Lord Melvyn Bragg has flung open the gate of terrestrial television’s last remaining temple of culture and welcomed in a former heroin addict who sometimes physically attacked his own audiences, and whose only chart hit was accompanied by a video depicting him murdering Kylie Minogue. Tonight’s South Bank Show features the Australian singer-songwriter Nick Cave. His quarter century career has encompassed the chaotic post-punk of The Boys Next Door and The Birthday Party, the acclaimed novel And The Ass Saw The Angel, and the epic sounds of Nick Cave and The Bad Seeds. But the programme makes a case for the former punk icon as an artist at the height of his powers, and, most endearingly, opens with Lord Melvyn himself, standing in a field, describing Cave’s early work as ‘an orgy of violence’. The show has a pleasing absence of both tabloid tale telling and critical analysis. Perhaps Cave has attained a dignity that makes such intrusions irrelevant. In the year that Mick Jagger, an eternal adolescent, turns sixty, Cave has somehow arrived in his mid-forties as his polar opposite – a middle-aged rock star who is not remotely embarrassing.

Cave’s vast press pack documents the changing journalistic angles used to appraise him. Once his struggles with various demons, both chemical and personal, were used to explain the violence of his music. But in the light of the reflective timbre of the records he’s made since 1997’s The Boatman’s Call, Cave is depicted in his Brighton domestic idyll, travelling to his office everyday, sitting at the piano, refining his craft. “I don’t really read pieces about me but I get the feeling they’re all exactly the same,” he explains, “That must be tedious for my fans. But my fans are very forgiving. They’ve forgiven me for my years of drug addiction, and for my dubious Christian leanings. But they probably wouldn’t forgive the fact that today I am wearing Hi-Tops.” A pair of black and white baseball boots peep out beneath Cave’s sensible brown suit. “I’d rather you didn’t report that I’m wearing these,” he requests, “I think they’d draw the line there.”

Cave’s Christianity is perhaps the most shocking thing about his recent history. His lecture The Flesh Made Word enraged a vocal minority of the audience during its 1997 Edinburgh Fringe performance, but rationalist fans could then at least excuse Cave’s God as a metaphor for the creative process. “God is a product of the creative imagination,” he wrote, “and God is that imagination taken flight.” But today the author of the introduction to the Canongate edition of St Mark’s Gospel is unequivocal. “I do accept Christ’s divinity. More and more so actually. But I don’t think a person truly believes unless they doubt as well. My faith kind of swells up and subsides. It’s going through a swelling up at the moment.”

The CD of Cave’s new album, Nocturama, features a DVD of the song Babe I’m On Fire, a vaudeville parade of various characters, all burning with passion. But to illustrate the notion of the ‘Christian apologist’ the dressing up box was closed in favour of a shot of Cave’s own expressionless face. “We tried to think what a Christian apologist would look like and we realised there was one in the room. But if one’s going to mould one’s self on someone it may as well be Christ. Better that than Mick Jagger.” Was coming out as a Christian as a shock tactic, an attention grabbing device as dramatic as calling a live album Drunk On The Pope’s Blood, which The Birthday Party did in 1982? “Well, Christianity doesn’t sell records,” counters Cave, “and it hasn’t done much for Cliff Richard.”

Even though his faith is sincere, Cave acknowledges its role in the artist’s duty to confound his audience. But lately married life is another factor that has given him a new and unexpected energy, and spared him many of the inherent pitfalls that befall other veteran rock stars. “The truth is that I’m middle aged and married and settled and there isn’t this wealth of anguish to write about. That’s definitely a problem, certainly in rock music, for people who are getting older. What do you actually write about? I write love songs I suppose. Certainly the idea of being in a stable relationship is fairly uncharted in rock music. People always write about the beginning and the end but that vast middle period is not really addressed and I find that difficult but exciting.” And how does Cave go about finding a vocabulary to address this uncharted territory? “I read WH Auden.”, he laughs, “especially in regard to his changing from being a radical writer, to writing about community, Christianity, spousal love and marriage. He managed to do it in an exciting way. There’s something very neutral and sensible about the way he writes that is really jarring in modern culture.”

Cave, at last, seems supremely comfortable with himself. And though the look-back bores will always cite The Birthday Party’s “orgies of violence” (c. Melvyn Bragg 2003) as a live highpoint, Cave’s performances can now invoke the hysterical theatrics of Las Vegas period Elvis, and the intimacy of some piano bar balladeer, without compromising any notions of artistic integrity. And Cave still enjoys performing. “I love that moment when it’s all right and you know you’re there. I constantly chase after that feeling. When it’s working there’s a voice in my head telling me ‘You are great. You are God.” I love looking into the crowd and seeing people smiling. It’s a great feeling, the feeling that you are finally where you always wanted to be. I only get that on stage and it is taken away from me as soon as I watch a film of what I’ve done, or see it on TV. Or on The South Bank Show.

Cave’s appears profoundly uninterested in watching his South Bank moment; “I don’t put myself through that sort of thing. There’s some people who do a show and go back to the hotel and listen to the show back and get sent magazine covers, and frame them and send them to their mothers, and read their own press, and make scrapbooks, and put album covers on the wall, but I’m not that sort of person,” he explains defiantly, before adding, “What’s it like anyway? Is it good?”

A DVD by Nick Cave & The Bad Seeds, God Is In The House, is available tomorrow on Mute records.