When Penny Woolcock offered Birmingham gang members the chance to star in an unflinching film on their lives, the local crime rate slumped.

Now the director has accused the police of racism after a ban by cinema chains in the Midlands has prevented the stars of 1 Day from seeing their own film. A low-budget “hip-hop musical”, shot on the streets of Birmingham with an entirely black cast, 1 Day was one of the highlights of The Times BFI London Film Festival.

Woolcock, praised for her provocative films placing marginal communities on screen, held “street auditions” to cast amateur actors and musicians for 1 Day. Released nationwide this weekend, the £750,000 film, backed by Channel 4 and the UK Film Council, depicts a day in the life of a drug dealer and the gang warfare that ensues when a deal goes wrong. Days before its release, however, an e-mail purporting to be from a gang member warned of a planned shoot-out between three Birmingham city gangs at a cinema screening.

Inner-city gang warfare has blighted Birmingham in recent years and the film portrays the violent postcode rivalry between two “crews” — the Zampa Boys and the Old Street Crew. Concerns were raised by a West Midlands Police officer, who contacted cinemas proposing to screen the film, which has a 15 certificate.

A virtual West Midlands blackout has resulted, with cinemas in Birmingham, Dudley, Walsall and Coventry all pulling the plug. A preview screening, attended by a largely black audience in Birmingham, was interrupted by the police who switched the lights on and conducted a headcount. The officers said that they had been called over “a problem with the projector”.

Sion Simon, Arts Minister and MP for Birmingham Erdington, is believed to be furious over the police interference and has asked for an explanation.

Ms Woolcock, who spent weeks listening to first-hand accounts of gang life for research, is saddened by the row. She told The Times: “There is no serious evidence of any real threat from gangs. I am afraid there’s an element of racism to the police harassment. It is not for the police to tell people what they can and cannot watch.”

Community police and probation officers praised the production when Ms Woolcock and her team shot scenes in Handsworth. She said: “The crime rate went down because we were giving young people an avenue to channel their positive energies.”

The film does not glamorise violence, said Ms Woolcock, 59. “The people who use guns get killed, but the film does not offer any easy redemption. There is more violence in a Hollywood blockbuster than my film.”

Suzette Davenport, Assistant Chief Constable of the West Midlands, denied that the force had advised cinemas not to screen 1 Day, but admitted one officer had expressed “a personal view with the best of intentions”.

Shooting People, a body representing independent film-makers, is urging its 35,000 members to see 1 Day in support of Ms Woolcock.

The director added: “If we stamp on a small British film, instead of celebrating that achievement, all we will end up with in our cinemas is Transformers, and that really is violent.”

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