enjoyed the fun. Bondage. Pretend rapes. The works. We were hooked, I think, on the drug that violent sex provides - the endorphin rush.

So maybe it was no surprise that one day these dangerous games got out of hand. We were blurring the moral boundaries: we were asking for trouble. And in the end we both paid a heavy price - my girlfriend felt violated and angry, I did two months in prison on remand.

Following my acquittal I wrote a novel about dangerous sex. By way of research for the book I attended many trials of 'sex crimes'.

Many of these cases were simple rapes. Horrible but basic. But more than a few came from the blurred and sinister area of sexual games and experiments gone awry. Rich young couples who strangled each other - 'scarfing'.

Swinging sex that ended in jealous violence. Games of submission and domination where a little too much blood was drawn.

The lesson I learned from this is that, as a society, we now treat sex too lightly. We see