A former Special Branch chief named and attacked in Parliament has said he has a letter of thanks that shows retired officers did cooperate with Nuala O'Loan's collusion probe.
SDLP boss Mark Durkan used parliamentary immunity to say that Chris Albiston, Ray White and Freddy Hall "failed to cooperate with the Police Ombudsman's investigation".
The probe revealed UVF killers committed at least 10 murders while being paid as agents.
Mr Durkan said that situation was "a disgrace" and said two of the officers "now attack her report and her office".
Mrs O'Loan's report said the "main difficulty" in her investigation was the lack of cooperation from former officers.
She said retired senior Special Branch officers "could have assisted this enquiry" but "refused to do so".
"Among those who refused were two retired assistant chief constables, seven detective chief superintendents and two detective superintendents," it said.
Mr Albiston, a retired assistant chief constable, said he and other retired officers had written to Mrs O'Loan "with information that would assist her investigation and looked to address specific points".
The officers have previously indicated that they turned down the Ombudsman's request to discuss the investigation in person.
Mr Albiston said that 18 months after police wrote back to Mrs O'Loan, it " became apparent that a critical report was being prepared".
He said the officers "asked to see the content and the nature of the allegations being made".
"There was no cooperation from her office on this point and officers were unable to see her report until Monday," he said.
"We earnestly hope that the reopening of the murder investigations will lead to the conviction of the guilty and are more than happy to help the police investigations in any way we can. However, it is important that we put the record straight and that responsible people understand that cooperation was offered and indeed we even have a letter from her office thanking us for our assistance."
During prime minister's questions, Mr Durkan also attacked former RUC chief Sir Ronnie Flanagan, accusing him of presiding over a culture of " anything goes but nobody knows".
He asked whether Sir Ronnie was now credible in his high profile job as the Home Secretary's principle advisor on policing.
Mr Durkan told Mr Blair that anywhere else the revelations exposed by Ms O'Loan would be a "national scandal".
He asked Mr Blair to "rethink plans to install MI5 as Continuity Special Branch", saying the agency will be "beyond the reach of key powers of the police ombudsman."
The prime minister said that he disagreed with the SDLP leader's analysis of MI5.
He then added: "Of course we deeply and bitterly regret any collusion that has taken place and impropriety on behalf of anyone who was working for Special Branch throughout those years.
"I am sure that he would want to acknowledge that as a result of those changes that were made some years ago that cannot happen anymore. It is precisely as a result of the additional scrutiny that we now have that this has been uncovered and laid bare."
DUP MP Jeffrey Donaldson said more than 300 police officers lost their lives. "Thousands of those officers, including Special Branch, saved countless lives," he said.