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Sir Lenny Henry will deliver a letter to 10 Downing Street in an attempt to increase the number of women, BAME and disabled people working in film and TV.
The letter calls for tax relief to help boost diversity behind the camera. Actor Adrian Lester will hand deliver the letter with Sir Lenny at 14:00 GMT.
Other signatories include Chiwetel Ejiofor, Thandie Newton, David Oyelowo, Dame Emma Thompson and Jodie Whittaker.
"All we're asking for is a seat at the table," Sir Lenny told BBC News.
"We're still in a situation where we might not get a job because of the way we look, or somebody perceives that our education isn't up to scratch, or we might not even get in the door for an interview.
"To me, if there was a structure that said, if you choose to do this you will get a tax break - people understand that - and these things benefit the industry and bring in more money.
"All we're asking for is a seat at the table, but at the moment, we're still behind the door like Dickensian children and that needs to stop."
'Shocking' figures
The letter says Britain's "talented women, BAME and disabled creatives... enrich the creativity of the UK and add to our cultural heritage, but unfortunately they continue to be the exception rather than the rule".
It adds: "We believe the implementation of Representation Tax Relief is necessary because diversity in important sections of the UK film and television industry is in crisis."
The letter also describes the statistics for the representation of women and BAME and disabled people as "shocking", and cites a report by Directors UK, which found that only 2% of UK television is made by directors from BAME backgrounds.
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