Darren Grimes under police investigation after David Starkey interview

Darren Grimes is being investigated by police on suspicion of stirring up racial hatred over an interview with the historian David Starkey that he published, it has emerged.

Mr Grimes, a conservative commentator, has been asked to attend a police station to be interviewed under caution after publishing a podcast in which Dr Starkey said slavery was not genocide because there are "so many damn blacks".

It has been warned that the investigation, by the Metropolitan Police, will have a "chilling effect" on free speech, while Mr Grimes has described it as an "abuse of taxpayers money".

Mr Grimes is accused of a public order offence of stirring up racial hatred by publishing the interview on his podcast on July 2, The Telegraph can reveal. He has since apologised, while Dr Starkey's career lies in ruins, with the historian set to lose all his academic titles and book deals.

Mr Grimes said in a statement: "At a time when many in our country are facing uncertainty and financial hardship, I cannot imagine a more contemptible way for the Metropolitan Police to abuse taxpayers' money and the trust of citizens then by investigating this vexatious claim."

He said the threat of arrest has "serious repercussions for freedom of expression". His solicitor, Luke Gittos, of Murrays Partnership, said it was an "unprecedented use of Public Order legislation".

Mr Grimes is being supported by the Free Speech Union (FSU), which has described the accusation against him as "absurd".

The interview provoked furious backlash when it was published on the YouTube channel Reasoned UK in the summer.

In the days after making his comments during a discussion of the Black Lives Matter Movement, Dr Starkey lost his academic positions at Fitzwilliam College, Cambridge and Canterbury Christ Church University. HarperCollins, which had been expected to publish two more of his history books, said it was cancelling their release.

Toby Young, the General Secretary of the FSU, said: "The only hatred Dr Starkey stirred up was against himself. Mr Grimes himself publicly apologised for having broadcast Dr Starkey's remarks, saying that he 'should have robustly questioned Dr Starkey about his comments'.

"Plainly, Mr Grimes would never have made this announcement if he had intended to stir up racial hatred in the course of a broadcast only days earlier."

Mr Young questioned whether journalists would now be arrested over comments made by their interviewees and asked if similar action was being taken against a Sky News presenter who was interviewing the rapper Wiley when he made offensive comments about Jewish people.

He added: "In a free and democratic society, it is paramount that journalists and broadcasters are permitted to interview a wide range of people, including those likely to make controversial remarks.

"Threatening them with arrest if their interviewees say something offensive will have a chilling effect on free speech, which is the lifeblood of democracy."

The public order offence which Mr Grimes is accused of carries a maximum penalty of seven years in prison.

Scotland Yard said: "On July 4, the Metropolitan Police Service was passed an allegation from Durham Police of a public order offence relating to a social media video posted online on June 30. The matter is currently being investigated. No arrests.”

The Telegraph understands that Dr Starkey has not been contacted by police.