My understanding is that this revolves around section 74 of the Sexual Offences Act 2003: which states that consent requires agreement by choice, and freedom and capacity to make that choice.
So if a woman pretends to be a man to have sex with me, using a prosthetic, when I thought she was a man with an actual penis - I haven't consented and that is a sexual offence. That seems right to me.
On this basis, though, I don't understand why the plain clothes officers who had sex with women as part of their cover haven't already been prosecuted. Surely these were sexual offences? (I think these men need to be prosecuted - what they did was vile sexual exploitation; their victims had no chance to consent in any meaningful way.)
I do worry though about where to draw the line. Say I meet a man and tell him I have no children -whereas in fact I'm a single mother. Does that remove his capacity to consent? Or if I tell him I'm a Labour voter, when in fact I'm a committed Tory. Does that? (In neither of these cases do I think this should be a criminal offence.)
How about if a man tells me he's single, whereas in fact he's married? (He's a pig, but I don't think he should be criminalised - but then I'm not a committed Christian. Maybe if I was this would be so utterly fundamental to me that it would cause me huge trauma. Is that relevant?)
I suppose what I'm getting at is that I think for law to work properly there needs to be a way to draw a line - criminal acts on one side, legal (even if deplorable) on the other. And a way for people to tell which side of the line they're on. Sometimes this line is arbitrary (for instance the age of consent)- that doesn't matter, so much as the fact that it's there, and is easily identifiable. What is the line when it comes to sex and deceit? And what should it be? When should deceit negate consent? Can a bright line ever be drawn?