British documentary Unlawful Killing was the focus of attention for the media at the Cannes Film Festival on Friday. Its makers claim the film throws light on circumstances surrounding the death of Diana, Princess of Wales in 1997. But at a stormy media conference after its premiere, director Keith Allen was repeatedly asked to explain what new evidence he believes the film contains. Allen disagreed with suggestions he should have made it clear on screen that the film was funded by the businessman Mohamed Al Fayed, saying it would have interrupted the film's flow. Conor Nolan, Mr Al Fayed's spokesman, said the former owner of Harrods had invested £2.5m in the documentary. Mr Al Fayed's son, Dodi, was also killed in the crash as well as driver Henri Paul. The sole survivor, Trevor Rees-Jones, does not feature in the film. In its structure, Unlawful Killing is like many documentaries seen on TV. Narrated by Allen, it is a mixture of archive footage, new interviews, graphics and reconstructions of scenes from the 2007 inquest in London. Only music by Dave Stewart gives a slightly more cinematic feel. Allen said the producers initially sought funding from TV organisations in the UK, including the BBC. When the project was universally rejected, they were happy to accept finance from Mr Al Fayed. Allen insisted Mr Al Fayed had had no editorial input, although he appears in several sequences. At one point he is seen burning Harrods' former 'By Royal Appointment' signs, a short distance from his son's grave in Surrey.