On the Runs: Norman Baxter accuses Downing Street of attempting to pervert the course of justice
A retired senior police officer has accused Downing Street of attempting to pervert the course of justice by asking for the release of republican suspects in March 2007.
Former Det Ch Supt Norman Baxter also has claimed there was "a culture within the Northern Ireland Office to ensure that republicans were not prosecuted".
He said the PSNI was scapegoated for the collapse of the John Downey case.
Mr Baxter was giving evidence to the NI Affairs Committee at Westminster.
It has begun an inquiry into the process for dealing with On the Runs, Irish republicans who had received letters stating that they were not wanted by police for paramilitary crimes committed before the 1998 Good Friday peace agreement.
The letters came to light in February when the trial of Mr Downey for the 1982 IRA Hyde Park bombing was halted because he had mistakenly received one of those letters.
Mr Baxter told the committee that Police Service of Northern Ireland Chief Constable Matt Baggott was wrong when he apologised and said he accepted the PSNI had made a mistake in the Downey case.
He said Mr Baggott had "reacted without knowledge", and described the apology as poor leadership.
He also criticised the chief constable for being prepared to "give up his force as a sacrifice to cover for the NIO".
Police in Northern Ireland had known that Mr Downey was still being sought by Scotland Yard whenever the NIO sent him the letter.
When his Old Bailey trial collapsed it emerged that about 190 other republicans had received similar letters.
Mr Baxter added: "I thought the secretary of state's [Theresa Villiers] statement was quite disgraceful in blaming the police without any due process.
"I honestly think that she, by doing so, was covering up for what was going on with this administrative process."
Mr Baxter also said that Sinn Féin president Gerry Adams had put pressure on Downing Street to ask for the release of two republican suspects in 2007.
Vincent McAnespie and Gerry McGeough, who were wanted for the attempted murder of part-time UDR soldier Sammy Brush in 1981, were arrested on 8 March 2007 and taken for questioning to the Serious Crime Unit at Antrim police station.
Mr Baxter said: "At 9.10pm I received a phone call from duty ACC at headquarters, Gerry Adams had telephoned Downing Street demanding their release.
"Downing Street rang the chief constable's office looking for their release and I got a phone call suggesting I should release them.
"That, in my mind, is attempting to pervert the course of justice and that was conveyed back to headquarters.
"As a police officer that is totally illegal and unconstitutional. We continued interviewing them and Mr McGeough was subsequently convicted and sentenced for attempted murder."
Mr Baxter said he did not know who made the phone call from Downing Street.
Mr Brush, who is now a DUP councillor said he was shocked, but not surprised by Mr Baxter's claims.
"From the revelations of the get out of jail free letters I expected there would be more to come and I still think there will be more revelations to come yet because I think the government has behaved very badly towards the victims of terrorism in this country," he said.
"The victims of terrorism seem to be expendable, but the terrorists had to be preserved."
Northern Ireland First Minister Peter Robinson said victims "must be outraged" by the evidence from the committee.
He said it showed the kind of pressure Sinn Féin could bring to bear.
Sinn Féin President Gerry Adams TD said it was a "matter of public record" that he had called for the release of the two men.
"I also protested to the British government," he said.
"I did not ask the British government to intervene with the PSNI.
"My protest at that time was entirely appropriate given that the British government had given commitments to resolve the anomaly of the OTRs.
"Mr Baxter's outlandish claim that the NIO was trying to avoid arresting republicans is nonsense and ignores the virtual amnesty provided to the British army and RUC for the killing hundreds of citizens."
In a statement, the Northern Ireland Office spokesperson said: "A full account of the facts will be produced by Lady Justice Hallett's inquiry in due course. We also anticipate giving evidence to NIAC (Northern Ireland Affairs Committee) shortly. We do not propose in the interim to provide a running commentary."
Former PSNI assistant chief constable Peter Sheridan also gave evidence to the committee.
He said that a police team that reviewed the On the Runs cases knew that Mr Downey was wanted by the Metropolitan Police, and more information should have been given to the trial judge.
"The judge should have been told that the PSNI officers were completely unaware that there were letters going out and that there was additional information put in the letter that went out that was different from the letter that we sent to the DPP (Director of Public Prosecutions)," he said.
Mr Sheridan said professionals in the NIO knew where the line constituting political interference was and did not cross it, as far as he was aware.
He also insisted police acted properly.
"The policing role in this was to test the evidence at that time, which is what the review team did.
"It would have been good if the judge had access to all of the facts and information.
"It is a matter of disappointment that we did not have the opportunity to put some of this information in front of the judge.
"I feel extremely sorry for the families. It is only going to add to the bewilderment and confusion about what was happening. At some stage we have to separate this whole past and deal with victims, and deal properly with victims."
An independent review of the On the Runs issue ordered by Prime Minister David Cameron is to be carried out by Lady Justice Heather Hallett, while the Northern Ireland Assembly's justice department is also investigating.
The chair of the Northern Ireland Affairs Committee, Laurence Robertson, explained the aim of the inquiry.
"The centre of it really is why there is a necessary, separate category for some people such as On the Runs," he said.
"What were people who were in that category suspected of having done, or what did they feel that they were suspected of having done so that they needed to put their names forward for this scheme.
"It really does beg the question why was it necessary to have such a scheme, why did so many people - over 200 it seems - feel the need to put their names forward for clarification of their particular status.
"Also the royal pardons that were received - we're looking very closely at that going forwards."