Former Prime Minister Tony Blair is set to be publicly grilled on his role in the on-the-run letters scandal.
Chairman of the Commons Northern Ireland Affairs Committee Laurence Robertson was scathing in his criticism of the handling of the cases by the British authorities.
He confirmed yesterday he is pressing for a separate inquiry carried out by the powerful body of MPs he chairs – and the former PM is in his sights.
The key difference between that and the judge-led review announced by Prime Minister David Cameron would be the power the committee has to make witnesses called to attend in person.
Mr Robertson said it was imperative all of those accused of being involved in brokering the murky deal were held to account – including Mr Blair.
As Prime Minister he offered the concession following the Good Friday Agreement deal and wrote to Sinn Fein president Gerry Adams requesting the names of suspects for consideration for the scheme.
"What we need to ensure is that the judge-led inquiry goes wide enough to explore all the aspects of the scheme: who ran it, who set it up," said Mr Robertson.
"It's not just about the Downey mistake, it's about the whole issue, the whole practice, that we want an inquiry on."
Mr Robertson said any committee inquiry would have the power to force people to attend, and would be conducted in public.
"One of the accusations made about the (letters) process was that it was secretive," he said.
"To further that secrecy in an inquiry would be to miss the point.
"I am concerned about some of the restrictions placed on the judge and that's something we will look at."
When asked if Mr Adams could be called before any affairs committee inquiry, Mr Robertson replied: "Anybody would be fair game.
"We feel enough has gone on for an inquiry, be it a judge-led one or a select committee inquiry.
"As I understand it, he couldn't be forced to attend, but it would look bad for anybody called who didn't."
He said the issue will be discussed by the committee next week.
It's also emerged there are five outstanding on-the-run cases involving republican terror suspects, with the Justice Minister vowing he will never have any part in dealing with the issue.
David Ford revealed he was told by a senior NIO official of the five cases still being considered.
The Belfast Telegraph understands he was furious when the Director of Public Prosecutions Barra McGrory revealed he was aware of outstanding cases.
Mr Ford distanced himself from the outstanding matters.
"The position with these five cases is very clear," said Mr Ford.
"After raising the issue both with the Secretary of State and the NIO, I can make it absolutely clear that the five cases in the system – because the NIO put them in the system – remain their responsibility, so this is not a devolved matter.
"The Department of Justice has no part in this scheme, never had any part in this scheme, and as long as I am minister will never have any part in this scheme."
Of the 187 suspects considered, 38 continued to be investigated following the devolution of justice powers to Northern Ireland in 2010.
Secretary of State Theresa Villiers admitted the failure not to inform the Northern Ireland authorities in 2010 was a flawed decision.
A spokeswoman for the NIO yesterday said: "The Prime Minister announced on Thursday that a judge would be appointed to provide an independent review of the administrative on-the-runs scheme by the end of May.
"The review will produce a full public account of the operation and extent of the OTRs scheme. It is important now that we let this inquiry run its course," she said.