A victim of a bombing in Northern Ireland which killed 29 people has called for sanctions against those who designed a government scheme for handling fugitive republicans.
A secret peace process plan agreed between Sinn Fein and the last Labour government saw around 200 letters of assurance sent to on-the-runs telling them they were not wanted by UK police but not ruling out future prosecutions if new evidence emerged.
Michael Gallagher lost his son Aiden, 21, during the 1998 Real IRA blast which devastated the Co Tyrone town of Omagh and said murderers could take advantage of official weakness.
He said: "The people that were responsible, the agents of the government responsible for putting this (administrative scheme) together, they should have to face some sort of sanction for doing this.
"The most basic denial of human rights that victims can get is the denial of justice."
He said it was important to deter others.
"The people currently murdering in our country, they see that the Government is weak and willing to bend, 'if we kill enough people they will talk to us'."
Mr Gallagher gave evidence to the Northern Ireland Affairs Committee of MPs in London, which is investigating after the collapse of the case against a man accused of the 1982 IRA Hyde Park bombing which killed four soldiers.
John Downey, 62, from Co Donegal, was among those who received letters under the government's administrative scheme. In his case it wrongly assured him he was not wanted when, in fact, the Metropolitan Police were looking for him.
Mr Gallagher told the MPs: "As for the on-the-runs, I am not in the least interested in their politics. I am concerned about truth, justice and dignity for those who have suffered. By sending letters of assurance, the possibility of justice is denied to many victims and their basic human rights have been ignored.
"We represent some very unhappy people who put their faith in Parliament, politicians, police and the legal system. There seems to be no accountability mechanism working which stops politicians from ignoring the wishes of Parliament."
He added: "It appears the government were willing to do anything to placate the terrorists to the detriment of the victims.
"We are asking your help and support to hold those politicians to account for the untold damage they have done to victims and survivors by deceit and compounding their grief."
Also giving evidence to the Westminster hearing were Julie Hambleton and Brian Hambleton, members of Justice4the21, which is campaigning on behalf of the Birmingham pub bombing victims.
Ms Hambleton, whose sister Maxine was killed in the November 1974 blasts, said she received no response from senior politicians after raising the case with them.
She described her reaction to the collapse of the Downey prosecution in vivid terms.
"I felt like I was going to implode and turn to dust."
Ms Hambleton told the committee: "This is the nadir of our justice system without any shadow of a doubt. What is the point in politicians setting legislation to not follow it? What is the point in having law in the first place if no one is going to follow it?"
MP Ian Paisley said she had kicked over a "stone of maggots" during her evidence.
Twenty-one people were killed and 182 injured when two bombs exploded at the Mulberry Bush and the Tavern in Birmingham.
Earlier this year, after re-examining evidence, police said there would be no new inquiry.