The former Northern secretary, Mr Peter Mandelson, is donating £10,000 towards a campaign to sue the alleged perpetrators of the Omagh bombing.
Relatives of those killed in the explosion said Mr Mandelson, who resigned from the British Cabinet last month, was handing over the fees paid by national newspapers for articles explaining his handling of the Hinduja passports affair.
He has been recruited - along with another former Northern Secretary, Sir Patrick Mayhew - to front the Omagh Victims' Legal Trust. The trust is attempting to raise £1 million to bring a civil action against at least five men it claims were involved in the bombing.
A lower burden of proof is required in a civil case than in criminal proceedings. Twentynine people were killed in the "Real IRA" bombing in 1998.
One man, Mr Colm Murphy, has been charged in connection with the explosion. Mr Murphy, from Ravensdale, Co Louth, is awaiting trial in the Republic on a charge of conspiracy to cause explosions. The trial is expected to begin in October.
Mr Victor Barker, whose son James (12) was killed, said the £1 million had to be raised before the expiry of the three-year deadline for lodging a civil litigation claim. The deadline expires in August.
"We feel very committed to the cause, in terms of being able to bring a civil case which will be successful against a number of those we believe to have been either responsible or who had a major part to play in this tragedy," he said.
"The case is based upon extremely complex evidence, with masses of paperwork to be got through before a successful claim can be brought. Our advice from the lawyers acting for us is we need to have almost £1 million to be able to bring a civil claim successfully."
On BBC Radio Ulster Mr Barker said the case would seek financial compensation for the explosion. "This is an attempt by the relatives to get these people into court to have to answer questions and to say and give explanations for what they did on August 15th, 1998.
"It is a sense of justice and fair play the relatives want to see. Money is of no concern to any of us. It is a cry for justice. It is not a symbolic or `waving hands' action. This is a very serious matter as far as the relatives are concerned. Relatives of the victims are determined to ensure that someone has to answer some questions."
Mr Mandelson yesterday said pressure must be maintained on the "Real IRA" if the peace process is to move forward.
"The `Real IRA' are the last remaining obstacle to a successful peace process in Northern Ireland," he said. "There should be no hiding place for them. I applaud the efforts of the Omagh bereaved families and the courage they are showing in mounting their appeal."