The outsider status of graffiti artist Banksy took a further blow today with the announcement that he has been longlisted for an Oscar for his documentary film, Exit Through the Gift Shop.

The anonymous spray can provocateur may have begun his career tagging around his native Bristol, but he is now in danger of being embraced as firmly by the movie mainstream as he has been by the art world. Earlier this month the film, which received enthusiastic critical reviews on both sides of the Atlantic, was awarded a prestigious Grierson documentary award.

The film, which premiered at the Sundance film festival last year, was described by the artist as "the story of how one man set out to film the unfilmable – and failed". It tells the story of a Los Angeles T-shirt printer called Thierry Guetta who becomes obsessed with street art and attempts to make a film about it, only to have Banksy, on seeing the catastrophic results, turn the camera on Guetta.

The Lost Angeles Times described it as "subversive, provocative and unexpected … a hall of mirrors as unsettling as anything Lewis Carroll's Alice ever experienced".

The documentary longlist of 15 includes films by a number of other Britons, including Enemies of the People, a personal film about the killing fields of Cambodia directed by Rob Lemkin and Thet Sambath, and Lucy Walker's Waste Land, about an artist who works with Brazilian slum-dwellers to create works of art made from rubbish.

The list will be whittled down to five films in January, with the winner revealed at the Oscars ceremony on February 27. Recent winners of the best documentary award have included Al Gore's environmental film An Inconvenient Truth and Michael Moore's Bowling For Columbine.