OVER the dark of the dance floor, the first thumping chords sail towards us. "Here it comes, here it comes," he says and he moves fractionally towards the bright stage, as if a step closer could make him hear better.

A big, urgent Scouse accent joins the guitar in song: "Well I heard a lovely rumour that Bette Midler had a tumour ..." It's Friday night, we're packed into the baking-hot Liquid Room in Edinburgh and for the first time in his life the prince of songwriting schmaltz, Dean Friedman, is listening to a band called Half Man Half Biscuit play the song that takes his name in vain.

Nigel Blackwell, the singer, speeds to the lyrical crux: "... and they reckon that I am, but I hope to God I'm not/ the bastard son of Dean Friedman." In front of us a tall middle-aged man is singing along lustily. Nearer the stage, young, late-flowering punks are pogoing as if there's no tomorrow. Biscuit - as the cognoscenti apparently call them - are independent and post-punk, a cult band with a huge following. "They're really melodic," reckons Friedman. "Boy, they sure know their genres," he adds as they rip into a country song.

By now things are getting lively and someone throws a bra at the band. When the singer takes on Bob Wilson, Anchorman Dean yells: "You'll have to explain some of these cultural reference points ..."

It's too hot, so we head to the courtyard for fresh air. Outside, Friedman remembers how he felt when he first heard The Bastard Son of Dean Friedman in 1987. "My wife was about to have our first child. For a couple of seconds I was real nervous; I was thinking, 'She's not gonna understand this one.'" He really thought it was true? "Well, I quickly figured out I'd have had to have sired him at the age of seven, so it wasn't possible. I relaxed. And it's a great song. There are so many funny lines ... I just feel bad for Bette Midler."

With his curly locks and his vintage moustache, Friedman was a man-sized version of Billy Joel, on the brink of world domination when his country duet Lucky Stars went to No 1 in Britain in 1977. The lyrics offered a humdrum scene of life - a couple arguing about his ex-girlfriend - which appealed to middle England and middle everywhere. That's exactly why the Biscuits hated it, wasn't it?

"Let me tell you something," says Friedman. "That guy Nigel was hip to the fact Lisa and I didn't just do lunch. You can't interpret a song that way unless you understand what it's about. And the bottom line is, under all his satire, Nigel is obviously a literate craftsman, who's probably as middle-class-normal as the rest of us."

As things turn out, he might be right. When we knock on the dressing-room door after the gig, it's as if a long-lost maiden aunt has come calling on the boys. They shuffle around with big vacant smiles, making smalltalk. "Everyone sang Lucky Stars in my school," recalls Nigel Blackwell, from the depths of a scabby old sofa. "I've got the Rocking Chair album, which is worth loads. You see it in rarity catalogues." "I wish I had a clean copy," Friedman says, a little wistfully. There are polite enquiries about what he's up to, where he's from (Paramus, New Jersey) and good wishes for his Fringe shows. But Blackwell has Lucky Stars in his head. He sings a line in broad Scouse: "Did you see Lisa," then he says, "when you say, 'No, I'm not being nice,' ... I like that bit."

It turns out the singer who dueted with Friedman on the song is called Denise Marsa. Blackwell's wife is called Denise and she shakes Dean's hand. "I should have introduced you before," mumbles Nigel.

We talk about Friedman's career. The guys didn't know he had been dropped by the industry for 17 years from 1981. It was because of his song McDonald's Girl, banned by the BBC. The Blenders later took it to No 1 in Norway. "We had a Norwegian hit," says Blackwell, reaching out for connections. "Stavanger Töestub."

There's more chat, before Friedman leaves the band to their rest and recuperation. "I really enjoyed tonight," he says at the door. Blackwell smiles again, and stretches out a hand: "Good luck with all the shows."

Back in the cool air, Friedman breathes out hard. "That was a little surreal," he says into space. "Did Nigel really say he had my album?" He did, he did.