'It was a dreadful four or five days,' laments Jude Finisterra alias Andy Bichlbaum, who is crouched over a restorative gin and tonic in the corner of a Covent Garden hotel a week later, looking beleaguered and exhausted. 'Not sleeping, feeling guilty as hell. I kept wishing it would just blow over. It was,' he sighs, 'the absolute worst.'

What the hell did he expect, though, I ask, given the high risk factor involved in such a confrontational strategy? Surely they had thought through the possible ramifications beforehand: the raising of false hopes, the playing around with victims' emotions? 'Yeah, of course,' he replies not altogether convincingly, 'but we thought it would take Dow maybe five or 10 minutes to respond. I actually thought I'd be pulled off the air during my speech. But two hours? I mean, come on.'

His partner, Mike Bonanno, who has just slipped into the seat beside him, takes up the case for the defence. 'A full two hours for Dow to retract,' he repeats, sounding indignant, 'So it was their fault in a way. They should have retracted immediately.'

It turns out that this new bullish mood is down to the emails and messages of support the Yes Men have received in the intervening week, including many, they claim, from Bhopal activists on the ground. 'If you had interviewed us last Saturday, you would have found us crushed by guilt,' admits Bichlbaum. 'We would probably have told you that we should have done it differently, but now, thinking of how the response has changed from the purely negative to the mostly positive, I'm not so sure.' Bonanno nods in agreement. 'It focused so much attention on Bhopal and Dow's attitude that it was worth it. Believe me, the anniversary would have passed without any media attention at all in America.' As if on cue, Bichlbaum takes over again. 'And that would have backed up Dow's whole attitude - "They died, we won, game over" - so, in a way, even with the false hopes issue, it was a successful intervention.'

The Yes Men are in town, as it happens, to promote their forthcoming film of the same name, a documentary record of some of their more sustained campaigns of political mischief, which is released in Britain in February. Their film company's planned two-day pre-publicity schedule has been turned upside down by the fallout of what is now referred to by the two as 'the Bhopal incident', and they both look bedraggled by the experience.

Bonanno and Bichlbaum, which they insist are their real names, are a double act in every sense. They share what might be called a well groomed, preppie look and a geeky sense of humour, their to-and-fro conversation peppered by words such as 'wonkish', which I'm not sure even they know the meaning of. One suspects they could become quite annoying quite quickly if their nebbish prankster tendencies were not tempered by a political streak that is as radical as it is mischievous. They both grew up in what they term 'left-liberal Jewish families', Bonanno in upstate New York, Bichlbaum in Tucson, Arizona. They met eight years ago, having been involved individually in anti-global activities of the more absurdist variety. Their stunts often emerge out of the many fake websites they have set up, all of which bear a striking resemblance to the real thing, so much so that they are constantly being invited to participate in right-wing think-tanks and corporate conferences of the most market-driven type. Their most effective lookalike site to date has been gwbush.com, which concentrates on the teenage GW's much-contested recreational pursuits. 'This guy's just a garbage man,' was Bush's verdict when asked about the fake site during a press conference.

Since then, the Yes Men have built a similar site satirising the World Trade Organisation, one of their corporate pet hates, and have been invited to give some seriously deranged PowerPoint presentations by unwitting corporations. Many of these performances feature in the Yes Men film, directed fly-on-the-wall style by Chris Smith, who made the brilliant fake documentary American Movie in 1999. His camera wanders over the glazed faces of conference goers and World Trade Organisation employees as Bichlbaum, under the pseudonym Hank Hardie Unruh, advocates the return of indentured slaves as a way around petty trade restrictions such as the minimum wage, and the creation of a recyclable third-world burger made from refined human waste which could be eaten a total of 10 times.

Often, towards the culmination of a presentation, Bonanno will rip off Bichlbaum's grey suit to reveal a shiny, gold, body-hugging 'management leisure suit', complete with a huge inflatable phallus which features an inbuilt satellite camera that can be deployed for keeping tabs on a company's global workforce. As the film shows, this advanced absurdism often meets with a remarkably approving response, though most of the time, you feel that the general torpor of the conference circuit may have dulled the senses of the participants to the point where they have simply zoned out.

'Nothing surprises me about business people any more,' says Bichlbaum wearily. 'It's fascinating how gullible they are, and quite fantastic in a way. That's why theatre and film work, after all, and it's certainly why politics and corporate power works. People will believe anything if it is told by someone in authority. The Republicans rely on, and exploit, that passivity more than most, but so do all political parties. We see ourselves as a kind of indignant but mischievous opposition to all that.'

To this end, they dogged the footsteps of the Bush campaign in a customised bus bearing the words 'The End is Near' and a devilish GW with a giant missile where his nose should be. They also collected thousands of signatures from diehard Republicans for a petition to increase global warming. How do they respond to the charge that they are not elected representatives, that they are, in fact, loose cannons exploiting the very freedoms that democracy allows by impersonation, hoaxing and, some would say, conning corporate targets? 'Well, who elected the World Trade Organisation?' responds Bonanno. 'It was created by an elite for an elite. It serves no one but that elite, and its whole attitude to the so-called Third World is colonial'.

Both Bonanno and Bichlbaum now consider the Yes Men their full-time job, and have been funded by some unlikely sources including an art foundation set up by the erstwhile musician and retired head of A&M Records Herb Alpert. 'It was more an award for conceptual art rather than political activism,' says Bonanno, 'and we were chosen by the artists on the awards panel rather than by Herb himself. He said something like, "I don't understand it, and it's pretty weird, but its kinda hep." We took that as a thumbs-up.'

So it goes. Somewhere between satire and surrealism, activism and absurdism, the Yes Men seem likely to wreak embarrassment and confusion for some time to come, and not even the censure that followed the 'Bhopal incident' seems to have dimmed their determination. 'We may seem entirely mischievous, but we are in fact deadly serious,' says Bichlbaum. 'We both had grandparents who died in the Holocaust so we share an inbuilt suspicion of power, and a healthy fear of the places it can lead to if the powerful are left unchecked. That has transferred itself into a refusal to take those in power seriously, but it doesn't mean we are not serious in our goals.' And how would he summarise those goals? 'To make the world a better and a fairer place. The left have to get smart again, to become a valid opposition. This notion propagated by New Labour that there is some third way beyond politics that will consign the left-right division to the dustbin of history is nonsense. It's delusional.'

If I were Tony or Gordon, I'd keep an eye out for smooth talking infiltrators in the run-up to the election. It's surely only a matter time before that shiny gold inflatable phallus makes a very public appearance on these shores.