London: Sir Ian Blair on Tuesday faced new claims over his treatment of one of his most senior officers.
Friends of Tarique Ghaffur said the Metropolitan police commissioner had tried to stop him attending the Beijing Olympics in his role as the lead planner for security at the London Games in 2012.
The allegation is the latest round in the increasingly open warfare between the two men.
Ghaffur, the Met's assistant commissioner, has now decided to launch full-scale legal action against Sir Ian, claiming that he is the victim of racial discrimination.
Sources close to him and his legal team are to make further claims of misconduct against the commissioner.
Ghaffur will also submit a formal witness statement to an inquiry headed by Sir Ronnie Flanagan, the chief inspector of constabulary, who is investigating how Sir Ian's skiing companion Andy Miller secured a series of lucrative police contracts.
Ghaffur, 53, the third most senior officer in the Met, will put forward claims concerning the Commissioner's relationship with another businessman who won a consultancy contract to advise the Met on security at the London Olympics. Another potentially damning claim involves Sir Ian's role in the cash-for-honours investigation in 2006.
The Met announced that the commissioner stood aside because of his "close working relationship" with prime minister Tony Blair, but Ghaffur claims he has documents which contradict this.
The appearance of such paperwork would be highly damaging to Sir Ian, who was clear that he was not involved in the investigation, which was carried out by Deputy Assistant Commissioner John Yates. If the documents were to appear, this might raise serious questions over the commissioner's future.
Sir Ian has robustly denied he committed any impropriety in the awarding of contracts to Miller and said he informed the Met about their relationship before the contracts were awarded. No other claims of corruption have been made against him.
Friends of Ghaffur said the relationship between himself and his boss had reached a new low in the run-up to the Olympics.
"Blair did not want Tarique Ghaffur going to Beijing," a source said.
"Anyone running security at the London Olympics would have been required to go to Beijing. If he didn't go he would not be viable to be in charge of the next Olympics."
After negotiations, the Met agreed to let Ghaffur travel to the Chinese capital for the Games.
"He is not there to watch sport, he is there in order to observe and learn," the source said. "He is there now and will prepare a report when he returns."