Audience members last night (11 July) took over a London screening of the feature length documentary Injustice after legal threats prompted staff at the venue, the Conway Hall, to try and abort the screening.

London-based documentary production company Migrant Media had hired London's Conway Hall and installed a video projector and sound equipment to screen the film, which depicts the effects of deaths in police custody on families, and implicates several police officers.

"[Conway Hall] received legal threats and they were told by solicitors representing a number of police officers that they could be sued for libel if the screening went ahead," said Ken Fero, producer and co-director of the film. "They subsequently tried to stop the screening. Staff wanted to switch on all the lights, and some of the audience weren't having it."

According to Fero, there were around 200 people at the screening.

A previous screening at London's Metro Cinema last Friday was pulled after the venue received a solicitor's letter at 1811, just 19 minutes before the scheduled 1830 show time.

Despite this, the film has already screened publicly during April's Human Rights Watch International Film Festival in London. More screenings of the film, which was seven years in production and cost £250,000, are planned in London and Manchester.

"It does raise a discussion of film-makers rights," said Ken Fero.

Tariq Mehmood, co-director of the film, said: "The police federation are effectively trying to ban this film. As journalists we condemn this attack on our work to expose fundamental human rights abuses in our society."

A spokesperson for the Police Federation said: "The solicitors acting on behalf of the officers have tried to secure a private viewing, and as far as I'm aware that hasn't happened."

Staff at Conway Hall declined to comment.