A biopic of one of the most famous American gays of the 20th century has won two Oscars.

Sean Penn won Best Actor for his portrayal of Harvey Milk, a San Francisco politician.

He beat Richard Jenkins, (The Visitor), Frank Langella (Frost/Nixon), Brad Pitt (The Curious Case of Benjamin Button) and Mickey Rourke (The Wrestler).

Dustin Lance Black won the Oscar for Best Original Screenplay for Milk.

Mr Penn won an Oscar in 2004 for Mystic River and has been nominated three times.

Accepting his award at the 81st Academy Awards in Los Angeles he referenced the ban on gay marriage that passed in California in November.

The Oscars ceremony was targeted by homophobic Christian groups. Some held up placards claiming actor Heath Ledger, who died last year, is in Hell. Mr Ledger was named Best Supporting Actor for his performance in The Dark Knight.

“I think that it is a good time for those who voted for the ban against gay marriage to sit and reflect and anticipate their great shame and the shame in their grandchildren’s eyes if they continue that way of support,” he said.

British feelgood movie Slumdog Millionaire was named Best Picture and also won Best Director, Best Cinematography and a range of other awards. Kate Winslet won Best Actress for her role in The Reader.

Click here to read the full list of winners.

Milk, 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.

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.