He is the poster boy of the BNP, an articulate former teacher whose blue eyes and easy charm helped win the far-right party 11 council seats in Barking, east London. But now Richard Barnbrook, London leader of the BNP, has been forced to deny that an erotic movie he produced and directed as a student was a gay porn film.

HMS Discovery: A Love Story contains scenes of flagellation, men undressing and frolicking in a river and a naked man apparently performing a sex act on another. While this may be hard for supporters of a party opposed to the "promotion" of homosexuality to swallow, Mr Barnbrook's transgressions get worse: the 58-minute film, made in 1989, is described as "Marxist" by one film website.

"It was an art film, end of story. It was not a bloody porn film," said Mr Barnbrook, now leader of the opposition on Barking council. "The only nudity in it is a couple of guys running in a river. It is not about homosexuality. It is about sexuality. Anything to do with my past politics or my past work, I am not interested in commenting on."

The existence of the film was first revealed in the Guardian before last year's general election, when Mr Barnbrook stood as a candidate in Barking. According to one cinema listing, Mr Barnbrook also starred in and co-wrote the film.

But yesterday he denied penning erotic poetry set to the footage, which includes the lines: "It bares you like a foreskin's folds" and "Open-mouthed, I shall dream of altar boys."

Mr Barnbrook was a painter, conceptual artist and art teacher before turning to rightwing politics. Searchlight, the anti-fascist organisation, has suggested he was also a Labour party member at one stage. Fellow extremists appear to take a dim view of Mr Barnbrook's colourful past. On one rightwing website, a poll has been created next to a picture of the BNP man asking: "Is this a poofter or what?"