Natalie Portman’s Oscar-winning performance as a troubled ballerina in Black Swan may have appealed to critics, but her lesbian love scene earned the film more complaints than any other in the UK last year.

The British Board of Film Classification’s annual report was released today, the Independent reports.

An oral sex scene between Natalie Portman and co-star Mila Kunis was the “standout” problem.

The film had an age rating of 15, the BBFC describing the scene as “visually discreet”.

David Cooke, director of the BBFC, told the Independent: “It is a fairly strong scene, but it’s not anything like above the line. We felt Black Swan was in the boundary of a sex scene for a 15 rated film.”

40 people complained about the film with the biggest issue the lesbian love scene.

The BBFC pointed out that the number was “proportionately very small” when considering 2.7 million people had gone to see the film at the cinema.

The report adds that some complainants “argued that portrayals of homosexual activity should either be restricted to the 18 category or not shown at all”.

Mr Cooke added: “We have a clear policy in the guidelines that we don’t differentiate or discriminate whether it’s a straight or gay or lesbian scene.”

He suggested some complaints may have come from people who had expected to see a film about Tchaikovsky’s Swan Lake but were confronted with a dark psychological thriller with a homosexual element.