Sean Penn last night won the Screen Actors Guild award for his portrayal of the gay politician Harvey Milk in the film Milk.

The film directed by Gus Van Sant catalogues the life and times of Harvey Milk, the first openly gay man to be elected to public office in the United States

Accepting the award Sean Penn said: “As actors, we don’t play gay, straight. We don’t play any of these kinds of people. We play human beings, and this movie is something that all of us involved are so proud of.”

He added: “This is a story about equal rights for all human beings.”

Known during his lifetime as “The Mayor of Castro Street,” he is a political icon among gay activists for his ability to build the LGBT community into a grassroots political force.

Milk was elected to the San Francisco Board of Supervisors in 1977.

In his 11 months in office he sponsored a gay rights bill and helped to defeat a proposition that would have seen openly gay and lesbian teachers sacked.

He was gunned down at City Hall by Dan White, a disgruntled former Supervisor, on November 27th 1978.

Milk was recently honoured with a bust on permanent display in San Francisco City Hall, a rare accolade for someone who never held the position of Mayor.

The film is nominated for eight Oscars.

The late Heath Ledger, who played a gay cowboy in Brokeback Mountain won a posthumous award for the role of the Joker in Batman: The Dark Knight.