R v Bree [2007] EWCA Crim 256, [2007] All ER (D) 412 (Mar)
The court considered the proper construction of s 74 of the Sexual Offences Act 2003: if, through drink (or for any other reason), the complainant has temporarily lost her capacity to choose whether to have intercourse on the relevant occasion, she is not consenting, and subject to questions about the defendant’s state of mind, if intercourse takes place, this amounts to rape.
However, where the complainant has voluntarily consumed even substantial quantities of alcohol, but nevertheless remains capable of choosing whether or not to have intercourse and, in drink agrees to do so, this does not amount to rape.
As a matter of practical reality, capacity to consent may evaporate well before a complainant becomes unconscious. Whether this is so or not depends on the actual state of mind of the individuals involved on the particular occasion.