The Tiger Lillies: Funny. Peculiar.

'We're a famous people's band," says Martyn Jacques, the founder, writer and frontman of the Tiger Lillies, in the dressing room of the Komedia, a cabaret bar in Brighton. "We're not famous, but famous artists are fans of ours, people like Mel Brooks, Barry Humphries... what's the guy from The Simpsons?" Adrian Stout, the bass player, who despite his name is rather thin, supplies the name of Matt Groening.

"Matt Groening," continues Jacques. "Terry Gilliam. All these weird radical people. Marilyn Manson. It's very gratifying. We might not be famous, but we've got famous fans. Ha ha! Through a mixture of chance, luck and design, we've managed to stumble on to a vein almost of our own."

One might take issue with that "almost", for no one else does what the Tiger Lillies do. Jacques calls their performance "Brechtian punk cabaret", which is fair enough, but any number of acts on the Edinburgh fringe would probably describe themselves in those terms, and the Tigers are unique. In greasepaint and eccentric evening dress, accompanied by Stouton double bass and saw, by Adrian Huge (who is on the large side) on various percussion instruments, and by himself on accordion and keyboards, Jacques croons, warbles and shrieks his way through a repertoire of remarkable perversity, encompassing every conceivable neurosis and vice, and some that are almost beyond conception. (If you don't know their albums, there's a fair chance you saw them a few years ago providing grotesque musical accompaniment to dramatisation of the uncanny, cautionary tales of Heinrick Hoffman in the West End show Shockheaded Peter.)

Their album Farmyard Filth (1997) for example, is billed as "possibly the most extensive collection of songs dealing with zoophilia in recorded history". To tunes that owe much to music hall, by turns jaunty, rousing and wistful, the Tigers sing, among other things, of blasphemy, rape and matricide, and currently tackle all three of those subjects in the same song. After a recent performance in Hamburg, Jacques was approached by a German psychiatrist who said, "It's amazing how you manage to get absolutely everything in."

"We tend to do a lot of touring," Jacques explains, "because the kind of music we make doesn't really sell that many records. We've made a lot" - 16, so far, all for the Misery Guts label - "but we don't sell many, do we?" The other Tigers nod their agreement. "We're a marketing man's nightmare," says Stout cheerfully, and they all cackle.

Jacques sings in a falsetto of remarkable purity and range, almost like a classical castrato. "I'm a counter-tenor," he says. "I lived in Soho, and I didn't really work much through my twenties, but I used to go to the City Lit, and in the old days you could go there and do as many courses as you wanted, if you were unemployed, for something like 70p a year. So I used to do classical singing classes and jazz singing, that's the limits of my study.

"I was singing all different styles - Louis Armstrong, Lou Reed, and like a tenor - not particularly well, probably, but anyway I was practising. And when I was about 30 I got an accordion, and I thought, 'I know what I'll do, I'll play the accordion and sing in a high voice, and that'll be very original, and I'll make millions.' That's what I thought, and I was wrong. Ha! Here we are, 17 years later, in the Komedia, playing to 160 people. There you go, that's life. But anyway, we make a living."

Jacques grew up in Slough, and in one of his songs he concurs with John Betjeman's opinion of the place: "Well it's grim up north / But it's grimmer than that in Slough / I'll sing you a song / If you drop a bomb on Slough."

He left to read theology and philosophy at Lampeter but, though he has retained his interest in those subjects, he dropped out after a year to live in a squat in Finsbury Park, an unlovely suburb of London. "Next door to me was a very attractive young woman," he recalls, "who worked in the peep shows in Soho - probably why I ended up there. She was a speed freak but she was very artistic, and when I got an old Dansette record player she gave me The Threepenny Opera by Brecht and Weil, Small Change by Tom Waits and a record by the Birthday Party, which was Nick Cave's band - another interesting artist. I particularly loved The Threepenny Opera, with Lotte Lenya singing in German. I loved the instrumentation, and the pump organs, and that was probably my biggest musical inspiration."

In 2001, the Tigers released the album 2 Penny Opera ("It's one cheaper"), featuring such songs as "Bitch", "Bastard" and "Piss on your grave".

The biggest inspiration in terms of subject matter is Jacques' sojourn in Soho, where he lived above a clip joint or semi-brothel. "I had a market stall for a while, selling marijuana-smoking paraphernalia - chillums and pipes - with two other strange men. One of them was an old jailbird and druggie, and the other used to have birds singing on a ghetto blaster.

"This market stall was beautiful, covered in flowers, like an altar, with birds whistling, like a little jewel in the middle of Rupert Street, and the other stallholders were freaked out. But we did all right, for a while. I could see my stall from my window, and my girlfriend used to work in one of the clip joints.

"There were also heroin dealers living downstairs. One day, I heard this blood-curdling scream in the street, and this scream started coming up the stairs, and went into the room underneath me. I went down and the dealer had his face cut from cheek to cheek. Obviously a Triad, heroin thing. So it wasn't necessarily great, but from a song-writing point of view it was good material.

"I knew all the junkies and prostitutes, and I'd be hanging out in illegal drinking dens until four in the morning with all these weird people. It was a good life, and very inspiring for me, because later, when I formed the Tiger Lillies, I used a lot of this stuff. I always think of Toulouse-Lautrec, hanging round in brothels. I think for an artist it's good experience."

How did the band start? "I got the accordion, started singing in a high voice, put an advert in the Melody Maker, and somebody answered who was a friend of Adrian's [Huge, whose real name is Hughes], and he said he had a friend who played with brushes, so he got the job. The bass player couldn't play in tune, so I had to sack him half way through our first recording session. I got another friend to play bass for about six years, and then he married and went to live in a forest, so then Adrian [Stout] came, and has been in the band for 10 years."

Where did the name come from? "There was a prostitute called Tiger Lily, who wore lots of tiger skin, so it's sleazy. And there's the flower. And it's a play with the beautiful and the strong. And the lily is death, as well, and we sing about death a lot. It's hard music, I suppose, heavy and dark."

It is. Sometimes funny, and sometimes tender, it is consistently raw and often disturbing. The lyrics are inevitably flat without the music, but to give a flavour, here is the opening of "Smell": "I saw the piss running down your leg / I knew that you were not well / I saw the vomit come out of your mouth / And I knew that you were in hell/ And I love you though you smell."

"People can get upset," says Stout. "It tends to hit them in unusual ways sometimes. It's quite emotional. It's designed to create tension and confusion. It's not an easy evening or easy music. We challenge and disorientate the audience, we don't expect them to be wholly happy. We have to maintain the tension. The whole thing is about ambiguity."

"We had people in Germany the other day," observes Huge, in his only contribution to the conversation, "saying they thought we were all women."

"We did a show in Belfast," says Stout, "and there was a small accident. A trapdoor was left open on the stage and Martyn fell through it. Someone came up to me after the show and asked [in an Irish accent]: 'Was that woman all right? Was she hurt at all?' There's a confusion sometimes, which is not a bad thing."

"Compared to the Old Masters in the National Gallery," says Jacques, "I'm a complete pussy. The blood, the rape and so on, all that cruelty and inhumanity. And it's going on now, as we speak, in Iraq. If I manage to shock, then I'm succeeding in my aim."

The Tiger Lilies will next play at the Soho Theatre, 21 Dean Street, London W1, 18 May to 3 June (0870 429 6883). For more information go to www.tigerlillies.com