John Clark, Jonathan Ganesh and Barry Laycock were suing Mr Adams in the High Court in London on the basis of his alleged affiliation with and leadership role in the Provisional IRA, which he has long denied.

They sought “vindicatory” damages of just £1 each, but withdrew their claim on Friday after the judge overseeing the trial said he would hear arguments as to whether the proceedings amounted to an “abuse of process”.

In a statement, McCue Jury & Partners LLP, representing the three claimants, said its clients had accepted an offer from Mr Adams “to settle the case on a drop-hands basis”.

The firm said the trial judge’s decision to raise the abuse of process issue “resulted, for the first time, in a real risk that the claimants, vulnerable victims of terrorism, could face devastating personal liability for legal costs”.

A finding of abuse of process “would remove the claimants’ costs protection and require them to pay Mr Adams his full legal costs”, the firm added.

“Due to this extraordinary series of events, and faced with even a small risk of life-changing financial consequences, the claimants had no realistic choice but to accept the defendant’s offer,” it said.

Mr Adams said the decision “brings to an emphatic end a case that should never have been brought”.

“I contested this case and defended myself against the smears and false accusations being levelled against me,” he said.

“I asserted the legitimacy of the republican cause and the right of the people of Ireland to freedom and self-determination. I do so again.

“During my two days of evidence I categorically rejected all of the claims being made.

“I am glad to have been one of those who helped bring an end to the conflict.

“We now have, through the Good Friday Agreement, a peaceful and democratic route to a new Ireland. That needs a renewed focus, especially by the Irish government.

“An Ireland that is respectful of all of its people and that is based on equality, tolerance and respect.

“I want to thank all of those who have expressed their solidarity with me and the Sinn Féin team which worked closely with me. I especially want to thank Colette and our family.

“Buiochas mór to my legal team for their exemplary work.”