An inquiry into the leak of findings about the death of Brazilian Jean Charles de Menezes has been demanded.
The IPCC appealed for witnesses to the Menezes shooting
The Home Secretary was asked to take action by both the Metropolitan Police Federation and the Police Federation.
The Independent Police Complaints Commission leak prompted claims that police had covered up details of the 27-year-old's shooting by officers.
Earlier, the IPCC rejected a complaint by a Metropolitan Police officer about its handling of the investigation.
Mr Menezes was shot by police at Stockwell Tube station after being mistaken for a suicide bomber a day after the failed 21 July bombings.
The leak of details from the IPCC inquiry contradicted much of what had previously been thought about his death and prompted demands by Mr Menezes' family for the resignation of Met Police chief Sir Ian Blair.
The home secretary was asked to launch an independent inquiry into the "unauthorised disclosure" of the IPCC findings.
Glen Smyth, chairman of the Met Police Federation, said it had written to Charles Clarke because it saw "no value in writing to the IPCC about the conduct of its own people".
He said: "It does not seem able to police itself - if we thought it could we would not be writing to the home secretary."
The Police Federation also wrote to the IPCC to say the leaks called into question its ability to conduct inquiries in a "professional and independent manner".
The IPCC rejected a complaint about its handling of the inquiry by Met police officer Simon Thurston.
He said the body's deputy chairman, John Wadham, had prejudiced the inquiry when he said that overcoming the Met's initial resistance to its investigation was an important victory.
The officer from Heathrow's armed unit said the comments were "unacceptable" as the role of the IPCC was "not about gaining scalps over the police".
After rejecting the complaint, the IPCC said: "People are free to criticise and disagree with us, but this is not a conduct matter and therefore no further action will be taken."