Gun exposé voted top factual film

Moore is known for his satirical books and films

Bowling for Columbine, the latest film by United States satirist Michael Moore, has been named the best documentary of all time by leading factual film-makers from around the world.

The International Documentary Association (IDA) chose Moore's controversial exploration of US gun culture, boosting the film's prospects for Oscars success in March.

Moore also took third place on the list with his 1989 film Roger and Me, in which he took on car makers General Motors over factory closures that led to large scale job losses.

In second place was 1988's The Thin Blue Line, about wrongful convictions arising from the 1976 murder of a policeman in Dallas, Texas.

Actor Charlton Heston is featured in the film

The IDA's executive director Sandra Ruch said: "All these films provide an intimate, behind-the-scenes look at the human condition.

"They make you think about things you might not have ever considered before."

The IDA, formed in 1982, acts as a forum for documentary film-makers and has around 2,700 members in 50 countries.

Strict rules

Moore's film focuses on Columbine High School in Colorado, the site of 1999's tragic high school massacre when two teenagers killed 12 students and a teacher.

In it, Moore talks to people around the US including actor Charlton Heston, a prominent pro-gun lobbyist.

His film has won a string of awards at film festivals around the world, including a special jury prize at Cannes.

Bowling For Columbine has done well at the box office

It is now considered among the films likely to triumph in the documentary category at the upcoming Academy Awards.

The National Board of Review in the US also recently named the film as the year's best documentary. The board is seen as a pointer towards possible Oscars winners.

Also on Thursday, the Academy of Motion Picture Arts and Sciences - the Oscars awarding body - announced it had tightened its eligibility rules for documentaries wanting to be put forward for nomination.

In addition to the requirement that a factual film must have been shown in Los Angeles or Manhattan for at least seven days, documentaries must now have been shown in cinemas in four other cities.

If this requirement cannot be met, then a film - if nominated - must be withheld from TV and internet transmission for the nine months after the day nominations are announced.

Cinema hit

Bowling For Columbine has done well at the US box office against competition from fictional Hollywood blockbusters.

So far, it has taken $12.9m (£8.1m), which is a big sum for a documentary. In the UK, it also entered the top 10.

Documentaries are usually restricted to film festivals and cable television channels because the material is often considered hard work for cinema-goers looking for escapism.

Oscar nominations are announced on 11 February and the awards will be handed out in a gala ceremony in Los Angeles on 23 March.