SDLP leader Mark Durkan hopes to challenge the British prime minister Tony Blair in the Commons later today over Sir Ronnie Flanagan's continuance in post as Her Majesty's Chief Inspector of Constabulary.
Party sources confirmed Mr Durkan's intention to raise the issue during Prime Minister's Questions if called by Mr Speaker Martin, having already told Mr Blair that "if Ronnie Flanagan does not go, he should be dismissed".
In a statement yesterday Sir Ronnie, a former chief constable of the RUC, insisted he had no knowledge of the collusion between police under his command and members of the UVF in north Belfast reported in Monday's report by the Police Ombudsman Nuala O'Loan. He told the BBC he hoped anyone involved in such activities would be prosecuted.
But Mr Durkan insisted: "Ronnie Flanagan's defence that he did not know what was going on fools nobody.
"As the Police Ombudsman said, this could not have happened 'without knowledge and support at the highest levels of the RUC'. That means Ronnie Flanagan."
Mr Durkan also said Mr Blair had "serious questions" to answer "because collusion happened on his watch - not just on Margaret Thatcher's."
Disclosing that he had already written to Mr Blair demanding Sir Ronnie's departure or dismissal, Mr Durkan said: "I warned Tony Blair that Ronnie Flanagan's appointment as Inspector of Constabulary would come back to haunt him." He added: "Today it has."
Mr Durkan said he was also demanding "an undertaking that justice will now be allowed to take its course". He also warned of any "sweetheart deal" between the British government and Sinn Féin "to cover up the past" with legislation to provide amnesty for fugitive or on-the-run suspects.
"The public are entitled to know the truth about what happened over the last 30 years," he said.
Sir Ronnie said he utterly rejected any suggestion that he had been "in any way evasive or unhelpful" to the ombudsman's inquiry.
"On the contrary," he said, "at no time during the investigation or since did any member of the ombudsman's staff express to me any reservations about my personal action or conduct in any post that I held."
Sir Ronnie, who headed Special Branch before becoming chief constable, also strongly asserted: "With respect to the specific matters dealt with in the ombudsman's report, at no time did I have any knowledge, or evidence, of officers at any level behaving in the ways that have been described."
He declared: "I would find such conduct to be abhorrent, and if such behaviour took place my hope would be that it would be the subject of criminal or disciplinary proceedings."
Downing Street has been encouraged by Sinn Féin's willingness to use the findings of the report in support of its proposed backing for the PSNI, subject to conditions set out in the motion for Sunday's special ardfheis.