The families of four soldiers killed in the Hyde Park bombing 37 years ago are beginning a fresh legal challenge.
Relatives of the Household Cavalrymen who died in the July 1982 blast are bringing a damages claim at the High Court against John Downey, from County Donegal.
Squadron Quartermaster Corporal Roy Bright, 36, Lieutenant Dennis Daly, 23, Trooper Simon Tipper, 19, and Lance Corporal Jeffrey Young, 19, were killed by a car bomb as they rode through the central London park to attend the changing of the guard at Buckingham Palace.
Mr Downey has always denied any involvement in the attack and has said he has no intention of taking part in the latest proceedings at the Royal Courts of Justice.
The trial to prosecute Mr Downey for the Hyde Park bombing collapsed five years ago after it was revealed that he had received a written assurance from former prime minister Tony Blair's government that he was no longer wanted.
The letter was issued under the terms of the controversial On The Runs (OTRs) scheme.
Relatives of the four soldiers have been given public funding to press for damages in their civil claim.
The case is set to last three days.
(Cover image: Two burned-out vehicles in the aftermath of the Hyde Park bombing on 20 July 1982. Picture: PA).