Scotland Yard has vowed to fight claims a senior officer "tricked" a Commons official into allowing the controversial search of an MP's Parliamentary office.
The Metropolitan Police said it had evidence to disprove the allegations which were revealed by ex-Speaker Michael Martin to an inquiry into the Damian Green affair.
Tory immigration spokesman Mr Green was arrested and his offices raided last year in a highly-criticised police investigation of leaks from the Home Office.
The Crown Prosecution Service (CPS) announced in April that Mr Green and a mole at the Home Office who passed him sensitive documents would not face prosecution.
MPs reacted with fury to the search of his Commons office and the handling of the issue contributed to the pressure which eventually forced the Speaker to quit his office.
Giving evidence to a committee of senior MPs, Lord Martin - who was made a peer after stepping down as an MP - denied responsibility for the controversy.
He placed the blame at the door of two senior officials, the Serjeant at Arms and the Clerk, for failing to inform him the police had no warrant for the search. Instead it was carried out on the basis of a consent form signed by the Serjeant Jill Pay.
But Lord Martin also revealed that the Clerk, Malcolm Jack, had defended their actions on the basis of alleged underhand tactics by the police.
Chief Supt Bateman is the officer in charge of Commons security. Asked if he believed the police had targeted the consent of the Serjeant because they did not think they would be able to secure a warrant, he said: "We have a word in Scotland called 'sleekit' and they were being sleekit, they were doing it in a sleekit way to get in."
Scotland Yard immediately issued an angry denial and said it would prove to the committee that there was no substance to the allegations against the officer.