The BBC is facing a growing backlash over its decision to rebuke presenter Naga Munchetty following remarks she made about US President Donald Trump.
Sir Lenny Henry, comedian Gina Yashere and actor Adrian Lester are among a host of black stars to write to the broadcaster branding their stance as "deeply flawed" and "illegal".
Munchetty was found to have been in breach of BBC editorial guidelines when she said on air that Mr Trump’s call for a group of female Democrats to "go back" to their own countries was "embedded in racism".
An open letter to the BBC, signed by Sir Lenny, Yashere, Lester and dozens of others, including Sky News presenter Gillian Joseph, said: "To require journalists of all ethnicities and races to endorse racism as a legitimate ‘opinion’ is an abrogation of responsibility of the most serious nature."
It added that the ruling was "both a misunderstanding of the BBC’s editorial guidelines, and a form of racially discriminatory treatment towards BAME people who work on programming".
The letter, published in the Guardian, ended by saying it believed that "in addition to being deeply flawed, illegal and contrary to the spirit and purpose of public broadcasting, the BBC’s current position will have a profound effect on future diversity within the BBC".
There has also been political criticism of the decision, with Chancellor Sajid Javid describing it as "ridiculous".
He wrote in a tweet: "It’s perfectly understandable why she said what she did."
Meanwhile, Labour MP Clive Lewis has started a parliamentary petition condemning the "perverse" position.
In a bid to stem the controversy, BBC director general Lord Tony Hall and other executives sent a letter to corporation staff on Friday assuring them that "racism is racism" and that "diversity matters hugely".
It stated: "You will have heard a lot of comment over the past few days about the BBC and the reporting of racism.
"The BBC is not impartial on racism. Racism is not an opinion and it is not a matter for debate. Racism is racism.
"Naga Munchetty — one of our stars — was completely within her rights to speak about the tweets of Donald Trump which have been widely condemned as racist."
The BBC ruled that Munchetty crossed the line when she commented on controversial statements made by Mr Trump directed at rival politicians Ilhan Omar, Alexandria Ocasio-Cortez, Rashida Tlaib and Ayanna Pressley.
She told her Breakfast co-presenter Dan Walker: "Every time I have been told, as a woman of colour, to go back to where I came from, that was embedded in racism.
"I’m not accusing anyone of anything here, but you know what certain phrases mean."
Questioned further, she said she was "absolutely furious a man in that position thinks it’s OK to skirt the lines by using language like that".
The BBC initially commented saying: "Overall her comments went beyond what the guidelines allow for."
On Friday, Ofcom released a statement saying they had released complaints about BBC Breakfast.
"We have recently received complaints relating to this programme and we are assessing the content against our own broadcasting rules," the statement read.