Can a licensed victualler quash a conviction for supplying alcohol to a police constable while off duty?

In Sherras v. De Rutzen, [1895] 1 Q.B. 918, s.16(2) of the Licensing Act prohibited licensed victuallers from supplying liquor to police constables while on duty. It was held that as the licensed victualler bona fide believed that the police constable was off duty, and that there were reasonable grounds for that belief, that the conviction should be quashed. In that case Wright J. at p. 921 said: “There are many cases on the subject, and it is not very easy to reconcile them. There is a presumption that mens rea, an evil intention, or a knowledge of the wrongfulness of the act, is an essential ingredient in every offence; but that presumption is liable to be displaced either by the words of the statute creating the offence or by the subject-matter with which it deals, and both must be considered.”