Benedict Cumberbatch has apologised after referring to black actors as “coloured” during an interview on US television, saying he is “devastated” to have caused offence.

The Sherlock actor said he was “an idiot” after he used the phrase during a debate, ironically about the diversity problems that black British actors face in the UK compared to the US, which he argued has been more open to casting them.

Talking on the Tavis Smiley show on PBS, Cumberbatch said: “I think as far as coloured actors go, it gets really different in the UK, and a lot of my friends have had more opportunities here [in America] than in the UK, and that’s something that needs to change.”

Reaction was mixed after the actor – who has been nominated for an Oscar for his role in The Imitation Game – used the outdated term, with many praising the sentiment of his argument but lamenting his poor choice of words.

A spokesperson for the anti-racism charity Show Racism the Red Card, told the Independent: “Benedict Cumberbatch has highlighted a very important issue within the entertainment industry and within society. In doing so, he has also inadvertently highlighted the issue of appropriate terminology and the evolution of language.”

They added that the organisation feels the term “has the potential to cause offence due to the connotations associated with the term and its historical usage”.

In a statement Cumberbatch said: “I’m devastated to have caused offence by using this outmoded terminology. I offer my sincere apologies. I make no excuse for my being an idiot and know the damage is done.”

Cumberbatch found himself in a race controversy last year, when Stacey Cumberbatch, the city commissioner in New York, told the New York Times that she believed Cumberbatch’s fifth great-grandfather had owned her ancestors, who were held at a sugar plantation in Barbados.

The actor has spoken about his family’s past as slave owners and revealed that his mother once advised him to not use his name professionally in case of reparations claims by the descendants of slaves.

The PBS debate came at a time when British actors are enjoying high-profile success in Hollywood. Last year Chiwetel Ejiofor was nominated for an Oscar for his portrayal of Solomon Northup in 12 Years a Slave – in which Cumberbatch co-starred. This year David Oyelowo has won praise for his performance in Ava DuVernay’s film Selma.

Many black British actors have found that opportunities in the States have far exceeded those at home. Idris Elba’s career took off after he crossed the Atlantic for a role as Baltimore’s cerebral drug dealer Stringer Bell in The Wire, while Thandie Newton, Carmen Ejogo and Naomie Harris have all taken leading roles in American films and TV shows.

Last year in the UK, Lenny Henry spoke out about the lack of non-white people working in television and called for channels to reflect the country’s ethnically diverse population.

