First Night: Dirty Pretty Things/The Enemy, HMP Pentonville, London

The jailhouse rocks as Carl Barat and friends perform behind bars

Dressed in skinny jeans, a retro T-shirt and a grandad cardigan, the singer Carl Barat cut an unlikely figure inside the walls of Pentonville. As sun glinted off the coils of razorwire, a small crew of press and musicians were escorted through a security "airlock" into the heart of the London prison for a concert, the like of which has seldom been seen since Johnny Cash strummed his way around US jails in the 1960s. About 180 Pentonville inmates were being treated to a concert by two of Britain's biggest indie bands: Barat's Dirty Pretty Things and The Enemy.

The venue was the spartan prison chapel which, with its religious icons and stacking chairs, gave the concert the air of a rowdy church meeting.

The gig was part of the Wasted Youth campaign to raise awareness of high suicide rates among young men. The crowd looked distinctly nonplussed as Pentonville's governor, Nick Leader, came on stage to hammer home the educational message that "being silent isn't strong". However, once he explained the statistics (67 prison suicides last year and 59 already this year), the crowd fell silent.

The Enemy were the first to play and, once they had rattled out the exuberant chorus of their hit single "Away From Here", the seated prisoners began to loosen up. The song was delivered with the youthful band's usual hyperactivity, and had one inmate forcibly demonstrating to his elderly neighbour how to headbang in time with the music.

By the time Dirty Pretty Things walked out from beneath the chapel's barred stained glass windows, the atmosphere was visibly relaxed. But the audience were still subdued, letting only their fingers and toes move to the music, and not getting out of their seats except to applaud at the end. Before going on stage, Barat said he had been terrified of making a faux pas with his captive crowd. "I'm trying to rule out the stupid things I could say, like 'thanks for coming', or 'I went on a real bender last night'." This might explain his monosyllabic exchanges with the prisoners, which rarely went beyond a few mumbled song titles and a "thanks very much".

His former Libertines bandmate, Pete Doherty, who has spent time in Pentonville himself, had apparently been keen to play but was vetoed by the Prison Service, which thought his presence would detract from the event. Wasted Youth's Dan Fulvio said the organisation was disappointedthat the renegade singer was barred, adding: "We thought it would be a perfect symbol of friendship and forgiveness between the two bands."

One convict jailed for drugs offences agreed, saying: "They should have let him come because he knows - he has the same problems as us. The only difference is he can afford the drugs."