Bottom 4 2001: An Arse Oddity; Barbican Centre, September 27, 7.30pm

Reflecting on the abiding popularity of Rik and Adrian, Edmondson says: "The secret is that we're out for a good time. On stage, we just want to generate hysteria. We don't care about looking cool or posing. We don't have any agenda, apart from 'Please laugh'. There are no rules - we just go from moment to moment trying to crank up the excitement."

Mayall is happy that Bottom is still defying the slings and arrows of the "metropolitan, middle-class media", believing the critics have missed the point. "People have trouble with it because comedy's been intellectualised about an awful lot during the last 15 years, but when you get down to it, all you're watching is a couple of guys being stupid and hitting each other. The French love us, of course. Its attraction is complete escapism," he says.

"Bottom is just a stupid, stupid cartoon full of stupid jokes told with tremendous panache. It's absolute b***ocks told in perfect rhythm."

To enjoy Bottom, Mayall suggests it is best to surrender to it. "You have to completely let go and swim in it. If you don't, it just looks like a collection of fart jokes - like jazz might look like a collection of notes. But if you immerse yourself in it and just go with the flow, it's there for your pleasure," he says.

Edmondson notes how critics thumb their noses at the Bottom act because it is neither intellectual humour nor Samuel Beckett. "Secretly, of course, we think we are two Samuel Becketts, showing up the very meaninglessness of existence. In its way, Bottom is not that different from Beckett's Waiting For Godot: two blokes are sitting around, hitting each other, waiting for nothing to happen."

Edmondson has a theory that "we all laugh when we witness other people's pain", as happens in Bottom. "It's called schadenfreude. What we're doing is wish fulfilment," he says. "Hitting someone with a spade without any consequences is something we'd all like to do. How many times have you sat fuming in a car, thinking 'I wish I had a machine-gun now'?"

Now in their mid-forties, Mayall and Edmondson retain their enthusiasm for their double act.

"We've always been rockers - that's our generation - and rockers never give up," says Mayall.

"They just keep rocking and expressing themselves and doing their thing. Ade's my partner. I may go off and have other adventures, but my greatest pleasure, my raison d'etre, has always been my double act with him. It's like that great line from Tom Stoppard: 'What happens to old actors?'. 'Nothing, they're still acting.' We'll never stop. We wouldn't know how to retire!"

That's the top and Bottom of it.

Fact file:

Name: Bottom 4 2001: An Arse Oddity

Occupation: Long-running comedy show, on BBC2 and on stage

Where, when and why in York: Barbican Centre, September 27, 7.30pm; first flash of Bottom on stage for four years

Partners in grime: Rik Mayall and Pocklington School old boy Adrian Edmondson, celebrating the 25th anniversary of a comic double act that began at Manchester University and has continued through 20th Century Coyote, The Young Ones, The Dangerous Brothers, Filthy, Rich & Catflap, Bottom and Hotel Paradiso

Bottom in brief: "Slapstick comedy on acid" involving two fighting, bottom-burping, sexually-frustrated losers in an explosively insane world. Dim-witted no-hopers Richie and Eddie, two pimples on life's bottom, survive on a diet of vitriol, mutually-inflicted wounds and pornographic magazines, as they belch, curse and smash their doomed way through the boredom of their hapless, hopeless lives

Bottom 4, the story: Trapped on Hooligan's Island, Richie and Eddie become embroiled in all sorts of surreal happenings

Bottom 4, the ingredients: One exploding parrot; one testicle cannon; one diagram entitled How To Remove Richie's Underpants With A Chainsaw; 478 gallons of illegal home-made super-strength banana and raisin ouzo; one scheme to get free pork scratchings from 'really itchy pigs'

Ticket update for York: Seats still available at £22.50 on 01904 656688.