A Conservative front-bencher has caused outrage after claiming that being called a "black bastard" is part-and-parcel of life for ethnic minorities in the Armed Forces.

Patrick Mercer, the Tories' Shadow Homeland Security Minister and a former colonel in the Army, also provoked controversy by saying that when he served with the Worcestershire and Sherwood Foresters before becoming an MP, he knew "a lot" of ethnic minority servicemen in the Army who used perceived discrimination as an excuse for poor performance.

Mr Mercer, who came into politics after a long Army career, was speaking to Times Online about the formation of a new anti-racism trade union being set up by servicemen from former colonial countries, which he described as "complete and utter rot".

The MP for Newark's comments are likely to embarrass David Cameron, the Conservative leader, who is desperate to make his party more open and inclusive and move it towards the political centreground.

Responding to the comments, the Tories said the remarks were a private matter as Mr Mercer was expressing a view based on his experiences in the Armed Forces, which had no relation to his frontbench portfolio.

However, they were condemned by the Runnymede Trust, an the ethnic minority pressure group, as "entirely inappropriate" and "completely unhelpful", with the organisation's director saying they were particularly disappointed that they came from a senior MP.

Mr Mercer said that suffering racial abuse - as well as abuse about facial features, hair-colour and weight - was common in the Army, and to be expected.

"I had the good fortune to command a battalion that was racially very mixed. Towards the end, I had five company sergeant majors who were all black. They were without exception UK-born, Nottingham-born men who were English - as English as you and me. They prospered inside my regiment, but if you'd said to them: 'Have you ever been called a nigger,' they would have said: 'Yes.' But equally, a chap with red hair, for example, would also get a hard time - a far harder time than a black man, in fact," he said.

"But that's the way it is in the Army. If someone is slow on the assault course, you'd get people shouting: 'Come on you fat bastard, come on you ginger bastard, come on you black bastard.'"

Mr Mercer added that he knew soldiers from ethnic minority backgrounds who used racism as an excuse for poor performance.

"I came across a lot of ethnic minority soldiers who were idle and useless, but who used racism as cover for their misdemeanours," he said.

"I remember one guy from St Anne's (Nottingham) who was constantly absent and who had a lot of girlfriends. When he came back one day I asked him why, and he would say: 'I was racially abused.' And we'd say: 'No you weren't, you were off with your girlfriends again.'"

Condemning the announcement of the formation of a new trade union proposed by Marlon Clancy, a serving soldier who was recruited from the Commonwealth in 1999 and complained of several incidents where he was racially abused, the MP for Newark said: "Absolute nonsense. Complete and utter rot."

He added: "In my experience, when you put on the uniform then all differences disappear. If you are a good soldier, you will do well. If you are a bad soldier, you will leave prematurely. There is a degree of colour-blindness among the vast majority of soldiers.

"I never came across a piece of nastiness inside the battalion that was based exclusively on racism."

Michelynn Lafleche, chairwoman of the Runnymede Trust, a charity which provides information and advice on racial equality issues, said that Mr Mercer's comments were "shocking".

"That is an entirely inappropriate response," she said.

"This is entirely the sort of thing that we have laws in place to deal with. Racial discrimination and racial harassment are against the law no matter who you are, and that means the Armed Forces as well.

"Other organisations have taken racism very seriously such as the police, as well as the Army and the Navy, in fact. Mr Mercer's reaction is entirely inappropriate, completely unhelpful, and really quite shocking.

"They are certainly inappropriate for an MP who is meant to be representing a constituency in which, I am sure, ethnic minority residents live."

The Conservative Party, in which Mr Mercer serves as a frontbench spokesman with responsibility for homeland security and anti-terrorism issues, said that his comments were a personal matter and refused to discuss them.

"These are the personal views of a highly decorated former commanding officer talking about his real life experiences in the British Army," a party spokesman said.

The controversy came after Mr Clancy, who is from Belize, said he was setting up his trade union because the 6,000 serving Commonwealth troops in the UK were being treated as "third class soldiers".

The union will not have the right to strike under Armed Forces rules, but will be able to confidentially advise ethnic minority servicemen and women in the event of discrimination or other problems, he said.

"Commonwealth soldiers are third class soldiers. First you have British-born white soldiers, then you have the British-born black soldier, then, last, you have the black Commonwealth soldier," he told the BBC.

"I am hoping this will open up a doorway for the Army to let these people know of their rights and give them what they are entitled to, and the justice they are entitled to as well."

Mr Clancy said that he had decided to launch the union after his complaints - including an attack by fellow soldiers dressed in Ku Klux Klan outfits - were ignored by the Army chain of command.

"As a serving soldier I’ve gone through the chain of command time and time again within the seven-and-a-half years I’ve been in the Army and time and time again the chain of command has failed me," he said.

In response to his announcement, the Ministry of Defence claimed there was "absolutely no evidence" of systematic racism within the British Army, and said its own procedures were in place to combat the problem when it arose.

"There is absolutely no evidence to support allegations of endemic racism in the Army – last year there were 26 complaints," a spokesman said.

"We investigate all substantive allegations of racism and would encourage anyone who has experience inappropriate behaviour to come forward.

"The Army goes to great lengths to ensure that all soldiers, irrespective of their race or ethnic origin have given the opportunity to fulfil their full potential.

"We are very conscious of the additional challenges faced by Commonwealth soldiers and their families.

"This is why we have put in place special provisions including leave arrangements that allow Commonwealth soldiers to return to their home countries."

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