Another of Boris Johnson's appointees is embroiled in scandal after accusing British athletes of being “tainted” with blood over China's human rights records.

The Mayor of London, already under pressure over the departure of several senior appointments, was forced to distance himself last night from Brian Coleman, a senior Tory member of the London Assembly.

Mr Coleman, who was appointed by the mayor as chairman of the London Fire and Emergency Planning Authority, accused Britain's Olympians of “leaving their consciences at passport control” when they attended the Beijing Games.

The mayor has denounced the remarks as offensive and preposterous, but refused to comment on whether any action would be taken against his colleague.

The British Olympic Association reacted with outrage to the comments, which came just days after the athletes returned back to Britain, showered in medals.

Lord Moynihan, the BOA chairman, said: “I have never heard such rubbish. Our soldiers and athletes deserve more respect and any further response to Mr Coleman's sentiments would be a waste of words.”

Mr Coleman faced criticism last month when it emerged that he had spent £8,000 of taxpayer funds on taxis in one year, more than every other assembly member combined.

His remarks increase the pressure on Mr Johnson and will raise further questions about the appropriateness of his advisers.

Ray Lewis, the deputy mayor for youth, who was at the centre of Mr Johnson's attempt to fight knife crime, resigned after he was forced to deny allegations of inappropriate conduct and financial irregularities in his past. James McGrath, the mayor's senior political strategist, left over a race row. Only last week, Mr Johnson's administration suffered a severe blow when Tim Parker, the most senior member of his team, resigned abruptly only weeks after taking up his post.

Mr Parker - a City executive with a slash-and-burn reputation - resigned as first deputy mayor and chief of staff. While he insisted that the parting was amicable, The Times has been told of clashes between the millionaire businessman and other senior advisers at City Hall.

In the latest controversy Mr Coleman, the Conservative assembly member for Barnet & Camden, wrote in his weekly column for a local newspaper: “While Britain's athletes may have won more medals than usual, they must remember that they are tainted with the blood of Tibetans, Falun Gong practitioners and Roman Catholic priests.

“If you are looking for young heroes and role models, forget the highly paid athletes who leave their consciences at passport control and consider the sacrifice being made by our soldiers in Afghanistan and Iraq.”

He added that Mr Johnson had been forced to go to Beijing to collect the Olympic flag: “I would have told the International Olympic Committee to put it in the post.”

A spokesman for Mr Johnson said that Mr Coleman was entitled to his views on the Olympics as it was a “matter of taste and political opinion”.

However, he said: “It is preposterous to suggest that Boris Johnson was forced to go to Beijing. He did so with great enthusiam and is extremely grateful to his hosts.”

He said that Mr Johnson “rejects absolutely” the suggestion that British athletes were tainted. “It is offensive to suggest so when these fine young men and women are not only doing Britain proud but are helping to open China to the world and the world to China.”

Valerie Shawcross, a Labour assembly member, said that Mr Johnson's support for the athletes had been “totally undermined” by Mr Coleman.

“He has gone out of his way to personally attack, insult and disparage the remarkable achievements of the British team,” she said. “Mr Coleman's gross insult does nothing but undermine and embarrass the city.”

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