Correct on the date of publication - 13 October 2025
Question:
Is it possible to raise a defence of a mistake as to fact or law?
Answer:
It can be a defence if a person makes an honest mistake as to certain facts causing him/her to take a course of action which, on the surface, appears to be an offence. For example, a defendant's genuine mistake as to the identity of a county court bailiff, whom he thinks is an attacker and therefore assaults him (Blackburn v Bowering 1994).
Note section 2(1)(a) of the Theft Act 1968 which states that if a defendant appropriates property in the belief that he has in law the right to deprive the other of it, on behalf of himself or of a third person, he will not be regarded as dishonest. This belief could be based on a 'mistake' and has the effect of negating mens rea for the criminal offence of theft. The same would apply to a mistaken belief as to ownership of property as a defence to a charge of Criminal Damage. Section 5 of the Criminal Damage Act provides a specific defence for this that can include a belief in a 'lawful excuse' to cause damage that is based on a mistake.
There is no presumption that everyone knows the law, but it is generally no defence for a person to argue that their ignorance of the law is an excuse. Even for example where the defendant is a foreigner and can show that the offence is not criminal in their own Country, this will not relieve him of liability and conviction in the United Kingdom.
This concept that 'ignorance of the law is no excuse' was summed up in R v Bentley 1850 when the judge stated in his judgement:
"I think that, to support a charge of resisting a lawful apprehension, it is enough that the prisoner is lawfully apprehended, and it is his determination to resist it. If the apprehension is in point of fact lawful, we are not permitted to consider the question, whether or not he believed it to be so, because that would lead to infinite niceties of discrimination. The rule is not, that a man is always presumed to know the law, but that no man shall be excused for an unlawful act from his ignorance of the law. It was the prisoner's duty, whatever might be the consciousness of innocence, to go to the station-house and hear the precise accusation against him. He is not to erect a tribunal in his own mind to decide whether he was legally arrested or not. He was taken into custody by an officer of the law, and it was his duty to obey the law".
This principle was strongly supported by the Queens Bench Divisional Court in Hewitt v DPP (2002).
View the full Legal Q&A document here, with links to related and similar legal questions.
For quick and easy access in the future, click the pin icon from the top right of any document to save it to 'My Documents'.
