequences which

follow, some fortuitous occurrence, which really

caused the unusual result, may be inferred."

In Federation Insurance Ltd. v. R. Banks the insured, while playing cricket, "took off for a quick single" and as he did so suffered a rupture of the Achilles tendon of the right leg. There was no evidence suggesting that the degree of pressure which he applied was any different from that which he had applied on previous occasions when playing cricket without suffering any injury and there was no evidence that he was suffering from any pre-existing disability. Although Kaye J. interpreted the policy differently from the other members of the court, he agreed with them that the insured was entitled to recover, since in his opinion it was open to the trial judge to conclude "that on this occasion something additional and unknown occurred in or in association with the respondent's ankle, and it was that activity which caused the injury": see at p.540. I respectfully agree with this approach to the effect of the policy. It is an approach which may cause difficulties in a case where before the accident the insured was suffering from some physical condition, known or unknown, which deteriorated as the result of the accident. However it causes no difficulty in the present case where the learned trial judge refused to find that the insured was suffering from any pre-existing disability.

7. In the present case the respondent had performed the same task, levelling cement and sand, in the same way, by the use of the scrimmer, for many years without suffering any injury. He was young and fit and if he had any existing degenerative condition it played no part in causing his injury. The proper inference is that something caused him involuntarily to exert unusual force which unexpectedly placed additional pressure on his back and caused the prolapse. In those circumstances, the injury was caused by an accident within the meaning of the policy.

WILSON, DEANE AND DAWSON JJ: This appeal is brought by an insurance company from a judgment of the Supreme Court of Victoria (Crockett J.) in favour of the insured under one of its insurance policies. The primary benefit under the relevant policy ("the policy") was the payment of a "monthly indemnity" in the event of the "total disability" of the insured "as the result of injury ... or ... sickness". The judgment in the insured's favour in the Supreme Court was for unpaid amounts of "monthly indemnity" and interest thereon.

2. The insured under the policy was the present respondent, Mr. Domenico Federico. He was born in Italy on 26 October 1945. He went to school in Italy until he was about eleven. Thereafter, he worked on his parents' farm doing general farm work. For practical purposes, he is illiterate in the English language. He came to Australia at the age of eighteen and, about seven months after his arrival, obtained a job with an "Italian tiler" who taught him to be a ceramic tiler. Some ten years later when his employer retired, Mr. Federico "took over the business". He was subsequently joined in it by a brother who was also a tiler and by another brother whose experience was as a concrete worker. The three brothers thereafter carried on the business in partnership.

3. In 1976, Mr. Federico entered into the policy with the appellant company, Australian Casualty Co. Ltd. ("Australian Casualty"). The policy was in force in April 1978 when he suffered a cauda equina lesion caused by a central disc prolapse while he was working as a tiler in the construction of a home at Keilor in Victoria. It is now conceded that, for the purposes of the policy, he became and remains totally unable to "perform" any "gainful occupation". The following summary of the circumstances in which Mr. Federico became disabled is substantially taken from the judgment of Crockett J. in the Supreme Court.

4. It was Mr. Federico's task, as a tiler, to prepare the bed on which the tiles were to be laid to form the kitchen floor. That bed consisted of a dampened mixture of sand and cement. After the mixture had been dumped in the area where it was to be spread, the plaintiff commenced the task of levelling it. To do that, he used a "straight edge" or "scrimmer". This was a tool consisting of an eleven feet long piece of aluminium with a straight, underside edge which could be applied to the surface of the material to spread it evenly. In the levelling procedure followed by Mr. Federico, the tool was drawn towards the operator and, at stages of the process, the material being levelled became banked up against it. Particularly at those stages, the task of drawing the straight edge towards the operator required the exertion of considerable force while the operator was in a squatting or bending position.

5. On the occasion in question, Mr. Federico, who had never previously had any illness and was a fit and strong man, felt pain in his back when levelling the mixture. While not diagnosed or treated until some time later, he had sustained a massive central disc prolapse and consequential damage to the nerves within the spinal canal. Subsequent surgery merely achieved partial alleviation of pain and the prevention of further deterioration in the plaintiff's condition. In the result, Mr. Federico has lost sensation in the buttock and genital areas and suffers pain in his lower back and disability in his right leg and foot. More importantly, he has lost effective control of his ordinary bladder and bowel functions.

6. It is now common ground that, in the present case, the cause of the central disc prolapse is not to be found in any prior injury or pre-existing degenerative condition. While Mr. Federico had suffered the degenerative changes to the spinal area which are to be expected of a 33 year old manual worker, the cause of the prolapse was what the treating surgeon described as "a significant traumatic event", adding the explanation that Mr. Federico's action in moving the sand and cement mixture while his spine was bent involved "tremendous pressure ... through the lumbar disc system". As Crockett J. found:

"Whether (Mr. Federico) had an earlier

degenerative condition in his spine or not, it

played no part in the production of his bodily

injury. Any such previously existing condition was

not of great significance, and could be described

as a very minor condition. The work that he was

doing at the relevant time was a significant

traumatic event and was sufficient to be, and was

indeed, the cause of the prolapse which occurred.

Whilst the prolapse might not have been capable of

being caused by a trivial event, the work (he) was

doing at the relevant time created pressure upon

(his) spine which was anything but trivial in the

relevant sense."

7. As has been said, the primary benefit for which the policy provided was the payment of a "monthly indemnity" in respect of "total disability" resulting from "injury ... or ... sickness". The period during which the indemnity was payable varied according to whether the "total disability" resulted from "injury" or from "sickness". If it resulted from "injury", the liability to pay the indemnity continued for so long as total disability continued. If total disability resulted from "sickness", the liability to pay the indemnity ended after a maximum period of two years. Australian Casualty paid the monthly indemnity under the policy to Mr. Federico for the two years after his disablement. It then refused to pay further amounts. Mr. Federico's disablement was not, it claimed, the result of any "injury" within the meaning of the policy.

8. In the Supreme Court, Australian Casualty sought to support its denial of liability on three distinct grounds. First, it maintained that the prolapse had been caused by some pre-existing degenerative condition. Secondly, it denied that the prolapse and its consequences had resulted in the requisite inability to engage in a gainful occupation. Thirdly, it claimed that, even if caused by the strain of Mr. Federico's exertion in using the straight edge, the prolapse and its consequences were not an "injury" for the purposes of the policy. All three grounds for denying liability were rejected by Crockett J. Not surprisingly, in view of the evidence, Australian Casualty does not challenge his Honour's findings that the prolapse was not caused by a pre-existing degenerative condition and that Mr. Federico was totally unable to engage in gainful occupation. It has confined its appeal to this Court to the ground that, even if caused by Mr. Federico's actions in using the straight edge, the prolapse and its consequences were not an "injury" for the purposes of the policy. At first instance, Crockett J. considered that he was constrained to reject that ground by the decision of the Full Court of the Supreme Court of Victoria in Federation Insurance Ltd. v. R. Banks [1984] VicRp 42; (1984) VR 525. There is some inconsistency between Federation Insurance, Steinke v. Australian Provincial Assurance Association Ltd. (1944) St. R.Qd. 7 (Full Court of the Supreme Court of Queensland) and National & General Insurance Co. Ltd. v. Chick (1984) 2 NSWLR 86 (New South Wales Court of Appeal). This inconsistency provided the basis upon which special leave to appeal direct to this Court was sought and obtained (although only the (unreported) first instance judgment of Miles J. in Chick was cited on the hearing of the application for special leave).

9. The policy is a standard document used by Australian Casualty in the course of its insurance business. It is apparently offered in different States of the Commonwealth to ordinary working people, such as Mr. Federico, who are unlikely to have the advantage of the advice of a commercial lawyer when they purchase from an insurance company protection against the contingency of sustaining disability from earning as a result of injury or sickness. It contains nothing which would be likely to suggest to those to whom it is proffered that its terms are to be construed in any special technical sense or as conveying other than what they convey as a matter of ordinary language read in the context of the whole policy. That being so, the starting point of a consideration of whether Mr. Federico's central disc prolapse and its consequences were an "injury" for the purposes of the policy must be a consideration of what the words of the policy convey, as a matter of contemporary language read in the context of the whole policy, to a reasonable non-expert in this country. If that meaning is plain, it can be of but limited significance if, at other times and in other places, other courts, however eminent, have held that similar words in other policies were to be construed as having had some different meaning.

10. The policy contains special provisions dealing with the "MINIMUM INDEMNITY FOR SPECIFIC ACCIDENTS" (Part V) and an "ADDITIONAL ACCIDENT BENEFIT RIDER" providing for payment of a varying percentage of the "Capital Sum" in the event of "Accidental Death" or "Dismemberment". These special provisions and "rider" are not here in point and, except to the extent that they may assist in the construction of the main body of the policy, may be put to one side. For present purposes, the critical provisions of the policy are to be found in the introductory section, in the definitions of "Injury", "Sickness" and "Total Disability", in the first sentence of Part III dealing with the liability to pay "Monthly Indemnity" and in that part of the Schedule specifying the "maximum benefit period". In those provisions, Australian Casualty is referred to as "the Company" and Mr. Federico is referred to as "the Insured". They read as follows:

"(Australian Casualty) HEREBY INSURES (Mr.

Federico) ... and subject to all the provisions,

definitions, limitations and conditions of this

Policy promises to pay indemnity for disability

covered by this Policy and sustained by the Insured

resulting from injury or sickness; in the manner

and to the extent herein provided.

'Injury' means bodily injury of the Insured caused

by an accident occuring (sic) while this Policy is

in force and resulting directly and independently

of all other causes in loss covered by this Policy.

'Sickness' means sickness or disease of the Insured

contracted and commencing after this Policy has

been in force for not less than thirty days after

its Effective Date and resulting in loss covered by

this Policy.

'Total Disability' wherever used in this Policy

means the inability of the Insured by reason of

injury or sickness to perform each and every

gainful occupation for which he is reasonably

suited by education, training or experience ...

When, as the result of injury and commencing within

thirty days of the accident or as a result of

sickness and commencing while the Policy is in

force, the Insured sustains total disability the

Company will pay periodically the applicable

Monthly Indemnity stated in the Policy Schedule not

to exceed the applicable Maximum Benefit Period

stated in the Policy Schedule as the result of any

one accident or any one sickness. ...

MONTHLY MONTHLY

BENEFIT $600 BENEFIT $600

WAITING PERIOD: WAITING PERIOD:

BENEFITS COMMENCE BENEFITS COMMENCE

AFTER 14 DAYS AFTER 14 DAYS

MAXIMUM BENEFIT MAXIMUM BENEFIT

PERIOD LIFETIME PERIOD 2 YEARS"

11. The first thing to be noted about the above provisions is the consistent joining, as alternatives, of "injury" and "sickness". In the introductory section, in the definition of "total disability" and in Part III, "injury" and "sickness" would seem to be treated as alternatives comprehending the bodily disorders which might intervene after the commencement of the policy to preclude continued engagement in any gainful occupation. In that context, one would prima facie expect that "injury" would include any physical damage to the human body sustained as the identifiable result of a traumatic occurrence such as the external application of force or the internal application of pressure generated by personal exertion and that "sickness" would include bodily disorder sustained otherwise than as the identifiable result of a traumatic occurrence, such as sickness or disease contracted as the result of contagion or "the operation of natural causes such as old age, congenital or insidious disease or the natural progression of some constitutional physical or mental defect" (Halsbury's Laws of England, 4th Ed., vol.25, p.311). The definitions of "injury" and "sickness" are both based upon some such prima facie meaning of the two words since each incorporates the actual word being defined as the basis of definition for the purposes of the policy.

12. The definition of "injury" in the policy is merely restrictive in that it defines the term for the general purposes of the policy by restricting it to an "injury" which satisfies a number of distinct requirements. The first two of those requirements, that the injury be "bodily" and that it be an injury of "the Insured", do no more than make express what would, in any event, have been implied from the context of the policy. They are not here in issue. Nor is the last requirement, that the injury result "directly and independently of all other causes in loss covered by (the) Policy". What is here in issue is the requirement that the "injury" be "caused by an accident occuring (sic) while (the) Policy is in force". It is not disputed that, if Mr. Federico's central disc prolapse and its consequences were caused by an accident, the accident occurred while the policy was in force. The question in issue is whether they were caused by an accident at all.

13. As a matter of ordinary language in this country, an "accident" (from the Latin accidens) means very much what the etymologist would expect. It is something which happens without intention or design. When used with reference to something which causes injury, it means an unexpected and unintended mishap. In that context, the ordinary and natural meaning of the word still corresponds with Lord Macnaghten's definition in Fenton v. Thorley & Co., Limited (1903) AC 443, at p 448 which, although propounded in a Workmen's Compensation Act case, has commonly been accepted as applicable to the use of the word in public liability and other insurance policies: "an unlooked-for mishap or an untoward event which is not expected or designed" (see, to the same effect, Lord Lindley at p.453).

14. The accident or mishap which causes an injury may occur quite independently of any act of the person injured, e.g., as the result of an explosion of a boiler, the collapse of a building or the failure of the brakes of another's motor vehicle. On the other hand, it may be the result of the injured person's own mistake or miscalculation. In the latter case, it may involve an involuntary act of the injured person such as slipping and falling on a slippery floor or dropping a heavy object on one's foot. Or it may represent an unintended and unexpected characteristic or consequence of an intended act such as the application of unintentionally excessive force or the creation of an unintentionally excessive pressure or strain. A person who holds a fragile but sound object so tightly that he unintentionally breaks it, intends to apply force to the object to retain it in his grasp. He does not, however, intend or expect to apply greater force than an object of that kind in a sound condition can withstand and his application of excessive force is an unintended and unexpected mishap which causes the breakage. The breakage is, as a matter of ordinary language, caused by accident or mishap. Again, a person may create internal pressure within his own body by the exertion involved in lifting, pushing or pulling. In such a case, he intentionally does the acts involved in the lifting, pushing or pulling. If, however, by those acts, he creates internal pressure of a kind or to an extent which unintentionally and unexpectedly causes damage to his body, such as straining a muscle or bursting a blood vessel, the creation of internal pressure of that kind or to that extent is an unintended and unexpected mishap. If the muscle or blood vessel be already in an unsound condition, there may be room for argument about whether the straining of the muscle or the breaking of the blood vessel is properly to be seen as having been caused by the pre-existing condition rather than by the unintentional and unexpected excessiveness of the pressure created by the exertion. If it was in a sound condition, however, it will be plain that the damage to muscle or blood vessel was caused by the unintentional and unexpected excessiveness of the pressure. As a matter of ordinary language, the injury in such a case is caused by accident or mishap.

15. In the present case, Mr. Federico intentionally performed the acts involved in levelling the mixture of damp sand and cement with his straight edge. He did not, however, intend to create internal pressure to an extent which his disc system could not withstand. As has been said, it is now common ground that Mr. Federico's injuries were not the result of any pre-existing degenerative condition. They were the result of the pressure through the disc system being more than his body could withstand without serious injury while he was in a bending or squatting position. That excessive pressure caused the central disc prolapse, forcing disc substance into the spinal canal where the nerves were compressed and damaged. The creation of pressure of a kind which his body could not withstand without serious injury was an unintended and unexpected incident of the acts which he intended to perform. As a matter of ordinary language it was an accident or mishap.

16. Australian Casualty's argument that Mr. Federico's injury was not "caused by an accident" for the purposes of the policy involved reliance upon what was described as "the fundamental distinction drawn by the law between cause and effect". The argument proceeded as follows. An injury is not caused by an accident unless accident and injury can be respectively and distinctly identified as separate cause and effect. If the accident and the injury are one and the same, the former cannot be said to have caused the latter. In such a case, it may be proper to say that the injury was an accidental one. It cannot, however, properly be said that the injury was caused by an accident for the reason that the injury is the accident. Accordingly, so the argument concluded, if an injury is caused, as in the present case, by the doing of an act by the injured person, the injury cannot be said to be caused by an accident unless the doing of the act was itself accidental, whereas the relevant act in the present case was the intended act of levelling the sand and cement mixture.

17. In relation to this argument, the Court was referred to a large number of decisions in this country, the United Kingdom, New Zealand, Canada and the United States of America. The wording of the critical requirement involved in those cases varied considerably. In some cases, it was a requirement, in Workmen's Compensation legislation, that the injury be "by accident" (see, e.g., Fenton v. Thorley & Co., Limited (1903) AC 443; Clover, Clayton & Co., Limited v. Hughes (1910) AC 242). In some, it was the requirement in an insurance policy that the injury or damage be "accidental" (see, e.g., Mount Albert City Council v. New Zealand Municipalities Co-operative Insurance Co. Ltd. (1983) NZLR 190). In others, it was the notoriously obscure requirement (see Lord Cozens-Hardy M.R. in In re United London and Scottish Insurance Company, Limited. Brown's Claim. (1915) 2 Ch 167, at p 170) that the injury be the result of or caused by "violent, accidental, external and visible means" (see, e.g., Clidero v. Scottish Accident Insurance Co., Limited (1892) 19 R. (Ct. of Sess.) 355; Hamlyn v. Crown Accidental Insurance Company, Limited (1893) 1 QB 750; In re Scarr and General Accident Assurance Corporation, Limited (1905) 1 KB 387; Steinke v. Australian Provincial Assurance Association Ltd. (1944) St.R.Qd. 7; Dennis v. City Mutual Life Assurance Society Ltd. [1979] VicRp 9; (1979) VR 75; Cotton v. Phoenix Assurance Company of Australia Ltd. (1982) 2 ANZ Insurance Cases 60-522; National & General Insurance Co. Ltd. v. Chick (1984) 2 NSWLR 86; Federation Insurance Ltd. v. R. Banks [1984] VicRp 42; (1984) VR 525). In others, the requirement was framed in words similar to, or the same as, the requirement of the policy in the present case (see, e.g., Martin v. The Travellers' Insurance Company (1859) 1 F & F 505 (175 ER 828); Columbia Cellulose Co. Ltd. v. Continental Casualty Co. (1963) 40 DLR (2d) 297; affirmed (1964) 42 DLR (2d) 401; Smith v. British Pacific Life Insurance Co. (1965) SCR 434; A.F. & G. Robinson v. Evans Bros. Pty. Ltd. [1969] VicRp 110; (1969) VR 885; Lipertis v. Australian Casualty Co. Pty. Ltd. (1983) 2 VR 280). The judgments in the abovementioned cases and in other cases to which the Court was referred or which are cited in the standard textbooks on insurance law, contain helpful and instructive discussions about the scope of the particular requirement that was relevant for the purposes of the particular case. Some of those cases provide support for Australian Casualty's argument (see, in particular, In re Scarr and General Accident Assurance Corporation, Limited; Columbia Cellulose Co. Ltd. v. Continental Casualty Co; Smith v. British Pacific Life Insurance Co.; the judgments of Kaye J. in Dennis v. City Mutual Life Assurance Society Ltd. and in Federation Insurance Ltd. v. R. Banks). Others militate against that argument and, in our view, support the conclusion reached hereunder (see Martin v. The Travellers' Insurance Company; Hamlyn v. Crown Accidental Insurance Company Limited, at pp 753, 754; Fenton v. Thorley & Co, Limited, at pp 448-450, 452, 453; Clover, Clayton & Co., Limited v. Hughes, at pp 246, 249, 255-256; A.F. & G. Robinson v. Evans Bros.; the judgments of Starke J. and Brooking J. in Federation Insurance Ltd. v. R. Banks; United States Mutual Accident Association v. Barry [1889] USSC 168; (1889) 131 US 100, at pp 121-122 (33 Law Ed 60, at p 67)). It is, however, unnecessary that we embark upon a detailed analysis of the decisions or judgments in those cases. It suffices that we acknowledge the assistance which we have derived from them and turn at once to a consideration of what we see as being, for present purposes, the critical step in Australian Casualty's argument.

18. Even if one accepts the proposition that the requirement of the policy in the present case that the injury be "caused by an accident" is not satisfied unless accident and injury can be identified as distinct cause and effect, it does not necessarily follow that the injury sustained by Mr. Federico would fail to satisfy the requirement. If one is to observe the type of verbal precision upon which the insurer's argument insists, one cannot simply say that Mr. Federico's injury was caused by his action in levelling the mixture of sand and cement. The cause of his injury was the intense and excessive pressure through the disc system which caused the prolapse of the disc and the consequential intrusion of disc material into the spinal column. While Mr. Federico's action in levelling the mixture was intentional, the incidental creation of that internal pressure to an extent greater than his disc system could bear without serious damage was both unintentional and unexpected: it was an accidental incident or consequence of the intended act (cf. Mahoney J.A. in National & General Insurance Co. Ltd. v. Chick, at p 111). Regardless of whether one views the cause of Mr. Federico's injury narrowly as the creation of the internal pressure or more broadly as the acts involved in using the straight edge with the unintended and unexpected incident of excessive internal pressure, it would, in our view, be a distortion of ordinary language to say that Mr. Federico's injury was not caused by an accident. In that regard, the falsity of the argument that the cause of the injury could not be seen as an accident because Mr. Federico intended to perform the acts involved in levelling the mixture of sand and cement lies in the failure to take account of the element of mishap or misadventure involved in the unexpected and unintended circumstance that the internal pressure created as an incident of those acts was greater than his body could bear without serious injury. Indeed, Australian Casualty's argument is answered by the following comments of Lord Robertson in Fenton v. Thorley & Co., Limited (at p 452) with which we agree:

"Much poring over the word 'accident' by

learned counsel has evolved some subtle reasoning

about these sections. I confess that the arguments

seem to me to be entirely over the heads of

Parliament, of employers, and of workmen. No one

out of a Law Court would ever hesitate to say that

this man met with an accident, and, when all is

said, I think this use of the word is perfectly

right. The word 'accident' is not made

inappropriate by the fact that the man hurt

himself. ... Yet the argument ... is ... that

there is nothing accidental in the matter, as the

man did what he intended to do. The fallacy of the

argument lies in leaving out of account the

miscalculation of forces, or inadvertence to them,

which is the element of mischance, mishap, or

misadventure."

19. It follows that Crockett J. was, in our view, correct in concluding that the injuries sustained by Mr. Federico in the present case were "caused by an accident". That being so, those injuries came within the definition of "Injury" in the policy and Mr. Federico was entitled to be paid the "Monthly Indemnity" under the policy for so long as the total disability resulting from them persisted.

20. There are two further matters to which brief reference should be made. The first is that it may, in some cases, be necessary to define with greater precision what is involved in the notion that a mishap be unintended and unexpected. An obvious example of a case where more precise definition of those notions would be required is where the risk of the mishap was foreseen or courted even though it was thought unlikely that it would occur. It is not suggested, however, that the present is such a case. The second matter is that it has not been necessary to consider, for the purposes of the present case, the meaning of the requirement that an injury be caused by (or be the result of) "violent, accidental, external and visible means" or the extent to which an ordinary person purchasing insurance coverage in this country is disadvantaged by such regrettable verbal obscurity in a policy proffered by an insurance company as providing proper and adequate cover against disability through "injury". It should, however, be noted that some of the statements to be found in cases concerned with that requirement to the effect that where an insured is injured in consequence of some action on his own part, he must show either that he made some actual movement which he did not intend or that something unexpected happened external to himself which interfered with his voluntary action, are clearly to be explained by reference to the combined effect of the requirements of "external" and "accidental" and not merely by reference to the requirement that the means be "accidental" (see, e.g., Clidero v. Scottish Accident Insurance Co., Limited, at pp 360 (the Lord President), and 363 (Lord M'Laren) but cf. p 362 (Lord Adam); Steinke v. Australian Provincial Assurance Association Ltd., at p 11). To the extent that such statements cannot be explained by reference to some such combination of requirements but are properly to be seen as relating only to the requirement of "accidental" means or cause, it should be apparent from what has been said above that we respectfully disagree with them.

BRENNAN J.: Wilson, Deane and Dawson JJ. have stated the material facts and the terms of the policy relevant to Mr Federico's claim. Under the policy, Mr Federico is to be paid a monthly benefit of $600 for total disability sustained "as a result of sickness" or "as the result of injury". The term "total disability" is defined to mean the inability of the insured "by reason of injury or sickness" to perform any gainful occupation for which he is reasonably suited. The crucial phrase in the definition of "injury" is "bodily injury ... caused by an accident". "Sickness" is defined to include "disease".

2. Thus a monthly benefit is payable if, by reason of bodily injury caused by an accident or by reason of sickness, Mr Federico is unable to perform any gainful occupation for which he is reasonably suited. The monthly benefit payable when total disability occurs by reason of injury (an "injury benefit") may be payable for life, but the maximum period for which a monthly benefit is payable when total disability occurs by reason of sickness (a "sickness benefit") is two years. As one class of benefits is subject to a time limit and the other is not, a benefit cannot be at once an injury benefit and a sickness benefit: the two classes of benefits are mutually exclusive, though complementary. The distinction between injury and sickness depends on the aetiology of the pathological condition. It is not necessary to define where the boundary between sickness and injury is to be drawn, but only to note that a pathological condition to which some external force has contributed may or may not be an injury. If the pathological condition is occasioned by no more than the buffeting encountered in ordinary living acting on a body that is infirm, a resulting disability should be attributed to the body's infirmity - that is, to sickness - rather than to injury. If there is no antecedent infirmity of body, however, a disability resulting from a pathological condition to which external force has contributed cannot be attributed to sickness; it must be attributed to "injury". If some antecedent infirmity of body and some external force both contribute to a pathological condition, it may be a question of degree whether a resulting disability is to be attributed to sickness or to injury. Mr Federico's total disability must be attributed to injury, for he suffered from no antecedent infirmity.

3. The distinction between sickness and injury is important not only because sickness benefit may be paid for a maximum period of two years but also because injury benefit is not payable unless the injury is "caused by an accident". The insurer's liability to pay an injury benefit is excluded when the insured's bodily injury is not caused by an accident. If the phrase were "injury by accident", the exclusion would not be so wide. Under Workers' Compensation Acts which provide for the payment of compensation for "injury by accident", it is unnecessary to show that an accidental event causes the injury: it is sufficient that the injury is an unlooked for mishap, an unexpected and unintended event; it is enough that the injury itself is unintended and unexpected: see Fenton v. Thorley & Co., Limited (1903) AC 443, at pp 446-447,448,451,452,453; Trim Joint District School Board of Management v. Kelly (1914) AC 667, at pp 675-676, 680-681. In the former case, Lord Lindley said (at p 453):

" The word 'accident' is not a technical legal

term with a clearly defined meaning. Speaking

generally, but with reference to legal

liabilities, an accident means any unintended and

unexpected occurrence which produces hurt or

loss. But it is often used to denote any

unintended and unexpected loss or hurt apart from

its cause; and if the cause is not known the loss

or hurt itself would certainly be called an

accident. The word 'accident' is also often used

to denote both the cause and the effect, no

attempt being made to discriminate between them."

4. There is something to be said for denying the materiality of a distinction between accidental results and accidental causes in an accident policy (cf. per Cardozo J. in Landress v. Phoenix Ins. Co. [1934] USSC 52; (1934) 291 US 491, at p 499 (78 Law Ed 934, at p 938). It is a distinction that the average purchaser of sickness and accident insurance cover is unlikely to appreciate without instruction. Nevertheless there is a difference in meaning between "injury by accident" (which means no more than "accidental injury": Hetherington v. Amalgamated Collieries of W.A. Ltd. [1939] HCA 36; (1939) 62 CLR 317, at p 325) and "injury caused by an accident" (which means injury the cause of which is an accident). The difference has been generally recognized: see Glasgow Coal Company, Limited v. Welsh (1916) 2 AC 1, at p 12; Columbia Cellulose v. Continental Casualty (1963) 40 DLR (2d) 297, at p 301; Smith v. British Pacific Life Insurance Co. (1965) 51 DLR (2d) 1, at pp 5-6; Mills v. Smith (1964) 1 QB 30, at pp 36,37-38; Federation Insurance Ltd. v. R. Banks [1984] VicRp 42; (1984) VR 525, at p 537. The difference is important in the present case because Mr Federico, suffering from no antecedent infirmity, has been injured while following his usual occupation of tiler, doing a job that he ordinarily did without injuring himself. He was not entitled to a sickness benefit and his entitlement to an injury benefit depends on whether his disabling injury was "caused by an accident".

5. A chain of causation will often lead back from a bodily injury to a cause which is not an accident. Even if a deliberate act is not itself the proximate cause of the bodily injury, a deliberate act may be a more remote cause which sets in train a series of events the last of which is the proximate cause of bodily injury. In the familiar case of a collision between motor vehicles, where the deliberate act of driving a car is a cause of an accident - the collision - from which injury results, nobody doubts that an injury suffered by a driver is "caused by an accident" though it is also caused, more remotely, by his deliberate act of driving. The rule in applying contracts of insurance is that the proximate cause of loss is alone regarded, as Lord Lindley pointed out in Fenton v. Thorley & Co., at p 455, and as Lord Loreburn L.C. affirmed in Clover, Clayton & Co., Limited v. Hughes (1910) AC 242, at p 245. But where an accident is a remote cause of a loss, the loss may nevertheless be regarded as caused by that accident. The ordinary consequences of an accident which are links in the chain of events causing a loss do not carry the loss outside the cover granted by a policy insuring against loss caused by an accident: In re Etherington and the Lancashire and Yorkshire Accident Insurance Company (1909) 1 KB 591, at pp 598,603.

6. Some accident policies cover death or bodily injury caused by "violent, accidental, external, and visible means". Under the present policy, which is not so limited, it is immaterial that the relevant "accident" is not violent, external, or visible. The policy definition of "injury" is satisfied by a proximate cause of bodily injury which is both accidental and internal. Provided "injury" is understood as covering a pathological condition caused by any accidental force or event, the cover which the policy provides is probably the cover which an uninstructed purchaser of the sickness and accident policy would have expected to obtain: a benefit is payable if the insured is totally disabled as the result of sickness or disease or any force or event that is unintended and unexpected or as the result of any combination of those causes. A benefit is not payable only if the proximate cause of the relevant bodily injury is a non-accidental force or event that is not itself the consequence of an accident.

7. Where a non-accidental act is a cause of bodily injury occasioning total disability, the insurer's liability therefore depends on whether the act is the proximate cause of the injury or whether the act produced an accidental consequence which is a more proximate cause of the injury. It is not necessary in this case to examine the proposition that a consequence of a deliberate act is an accident only if its occurrence is at once unintended and unexpected by the doer of the act and not reasonably to be expected by any ordinary person in his position (cf. per Kitto J. in Vallance v. The Queen [1961] HCA 42; (1961) 108 CLR 56, at p 65). The notion underlying the judgments of Samuels and Mahoney JJ.A. in National & General Insurance v. Chick (1984) 2 NSWLR 86, at pp 99,111-112 appears to be that such a consequence is accidental if it is both unintended and unexpected and not reasonably foreseeable. There was nothing in the evidence to suggest that Mr Federico, who was simply doing his normal work when he suffered his injury, should have foreseen that something would happen on the particular occasion to injure him.

8. However, where the condition of an insurer's liability is the occurrence of a loss "caused by an accident", it is not sufficient to show that the loss was unintended and unexpected; it must be shown that the non-accidental act produces an accidental consequence and that that consequence in turn causes the loss. In other words, there must be a link which is accidental in the chain of causation between a non-accidental act and the loss. There is no legal rule for identifying the links in a chain of causation and attributing to them an accidental or non-accidental character. It is a question of fact whether there is some link in the chain interposed between any non-accidental cause of an injury and the injury. It is a question of fact whether any such link is accidental. In Long v. Colonial Mutual Life Assurance Society, Ltd. (1931) NZLR 528, Kennedy J. said (at p 541):

" If a person suffering from a weakness or

disease should voluntarily subject himself to

conditions which would not injuriously affect

persons in ordinary health, but would be

dangerous to him, a resulting injury could not be

said to have been due to accidental means. But

if a voluntary act, which causes injury, is one

usually performed without injury and is not

calculated, in the ordinary course of things,

having regard to the conditions obtaining, to

produce the consequences which follow, some

fortuitous occurrence, which really caused the

unusual result, may be inferred."

With respect, I substantially agree. Where a person, who is not suffering from a bodily infirmity which exposes him to the material risk of injury, deliberately does an act which he is accustomed to perform without injury but suffers a traumatic injury as a result, it may be inferred in the absence of a more likely explanation that some unusual force must have been generated by doing the act and that the injury was caused by the application of that unusual force. If that inference is drawn, the application of unusual force is the proximate cause of the injury and, being an unintended and unexpected consequence of the act, it is an accident. This approach substantially accords with the judgment of Kaye J. in Federation Insurance Ltd. v. R. Banks from which I have derived much assistance.

9. Thus in Hamlyn v. Crown Accidental Insurance Company (1893) 1 QB 750, an insured bent down deliberately to pick up a rolling marble and wrenched his knee. The policy covered "any bodily injury caused by violent, accidental, external, and visible means". The insured was held entitled, Lord Esher M.R. saying (at p.753):

" He seems to have done this awkwardly; at all

events, in doing it he wrenched his knee, and

that did the mischief, and that wrench was the

cause of the injury. That that was accidental I

cannot doubt. He did not mean to wrench his

knee, and that would not be the ordinary result

of such an action."

" There cannot be a question that the means were

violent. They were also accidental, for getting

into the particular position in which the injury

could happen was not done on purpose."

Bray J. distinguished that case from the case before him in In re Scarr and General Accident Assurance Corporation (1905) 1 KB 387, at p 394:

" The plaintiff did not mean to wrench his knee,

and that would not be the ordinary result of such

an action. A.L. Smith L.J. says it was

accidental, for getting into the particular

position in which the injury would happen was not

done on purpose. I think I should have come to

the same conclusion. It was as if a man walking

stumbled and sprained his ankle. He did not

intend to stumble. The stumbling was accidental

and not the necessary or likely result of

walking. That would properly be called an

accident. There was no weakness of the knee or

other predisposing cause. Here, as I have said,

Scarr intended to violently exert himself, and

the injury to the heart followed as the natural

consequence. He never got into any position

which he did not intend. It seems to me very

like the case of a man with a weak heart injuring

it by running to catch a train. He intends to

run. Nobody would call such an event an

accident. No one would describe him as meeting

with an accident. Nor would any one in the

present case speak of Scarr as having met with an

accident. The question cannot, in my opinion,

depend on whether or not Scarr knew he had a

defective heart. If he knew that, he probably

would not have tried to eject the drunken man,

but that does not make the ejecting or the result

accidental."

10. A claim was dismissed in Clidero v. Scottish Accident Insurance Co.Limited (1892) 19 R.(Ct. of Sess.)355, where an overweight insured who bent over to put on his stockings displaced his colon and died. The policy covered death through "bodily injury caused by violent, accidental, external and visible means". Lord Adam said (at p.362):

" A person may do certain acts, the result of which

acts may produce unforeseen consequences, and may

produce what is commonly called accidental death,

but the means are exactly what the man intended

to use, and did use, and was prepared to use.

The means were not accidental, but the result

might be accidental. Now, if that is so, where

does the question of accident come in here?

There is no evidence, as your Lordship pointed

out, that anything unusual or exceptional

occurred as to the means or cause of this death.

The man was just doing what he meant to do, and

apparently a most unfortunate and unexpected

result happened, the man's death. On these

grounds I agree with your Lordship that there is

nothing violent in the sense of the policy to

account for this man's death."

11. In Hamlyn, the means by which the injury was caused was an unusual and exceptional consequence of the deliberate movement of bending over; in Scarr and Clidero, on the other hand, what the plaintiff was doing acted directly on an antecedent infirmity to cause the death of the insured. In Hamlyn, it was inferred that the plaintiff's injury was caused by a more proximate cause than the insured's deliberate movement and that that cause was accidental; not so in Scarr and Clidero. Federation Insurance Ltd. v. R. Banks falls into the Hamlyn category of case. There, the voluntary act of running between the wickets during a game of cricket caused a player's Achilles tendon to snap. It was inferred that "something occurred by chance" which, being unintentional and unexpected, was an accident causing the injury. By comparison, Dennis v. City Mutual Life Assurance Society Ltd. [1979] VicRp 9; (1979) VR 75, a case of deliberate strenuous effort acting on a diseased heart to cause death, falls into the Scarr and Clidero category.

12. In the present case, Mr Federico's levelling of the sand and cement mixture by use of a straight-edge was a non- accidental act, but it was an act which he was accustomed to perform without injury. He was not suffering from any antecedent infirmity, yet on the particular occasion he suffered the bodily injury which made him totally disabled. What could have caused it? Some extraordinary pressure must have been placed on his lower spine. It does not matter how it happened. As there was no antecedent infirmity of the spine, the proper inference to draw is that the processes of the spine yielded under an extraordinary pressure that was generated by Mr Federico's movement in levelling the sand and cement mixture. That inference might not be drawn if it appeared that Mr Federico's spine was infirm or that the levelling of a mixture of sand and cement ordinarily generated sufficient pressure to cause Mr Federico's injury. The evidence is against a theory that Mr Federico's spine was damaged by the pressure ordinarily generated by doing that work. As the placing of extraordinary pressure on the spine was unintended and unexpected, the proximate cause of Mr Federico's bodily injury was an accident. The learned trial judge did not find that an accident as I have described it actually occurred, but an inference that such an accident did occur should be drawn from the findings which his Honour made. It follows that Mr Federico is entitled to payment of injury benefit. The appeal should be dismissed.