Believe it or not, Mosley is fighting for freedom

The footage secretly shot by the News of the World looks like a softporn remake of 'Allo 'Allo, with silly German accents and high camp. The women involved are clearly enjoying themselves: one was a PhD student who told the court it "helped her to relax", while another joked she enjoyed it so much she should have paid Mosley.

But the News of the World's QC Mark Warby defended the newspaper's spying by pointing out this behaviour remains illegal. The cane used on Mosley, it is claimed, drew blood - and this is, under the current law, an assault. Warby told the court: "The law draws a line, and the reason is that sadomasochistic cruelty is contrary to civilised values and is corrupting of those involved."

This isn't a theoretical crime. In the early Nineties, 16 gay men filmed themselves engaging in consensual sadomasochism. The police spent £4 million of your money and mine investigating them, and the men went to prison. Since then, there have been at least four prosecutions along similar lines, including one of a married couple.

This is an unjustifiable assault on our liberty. John Stuart Mill said: "The only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others. His own good is not sufficient." If you are sane and you want to harm yourself - with booze or fags or whips - it's up to you.

And sadomasochists are as sane as the rest of us. The psychologist Pamela Stephenson Connolly says she has found they are no more likely to be depressed or insane than you or me.

It doesn't appeal to me but it seems to be a way some people leech out their anger or lack of control. Fine. Let them. There is an easy solution to this legal nonsense. In Britain, you are currently allowed to consent to injury in four specific situations: sport, surgery, piercing and circus performing. Why not add sadomasochistic sex?

Mosley's eloquent defence of himself from the witness box should never have to be offered again. This case should be the Wilde trial for sadomasochists, a moment to say - enough.

I never thought I'd type these words but, for today, Max Mosley is a freedom fighter.