In the second place, even if it could be said that he entertained an honest and reasonable belief that the club was a registered club entitled under the Act to sell liquor to its members, it could not in this case, in my opinion, be an answer to the charge. At this point the fact that the sale took place at 6.40 p.m., i.e. outside lawful trading hours for a club (see ss. 266 (2) and 8 of the Licensing Act 1928), becomes for the first time relevant. (Since the defendant was not charged with selling outside trading hours, it is not, in my opinion, relevant in any other respect.) If his belief had been true, the only result would have been that he was guilty of an offence under s. 266 of the Act. The rule as to the effect of an honest and reasonable mistake of fact means, I think, that such a belief excuses if its truth would have meant that no offence was being committed, not if its truth would have meant that some other and different offence was being committed. In the great case of Reg. v. Prince [1] , Brett J. said that a mistake excused "whenever the facts which are present to the prisoner's mind, and which he has reasonable ground to believe to be the facts, would, if true, make his acts no criminal offence at all " [2] . The judgment of Brett J. was the single dissenting judgment in a court of sixteen judges, but the whole point of the case is that the majority held that a mistake could not excuse unless the fact believed was such that, if it had been true, there would not merely have been no crime at all but no wrongful act at all. The statement of Brett J. is, therefore, to be regarded as stating a minimum requirement. Denman J. said: - "he cannot set up a legal defence by merely proving that he thought he was committing a different kind of wrong from that which in fact he was committing" [3] . The rule is generally stated in terms which mean that the existence of the fact mistakenly believed must be such as to render the act an innocent act; see, e.g. Bank of New South Wales v. Piper [4] . Kenny (Outlines of Criminal Law, 11th ed. (1922), p. 65), takes as an instance the case of a man who is charged with burglary, and proves that he honestly and on reasonable grounds believed that his breaking and entering occurred before 9 p.m. He would not be entitled to an acquittal on that ground, although, if his belief had been well founded, he would not have been guilty of burglary. In the present case the defendant said that he "did not know that trading hours for clubs were universally restricted to 6 p.m." But this, of course, is merely a statement that he did not know the law. If the facts established an offence against s. 161, the existence of a belief which, if well founded, would mean that his offence was not against s. 161 but against s. 266, affords him, in my opinion, no defence.