Mistake of Law and of Fact
Mistake of Law
There is a general rule that ignorance of the criminal law is no defence, even if the ignorance is reasonable in the circumstances. For example, see: R v Reid (Philip), where a constable saw the defendant driving a car without a tax disc. He stopped the defendant and then noticed that the defendant’s breath smelt of drink. The defendant refused to provide a specimen stating that the constable had no power to administer a breath test except after an accident, where there had been a moving traffic offence or where the constable had reasonable cause to believe from the manner of his driving that the driver had been drinking. The defendant was convicted of failing, without reasonable excuse, to provide a specimen for a laboratory test, contrary to s3(3) of the Road Safety Act 1967. The Court of Appeal held that the fact that the defendant mistakenly believed that he was not legally obliged to provide a specimen did not constitute a ‘reasonable excuse’ for refusing to do so.
By way of contrast to a mistake of criminal law, a mistake of civil law can quite easily provide a defence to a criminal charge, provided the actus reus of the offence involves proof of a legal concept. See: R v Smith (1974).
Mistake of Fact
A mistake of fact will be a complete defence, resulting in an acquittal, where it prevents the defendant from forming the mens rea of a crime. See: DPP v Morgan, where the defendants were members of the RAF. Morgan invited the three other defendants to his house and suggested to them that they should all have intercourse with his wife. He told them to expect some show of resistance on his wife’s part but that it was mere pretence whereby she stimulated her own sexual excitement. The three younger men were convicted of rape and aiding and abetting rape despite their contentions that they had believed the victim to have been consenting to sexual intercourse and Morgan was convicted of aiding and abetting rape. They appealed against the trial judge’s direction that a belief that Mrs Morgan consented must have been honestly and reasonably held. The House of Lords, by a majority of three to two, held that a defendant was to be judged on the facts as he honestly believed them to be, and thus a mistake of fact would afford a defence no matter how unreasonable it might be provided that it was honestly made. However, the House of Lords dismissed the appeals as the jury obviously considered that the defendants’ evidence as to the part played by Mrs Morgan was a pack of lies (per Lord Cross).
Drunken Mistake
Where a defendant’s mistake of fact arises from self-induced intoxication, it will only provide a defence to crimes of specific intent. See: Fotheringham, where the defendant had been out drinking, got into bed and forced the baby-sitter (who had fallen asleep in the bed) to have sexual intercourse. He claimed that he was so drunk that he thought the girl was his wife. The Court of Appeal held that (1) self-induced intoxication cannot be used as a defence to a crime of basic intent and stated that (2) neither could the defence of mistake be raised, if this mistake were caused by self-induced intoxication: O’Grady.