The Mission: Will bungee-jumping push Nicholas Barber over the edge? Well, that's the general idea ...

he UK Bungee Club is based in Adrenalin Village, a Portakabin shanty town next door to Battersea Power Station in south London. Its inhabitants - the Adrenalin Village people - are unshaven, long-haired young men in fleeces, Aviator shades and No Fear baseball caps. In short, they are Australians.

For me, a Lots Of Fear baseball cap would have been more suitable. The presentation of a waiver averring that "bungee jumping ... involves the risk of death or bodily injury" is very nearly enough to make me back out. Resisting the urge to score out the word "death", I sign my name in quivering letters.

In the shadow of a 300ft crane - claimed to be the world's tallest bungee tower - I'm kitted out for my leap of faith. One harness loops through my legs and round my waist. An Australian fastens it pinchingly tight, but I stop myself complaining in the nick of time. Asking to be attached to a breathtakingly high platform less securely would quite rightly get me disqualified on grounds of gross stupidity.

Another harness goes round both ankles, which are strapped together. This is no doubt an important safety measure, but I can't help thinking that its main purpose is to prevent me running away, as I am sorely tempted to do. As far as I can see, all that's missing is the inflatable crash mat which will cushion my fall if the rope snaps.

Then the Australian explains that the crash mat is already in place: it's called the river Thames.

I shuffle into a cage the size of a small lift - which is, in effect, what it is. The bungee rope is connected. Along for the ride are Graham, the Jump Master (which must make me the Jump Slave), and another man with a camera on his shoulder, who is filming a souvenir video for me. His presence will turn out to be absolutely vital.

Within half a minute, the crane has winched us high above the rooftops of London and swung us out over the river.

I can see the Millennium Dome in the distance. I wonder if I'll live to see its completion. I can see a boat moored below me, so close by that I'm afraid I may soon be headbutting its roof. Graham opens the gate.

I can't move. The Pepsi Max commercials were never like this. If you want to know how it feels to stand on a ledge, 300ft up, with a rubber band tied to your ankle, simply imagine standing on a ledge, 300ft up, without a rubber band tied to your ankle. A primal survival instinct insists that stepping off is not a sensible idea. Then I realise that if I hesitate now, my moments of shame will be recorded for ever on video. Vanity beats sanity, and I dive forward.

It's a rollercoaster times 10: fast, frightening, exhilarating and supremely disorienting. "You're not supposed to be this way up!" screams my instinct. I bounce half a dozen times as the crane swings over solid ground again and lowers the cage.

Underneath me, two Australians scurry back and forth, ready to pull me down to safety, like Laurel and Hardy waiting to catch a piano. I'm grinning from ear to ear. But I have to say that the G-force on my face has a lot to do with it

UK Bungee Club (0171-720 9496)