My teenage son and I have had the talk. No, not the awkward one about contraception, but the one about consent. Much to my own surprise, I found myself telling him last week that when he goes to university he should think about getting his girlfriend (or hook-up, I guess) to say loudly and clearly, “Yes, I consent,” before every close encounter.

Even better, while larking about perhaps they could video each other agreeing to proceed on their mobile phones.

Paranoid? Moi? Not long ago I might have scoffed at such precautions. The world has gone insane, I’d have huffed, if healthy men and women need the sexual equivalent of a prenuptial agreement before getting it on. Now I worry the hour of madness is