The latest gangster flick set to cause a storm is Antonia Bird's stylish Face. As well as man-of-the-moment Robert Carlyle, it also sees popster Damon Albarn rubbing shoulders with real-life victim of injustice Gerry Conlon
Antonia Bird's gangland thriller Face takes its title from the name given to professional criminals. Yet among the professional actors playing these career hoods (Robert Carlyle and Phil Daniels to mention but two), there are some different kinds of "faces" altogether. Blur's Damon Albarn crops up as the callow driver of a getaway car, while Gerry Conlon - of that other famous group, the Guildford Four, puts in a brief cameo as a drug dealer called Vince.

While Hollywood directors often have to name "names" to get a project off the ground, director Antonia Bird has a reputation for making the kind of social dramas (such as Safe and Priest) that don't ride on the lure of a money-grossing star. But if the casting of Carlyle has proved felicitous (the popular success of The Full Monty looks like making him into exactly the kind of star who can "open" a British film), then handing out roles to Albarn and Conlon shows that Bird is not one to pass up the opportunity for just such crowd-pulling casting.

Albarn is the latest in a long line of pop singers to pay their dues as fledgling film stars in modest, credibility-enhancing cameo roles. Nick Cave, Debbie Harry and Lyle Lovett have all traded their established pop charisma for cautious "cross-over" screen credits, while Tom Waits is practically the patron saint of cameos, popping up in films from Ironweed to Dracula as a bar-fly or mad man, or both.

By appearing in Face, Albarn illustrates the age-old yen of the popster to prove that his talent and versatility stretch beyond teeny-bop. However small a role, his appearance in a sexily-filmed gangster movie supplements a "street" screen persona that has so far been limited to pop videos.

Like Phil "Buster" Collins and the Kemp brothers (aka the Kray Twins), Albarn doesn't exactly have a reputation for being dangerous. But there's a legacy of rock-star delinquency dating back to Elvis that means pop singers are often cast in roles which are, at least, morally ambiguous. It's an often-explicit attempt to represent a "counter-culture" on screen - the bit-part personification of a marketable, glamorised lawlessness that's as bent and as common as a fake tenner.

Of course, if a pop star's pose of delinquency isn't good enough, you can always get the real thing. Writing about Face recently, scriptwriter Ronan Bennett said that the casting of Gerry Conlon was intended to give the ex-prisoner "some focus". While Bennett's concern for Conlon is undoubtedly genuine, he also admitted that "the line `I've had experience of the Old Bill' should have some extra meaning in his mouth."

The difference is that this extra meaning comes from Conlon's cashing in, not on an established pop persona, but on his own history and identity. Certainly the film will benefit from this ironic slice of actualite, but what does Conlon gain? If he's lucky, it's a straight trade-off for a piece of the film- star's fame and fortune. If he's not, he may end up going the way of "Mad" Frankie Fraser, whose recent role in another London gangster thriller, Hard Men, simply confirmed his status as living theme park, a victim of his own willingness to franchise his life for cash.