The Metropolitan Police has a policy of “cover-up and containment” that punishes officers who complain of racism and homophobia within its ranks, a gay mixed race ex-police officer has said.

Kevin Maxwell, 35, a former counter-terrorism officer, was sacked after raising concerns about racist and homophobic behaviour by some of his colleagues.

An employment tribunal in 2012 found the Met responsible for 44 counts of harassment and discrimination against Mr Maxwell. Most of the findings were upheld on appeal.

One officer talked of gay men “taking it up the arse”, and the tribunal found that another officer described a man in a photograph as being “as gay as a gay in a gay tea shop.”

The tribunal also found that a Met employee had leaked details about Mr Maxwell to The Sun, which he said endangered his safety.

Mr Maxwell yesterday delivered his documents about the case to the House of Commons. He claims Scotland Yard tried to destroy him and that his experiences showed the force had failed to learn lessons since the murder of Stephen Lawrence in 1993.

The Macpherson Report of 1998 concluded that the Met had been “institutionally racist” in the way it had investigated the death of the 18-year-old.

“I should have been what they have been banging on about for the last 20 years,” Mr Maxwell told The Independent. “I am meant to be the future. I ticked all of those diversity boxes. Where did they go wrong? Is there still institutional racism and homophobia? Yes, without a doubt.”

The 35-year-old joined Greater Manchester Police aged 23, and in October 2008 joined the Met, winning a posting to its elite counter-terrorism command, SO15, stationed at Heathrow Airport.

Mr Maxwell first complained in July 2009 about racist and homophobic abuse.

He believes that the force tried to discredit and intimidate him into silence, which resulted in him suffering from chronic depression.