//
© 2026 Zoe. All rights reserved.
Zoe is a legal information platform. Always consult the Federal Register of Legislation for authoritative text.
[1996] NSWLEC 265
Land and Environment Court (NSW)
1996-11-21
Judge Pearlman J, Pearlman J
Original judgment source is linked above.
The application of the defence of honest and reasonable mistake of fact in the prosecution of an offence under the Clean Waters Act 1961 was comprehensively considered by Gleeson CJ in State Rail Authority of New South Wales v Hunter Water Board (1992) 28 NSWLR 721. Although that decision was concerned with a different offence to that which is the subject of these proceedings, the matter with which both that offence and this offence are concerned is pollution of the environment. Accordingly, I respectfully adopt the following propositions (which are set out at p 725) as applicable in this case:
� the state of knowledge or information or understanding which will constitute a relevantly mistaken belief is to be described by reference to the particular context in which the problem arises;
� a mere lack of knowledge that pollution was occurring, or was likely to occur, based upon a general understanding or assumption that everything was in order, would not be sufficient to amount to a mistaken belief;
� what is required is "a positive belief that the operation of the plant and equipment would not result in pollution";
� that belief "would also need to be sufficiently specific to relate it to the elements of the particular offence".
In this case, the fact in which Mr Mant Snr had an honest and reasonable belief was that the truck was in good working order, having been maintained carefully and adequately. However, that fact is not sufficient to take the defendant's act outside the statutory enactment. The Clean Air Act says nothing about the maintenance of vehicles; it deals with the emission of excessive air impurities. Mr Mant Snr made an assumption based on the fact in which he believed, namely, that because the truck was in good working order, it would not emit excessive black smoke. However, that is an assumption, not a fact. (Based on Mr Hall's evidence, it is also an incorrect assumption, but nothing turns on that). Having regard to the principles which I have set out, more is required to excuse the defendant than a general assumption that the truck was in good working order. What is required is a positive belief that some element of the construction or operation of the truck was such that the truck could not emit excessive black smoke. An assumption based on the belief that the truck was in good working order is not sufficient to exonerate the defendant from culpability.
I conclude that the defence of honest and reasonable mistake of fact has not been established.
For the reasons which I have set out, I have concluded that the appeal should be dismissed.
There was no issue as to the appropriateness of the fine which was imposed, nor as to the amount of costs ordered in the Local Court.
I propose to make no order as to the costs of this appeal, no submissions having been made to me in relation to costs. However, I will grant liberty to apply within seven days on the question of costs of the appeal.
I HEREBY CERTIFY THAT THIS AND THE PRECEDING 14 PAGES ARE A TRUE AND ACCURATE RECORD OF THE REASONS FOR JUDGMENT HEREIN OF THE HONOURABLE JUSTICE M L PEARLMAN AM.
impurities - Proudman
Dayman defence - honest and
The defendant relied, in exoneration of culpability, on the defence of honest and reasonable mistake. That defence excuses a defendant if he or she had an honest and reasonable belief in a state of facts which, if they existed, would make the defendant's act innocent (Proudman v Dayman [1941] HCA 28; (1941) 67 CLR 536 at 540).
(1941) 67 CLR 536
(1992) 29 NSWLR 497
(1992) 28 NSWLR 721