Jamieson v HM Advocate is a notable legal case which established a precedent in Scotland which held that a man does not commit rape where he honestly, albeit unreasonably, believes his victim is consenting.
[1] The decision relies upon the point that in Scots Law, a criminal act consists of two elements, the factual act done and the mens rea or intention of the perpetrator in carrying out that action.
Accordingly, it was held that if the man genuinely believes the woman is consenting, he is not committing the specific crime of rape.
The decision was that honest belief is all that is required, although an absence of reasonable grounds to hold such a belief would affect whether a jury would accept if as a matter of fact he did genuinely believe this.
This precedent is unlikely to be considered as still 'good law' as the Sexual Offences (Scotland) Act 2009 (which provided the first statutory definition of rape and of consent) states at S.1 (1)(b) that [a person 'A' commits rape upon 'B'] "(b)without any reasonable belief that B consents".