Ah, the old "not enough information" defense.
Sorry to repost, but as jinx couldn't be arse reading the thread:
Yale
"Definition of Sexual Consent
Sexual activity requires consent, which is defined as clear, unambiguous, and voluntary agreement between the participants to engage in specific sexual activity. Consent cannot be inferred from the absence of a "no"; a clear "yes," verbal or otherwise, is necessary. Although consent does not need to be verbal, verbal communication is the most reliable form of asking for and gauging consent, and individuals are thus urged to seek consent in verbal form. Talking with sexual partners about desires and limits may seem awkward, but serves as the basis for positive sexual experiences shaped by mutual willingness and respect.
Consent cannot be obtained from someone who is asleep or otherwise mentally or physically incapacitated, whether due to alcohol, drugs, or some other condition. Consent cannot be obtained by threat, coercion, or force. Agreement given under such conditions does not constitute consent.
Consent must be clear and unambiguous for each participant throughout any sexual encounter. Consent to some sexual acts does not imply consent to others, nor does past consent to a given act imply ongoing or future consent. Consent can be revoked at any time. For all of these reasons, sexual partners must evaluate consent in an ongoing fashion and should communicate clearly with each other throughout any sexual encounter."
See also Rape Crisis' definition of rape - take particular note of:
"It is not relevant what relationship, if any, a defendant has or had with you. Nor is it relevant if the act complained of occurred within a relationship. If the defendant intentionally penetrates with his penis the vagina, anus or mouth of the complainant without her consent where he does not reasonably believe in her consent the defendant has committed rape."
And also a recent review on consent, Telegraph article here
In what ministers regard as its crucial paragraph, Sir Igor said: "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 would be rape."
Personally I like the way Yale put it best, but it all amounts to the same thing.
Links are upthread, I need to make lunch.....