And the Oscar for the best voting system goes to ... AV

Both camps in the UK's Alternative Vote battle have sought to sprinkle celebrity stardust on their campaigns. Now Hollywood itself has come out for a Yes vote, proclaiming that AV is the ideal system to choose the film world's top honour.

The American Academy of Motion Picture Arts and Sciences (Ampas) replaced first-past-the-post with a preferential ranking system to decide the Best Picture award two years ago after it increased the number of nominees from five to 10. With 10 nominees it would have been theoretically possible for a film to win the top award with 11 per cent of the vote.

Bruce Davis, executive director of Ampas, told The Independent: "For our most important category we wanted to ensure that more than half the electorate endorsed the choice. We're very happy with the way it's working and we don't plan to change it."

The Academy's 5,777 members were asked to write the name of their first choice and list their alternate choices, in order of preference. As with AV, the worst performers are eliminated, with votes redistributed in each "round", until a nominee secures more than 50 per cent support. The results are counted by PricewaterhouseCoopers but the tallies are never revealed.

The Academy returned to the preferential system it used in the 1930s, because it "allows us to identify the film that members as a whole admire most, as distinct from one that may be supported almost entirely by a small but passionate minority".

Mr Davis said AV had increased the Oscars' voting turnout: "There was a certain trepidation from our members when we first announced it that it might prove more cumbersome. But we explained the system and PricewaterhouseCoopers told us that more members actually voted than before.

"There were lots of conspiracy theory blogs about how people could rig the voting but they proved fatuous. You want to find the picture that has the broadest support rather than the most passionate support by a minority."

In 2010, the preferential system rewarded Kathryn Bigelow's powerful war film The Hurt Locker. This year The King's Speech triumphed against The Social Network, a decision which may have influenced the film's stars, Colin Firth and Helena Bonham Carter, to endorse the Yes campaign.

Mr Davis said "AV" could be used for final voting in other categories but that the winners chosen under first-past-the post often do win decisively, receiving more than 50 per cent of the vote.

He was unaware of the UK referendum but knew that the Oscars' system was used to elect the Australian government and in municipal US elections. "It saves money because there is less need for run-off elections," he said.

The Academy sent detailed information about the revived system to members, which advised that "Except in a year that sees an extremely tight race between multiple contenders, the Best Picture is very likely to be determined entirely on the basis of voters' first or second preferences."

Voting experts pointed to the decision, in both "AV years", to award the Best Director prize, under first-past-the-post, to the same film which won the Best Picture category.

The FairVote organisation said that this showed AV was not producing "second choice", compromise Best Picture winners, but films which had widespread support. The preferential system also reduces the potential of a block vote giving a particular film an "unrepresentative" advantage.

Rob Richie, FairVote Executive Director, commented: "A movie is not going to win by being everyone's second choice ... Instant Run-off Voting [AV] will elect the movie that more voters prefer to its top competitor."