Lord Tebbit today called for the terms of an inquiry into secret letters sent to "on the run" IRA fugitives to be extended.
The Tory former Cabinet minister said this should be done "so we can know whether or not there were any letters or similar inducements given to assist the progress of the ceasefire talks, which led eventually to the Good Friday agreement".
He told peers at question time: "It is my understanding that certain proceedings were held up in order to assist that process. It would be interesting to know if that is indeed true."
Lord Tebbit survived the IRA's 1984 bombing of The Grand Hotel, Brighton, in which his wife, Margaret, was left injured and disabled.
The Government has appointed Lady Justice Hallett to conduct an independent review of the administrative scheme for dealing with on the runs (OTRs) after its emergence sparked outrage among unionist politicians.
In February, it came to light during the trial of John Downey, who was accused of murdering four soldiers in the Hyde Park bombing in 1982, that Irish republican OTRs had received letters stating that they were not wanted by police for paramilitary crimes committed before the 1998 Good Friday peace agreement.
Government spokeswoman Baroness Randerson, replying to Lord Tebbit, said the terms of reference had been set out and work had started.
"But I'm sure that if she were to come upon evidence that led her to be concerned about issues of the nature that you have referred to, it would be within her remit to make recommendations on that for the future."
Lady Randerson said the inquiry would provide a full public account of the operation and extent of the scheme and its report was due to be completed by the end of June.
Tory Lord Lexden said the sending of the secret letters to terrorist suspects had caused shock and outrage.
"Why on earth did this Government continue the shameful collusion with Sinn Fein by allowing more letters to be sent out by officials until the end of 2012?" he demanded.
Lady Randerson said that if ministers had been presented with a scheme which amounted to "immunity, exemption or amnesty", they would have stopped it.
She urged peers to await the outcome of the review to hear the full details.
Liberal Democrat former Northern Ireland spokesman Lord Shutt of Greetland asked why the inquiry had no powers to compel witnesses to give evidence.
Lady Randerson told him it was an "administrative review" and the Government had always had reservations about the use of full public inquiries to deal with issues in the past, which could take a long time.
"There is in this case a clear public interest in early publication of this report," she said.
Former Ulster Unionist leader and now Tory peer Lord Trimble asked if the review was to go ahead without hearing from the people "who designed the process" - including the then Northern Ireland secretary and Sinn Fein's Gerry Adams.
He questioned whether it was satisfactory to have an inquiry without the power to compel Mr Adams to give evidence.
Lady Randerson said Government officials would appear before the inquiry and give evidence. "Others will be invited to do so," she added.
It was entirely up to Lady Justice Hallett to decide who she would request evidence from and how far she took the scope of her inquiry.
For Labour, Lord McAvoy insisted the letters were not an amnesty but said news of their existence had drawn attention to the need for a long-term solution to issues of the past.
Lady Randerson said she understood the considerable anger stirred by events of the past few weeks.
"I'm sure that those who were in government during the earlier years of the OTR scheme will welcome the opportunity in due course to give evidence."
She confirmed that the letters did not grant immunity, exemption or amnesty.