Spooks star David Oyelowo has said diversity on UK screens is still an issue and is getting worse.
Oyelowo played MI5 officer Danny Hunter in Spooks from 2002 to 2004, and has had supporting roles in films such as Lincoln and Rise Of The Planet Of The Apes.
Talking to the Radio Times, he said: "It's time for a change, but the question is - what needs to change in order for the frustrating regression of diversity on British television to cease?"
The actor is a patron of the TriForce Creative Network, which supports and empowers people from diverse backgrounds.
The 39-year-old described how he had tried to pitch a period drama set in 1800s London to UK broadcasters following his stint in Spooks.
The reaction to his idea was lukewarm, and was "rejected repeatedly", because "of the notion that a British audience might be confused by watching a period drama featuring black characters who historically walked the vibrant streets of London in the late 19th century".
He praised Oprah Winfrey, whom he worked with on the film Selma, calling her "discerning and powerful".
His next project, titled The Queen Of Katwe, is set in Uganda and tells the story of a chess prodigy from the slums.
"There are fantastic British film producers who are white and who feel passionate about the issue of diversity," he said.
"But the point remains that no one is going to be as passionate about telling your stories and your history as you are."