"I know," I say, but, truly, are we familiar with this style? Can we imagine it in any sense, least of all adorning a physique that brings to mind one of Sybil Fawlty's greatest-ever put-downs of her husband - "ageing brilliantined stick-insect"?

Then there's the Waters moustache, itself fairly bug-like, which looks drawn-on but requires the most precise pruning every day. This all adds up to quite a vision, and Waters just carries on painting...

"My summer house is in Provincetown, Massachusetts, which is... how would I sum it up? A very remote gay fishing village. I'm on the top floor of a great beachhouse that's owned by the artist Pat De Groot, and because I'm right on the water it's like I'm living on a boat."

Edinburgh is about to welcome a director who is hailed as one of cinema's great anarchists. Waters' 'tache may evoke the memory of silent movie villains who tied damsels to train-tracks, but in his film Pink Flamingos he asked much more of his leading favourite drag queen Divine - eating dog poo.

That persona takes a bit of a knock, however, when the 61-year-old Waters reveals that I'm his "three o'clock". An incredibly fastidious man, he lives each day by a file of to-do cards. "Beach for one hour... Scotland On Sunday... maid comes... haircut... call my friend George... think of ad campaign for 'Pelt' party." This is an anarchist who leaves nothing to chance.

He asks about Edinburgh. I tell him it may not be quite outre enough for him, thinking this will cause him dismay, but quite the opposite. "Oddly enough, I get invited to lots of conservative towns," he says. "Before you guys, I'm going to Colorado Springs, home to that big mountain where they hide George Bush. It's also the headquarters of Focus On The Family, who are these crazy Christians. In these communities there are pockets of insane liberals and they're thrilled to be pissing off everyone else by inviting the likes of me.

"You know, I can get along with Republicans. If you can make someone laugh, they will listen to what you have to say. It's when you start talking politics that people switch off."

He's growing less freakish by the minute, but that's what sometimes happens to artists such as Waters. Their ideas, once so shocking, eventually get nicked by the mainstream - witness the new John Travolta/Michelle Pfeiffer version of Hairspray. (He loves it, by the way).

The day after our chat, a "scratch and sniff" window display is unveiled by Harvey Nichols to promote a new fragrance. It was Waters, though, who first made a film in "Odorama", the suburbia satire Polyester. "In every language, they paid me money to smell a fart," he says of the success of his first "overground" feature. "It's a universal urge."

Waters jokes about his new establishment credentials at the beginning of his Edinburgh-bound movie, This Filthy World. Directed by Curb Your Enthusiasm's Jeff Garlin, this is Waters on a stand-up tour of universities - ironic, since he was thrown out of every school he attended.

"This is my position paper, my vaudeville act," he says of the film, which shows no clips of his work as what William S Burroughs called "The Pope Of Trash" but relies on his (considerable) gifts as a comedian. Is there a message? "No," he says, "or maybe this: I'm a guarded optimist, even though I don't believe in an afterlife, and I don't think anyone is born evil. Don't judge others. Mind your own goddamn business."

Eavesdropping appears to be acceptable, however, and he passes on to his New York audience possibly the most damning piece of fashion criticism, the ultimate dressing-down of a dress: "That's so September 10."

This Filthy World does indeed go back to vaudeville, or what was left of it in Baltimore, Maryland, where Waters and Divine became childhood friends over a shared love of confrontational strippers who came onstage already naked.

There's a lot about death in it. How would he want to go? "Not in my sleep, that's for pussies. I want an airline crash, my hair on fire, and I'm struggling with the emergency door, having lied about not knowing how to open it so I could get a better seat. Plane crashes are always front page."

Waters' "unholy trinity" in his youth were Rhoda Penmark, the child murderer in The Bad Seed, Captain Hook (a rare male role model) and the witch in The Wizard Of Oz - "I was the only kid in the audience who didn't understand why Dorothy wanted to go home to that awful black-and-white farm when she could live among gay lions."

Elsewhere in This Filthy World, Waters pays tribute to the Z-movie directors who inspired him to make films, among them William Castle and Kroger Babb, who used rubber skeletons, electrical jolts and other gimmicks and medicine-show hoopla to create interest or, better still, hysteria for their flicks.

Is it more difficult to shock audiences now? "Well, I never set out to shock, that's easy. I've always tried to surprise people with humour on subject matter that makes them nervous. Even that scene in Pink Flamingos wasn't an attempt to shock. It was a reaction to pornography just becoming legalised in America. And it was only one take. I'm not a sadist."

So what shocks Waters? "Oh, lots of stuff. The barn-razing scene in Witness and when Forrest Gump starts running. Our community has standards too, you know.

"Any movies that are written by too many people - market-tested so much that no one likes them. And movies that are PC. I actually think I'm one of the most politically correct people I know."

He just might be. In This Filthy World he advocates: "We need to make books cool again. If you go home with someone tonight and they don't have books - don't f**k 'em." v

This Filthy World, Cineworld, Thursday and August 24 www.edfilmfest.org.uk