Not so luvvie: anger at Cannes over Diana film bankrolled by al-Fayed

British actor Keith Allen faced angry questions at the Cannes Film Festival yesterday over a controversial documentary about the death of Diana, Princess of Wales, after it emerged Mohamed al-Fayed had bankrolled the film with £2.5 million.

Allen, the British television actor and comedian and father of singer Lily Allen, insisted that Unlawful Killing was not a "sensationalist film", but was grilled by journalists over why he had failed to disclose Fayed's involvement.

The film is not among the official selections at Cannes this year, but was screened there yesterday for the first time. It appeared to have achieved the goal of stirring media interest - but Allen was repeatedly challenged over accepting support from Fayed, whose son Dodi died in the 1997 car crash that killed Diana and who embraced conspiracy theories surrounding their deaths.

The actor said yesterday that his production team had sought backing from the BBC and other British television producers for the film but claimed they were told it was "never going to happen". He added: "So I asked Mohammed al-Fayed if he would fund it, which he agreed to do."

The film examines the inquest of Princess Diana and claims of an alleged conspiracy in the way it was reported. Allen called it "an inquest of the inquest". A journalist working with Allen, Richard Wiseman, went "undercover" among the press corps covering the inquest.

Allen told a press conference: "I didn't want to make a sensationalist film. I don't believe it is a sensationalist film. I think it is a very forensic analysis of a process, a British legal process, and I think it reveals things that, I'm sorry, don't add up."

A spokesman for Mr Fayed confirmed that the former Harrods boss had provided around 2.5m to fund the documentary, which features contributions ranging from the late Tony Curtis, to broadcaster and journalist Piers Morgan, George Galloway, American shock jock Howard Stern, and Mr Fayed himself.

But it is unlikely ever to be seen by general UK audiences, as lawyers have concluded the Cannes version would require 87 cuts before being screened here. Allen said there was a chance it could be screened at the London Film Festival.

Asked by an American journalist why he didn't disclose Al Fayed's financial involvement earlier, Allen said: "I don't understand. At which point in the film would I have said to the viewers: ‘By the way, this was financed by Mr Fayed?'"

But Martyn Gregory, author of a book on Diana's last days, then accused Mr Allen of "simple regurgitation of everything Mohamed al-Fayed has been saying since the year 2000… nothing in the film is new."

When Gregory demanded to know why Fayed himself was not at the press conference, Allen said: "How would I know? I'm not his keeper."

He added: "Screening this film in Cannes for the world's media will be both exhilarating and terrifying for me. As far back as 2004, I had been intrigued by Mohamed al-Fayed's unrelenting determination to seek answers to the questions… This film is, in short, the inquest of the inquest."

The comic and actor added that the film made reference to Nazi connections of the Duke of Edinburgh's family "as background information" and defended the brief use of a photograph which showed Diana in the car after the crash which he said was not "as sensational or revealing as people make it out to be".