[37] Thus, an opinion as to whether conduct satisfies or falls short of a particular standard, such as whether particular conduct was in breach of a duty of care entails an examination as to what the expert's understanding is of the duty of care. Where the so-called opinion is proffered as to whether conduct satisfies or falls short of a statutory requirement, such as the Code, the expert must make clear just what his understanding of the effect of the Code might be. Unless the witness makes perfectly clear what he understands the Code to mean, his evidence as to whether particular conduct satisfies or falls short of it cannot be tested and can have no weight."
20 Mr McHugh submitted on behalf of the plaintiffs that the only real issue to be decided here is relevance. As he pointed out, s 56 lays down the general rule that all evidence that is relevant is admissible unless excluded by a provision of the Act. Section 80, as Mr McHugh pointed out, is not a provision that excludes. It is a provision that directs that there be no exclusion.
21 I accept Mr McHugh's submissions with one qualification. I would say that, consistently with the more recent authorities to which I have been referred, expert evidence cannot now be rejected just because it goes to the question of the application of a legal standard. But it can and must be rejected if it is not, in terms of s 79, wholly or substantially based on the expert's specialised knowledge, which is, in turn, based on the person's training, study or experience. And it can and must be rejected if it has no capacity rationally to affect the assessment of the probability of the existence of a fact in issue - they being the words in s 55 which define the concept of relevance.
22 One then comes back to the question the court will be required to determine in this case, that is, whether the use to which the land was put required the consent of any competent authority.
23 It is common ground that a large element of this will go to whether the activities on the land at relevant times were within the definition of "agriculture" contained in the planning instrument. The definition says that certain activities are included within the agriculture concept and certain others are excluded from it. One express inclusion is "horticulture". One express exclusion is "forestry". Between the express inclusions and the express exclusions, there is an undefined core concerned with "agriculture" according to its ordinary and natural meaning.
24 In general terms, a court does not need expert help to decide whether a particular activity on land is or is not agriculture or horticulture or forestry, any more than the court needs expert help to decide whether or not a particular portrait has been "painted": see Johansen v Art Gallery of New South Wales Trust [2006] NSWSC 577. The general principle is that the court does not need anyone's help to determine the meaning of an ordinary English word.
25 A threshold question, however, is whether one is dealing with an ordinary English word used as such or a word which, although it is an ordinary English word, is in the particular context not used as an ordinary English word. An example taken from Visa International Service Association v Reserve Bank of Australia [2003] FCA 977; (2003) 131 FCR 300 is the words "competition", "market" and "efficiency". All of these are words we use day by day in ordinary conversation. But they are words which, in the context under discussion in that case, had special meanings in the area of economics.
26 Mr McHugh says that the fact that "agriculture" is defined in the planning instrument sets it aside from its ordinary meaning and gives it a special meaning. I am not satisfied that this is so. There is, as I have said, a core which is, as it were, added to and subtracted from by a statement of particular things that are included and particular things that are not. None of the inclusions or exclusions can be said to involve anything more than ordinary English words. They are all readily understood activities that one knows when one sees them.
27 My conclusion is, therefore, that the court will not be assisted by Mr Glazebrook's views about what is or is not included within the defined concept of "agriculture", nor will it be assisted by his views about the meaning and operation of s 109. It is a provision concerning what is generally described as "existing use" or "continuing use" - a concept that was referred to in its legal signification in the judgment of McHugh JA in Royal Agricultural Society v Sydney City Council (1987) 61 LGRA 305 at 310:
"The effect of s 109, as it was interpreted in light of the High Court
decisions, was radically changed by the addition to it, operative from 3 February 1986, of subs (2). That subsection requires that "use" be understood in a much narrower sense than before; its effect was, in my opinion, to limit the continued use previously permitted by s 309 and s 109 without consent, to the actual use of the land on the day when the planning laws otherwise would have affected it, that actual use being confined to the land actually (as opposed to potentially) physically being used, and the extent
of the use of that land likewise being limited to its extent on that day."
28 When I say that the court will not be assisted, what I mean is that Mr Glazebrook's opinions on these matters do not have any probative capacity of the kind referred to in s 55, added to which neither the meaning of the relevant words nor the construction of the statutory provisions and those of the planning instrument is a matter of which it can be said that it lies within an expert town planner's specialised knowledge and which is, in turn, based on an expert town planner's training, study or experience.
29 The passages in question in Mr Glazebrook's reports will therefore be rejected.