Cumberbatch played pioneering World War 2 codebreaker Alan Turing in The Imitation Game. Turing was prosecuted for being gay, but he was given a posthumous pardon in 2013.
The actor has signed an open letter calling for some 49,000 other men similarly convicted under the old law to have the same treatment as Turing. The petition has already been signed by almost 90,000 supporters.
The Duke and Duchess of Cambridge yesterday rejected Cumberbatch’s plea to support the campaign, with a spokesperson saying that it is a matter for government, so they could make no comment.
Cumberbatch has teamed up with other public figures such as Stephen Fry for the campaign. (Read more about the homosexual pardon campaign HERE)