A senior Scotland Yard officer has consulted libel lawyers over a Metropolitan Police statement on the shooting of Jean Charles de Menezes.
Mr Paddick says the Met statement amounted to accusing him of lying
Brian Paddick said he had claimed a close aide of Met chief Sir Ian Blair thought police had shot an innocent man, six hours after the Tube killing.
The Met responded that the claim was "simply not true"; Mr Paddick said that amounted to accusing him of lying.
Sir Ian maintains he did not know the victim was innocent until the next day.
Mr Menezes, a Brazilian electrician, was shot dead at Stockwell station after being mistaken for a terrorist suspect, the day after the 21 July alleged bombing attempts.
It was reported on Thursday that a senior officer had told Independent Police Complaints Commission investigators that a member of Sir Ian's private office team believed the wrong man had been targeted just six hours after the shooting.
Scotland Yard later said that the officer alleged to have believed that "has categorically denied this in his interview with, and statement to, the IPCC investigators".
"This has also been corroborated by other staff in the private office," the statement continued, "We are satisfied that whatever the reasons for this suggestion being made, it is simply not true."
Mr Paddick, a Deputy Assistant Commissioner, told BBC Home Affairs Correspondent Danny Shaw that he was the officer who made the original statement to the IPCC.
He said that his interpretation of the Met response was that it accused him of lying.
Meanwhile the Metropolitan Police Authority (MPA), which oversees the force, is investigating another Met officer's complaint that Mr Paddick disclosed "confidential police information" to a journalist.
"Following consultation with the IPCC we are beginning preliminary inquiries," an MPA spokesman said.
An IPCC spokeswoman added: "We received a referral from the MPA relating to the conduct of an Association of Chief Police Officers rank officer.
"This has been assessed and we have passed the matter back to the MPA for them to deal with."
Mr Paddick said it would be "inappropriate" to comment on the investigation until inquiries had been concluded.