The objective of the Hyde Park bombing was the “cold-blooded killing” of British soldiers, the High Court has heard.

Relatives of the four Royal Household Cavalrymen who died in the July 1982 blast are bringing a civil action against convicted IRA member John Downey.

Squadron Quartermaster Corporal Roy Bright, 36, Lieutenant Dennis Daly, 23, Trooper Simon Tipper, 19, and Lance Corporal Jeffrey Young, also 19, were killed by a car bomb as they rode through the central London park to attend the changing of the guard.

Lawyers acting for Sarah-Jane Young, L/Cpl Young’s daughter, in whose name the action is being brought, told a hearing in London that the families of those killed expect “justice” to be done.

At the start of a three-day hearing in London on Wednesday, Lord Brennan QC said: “Thirty-seven years after, if justice can properly be done, as it can be in this case, then let it be done.

“That will reflect the expectation of the bereaved families and the injured, it reflects the state of our law, it accords with the conviction of our community and the sentiment lying beneath it is deeply felt.”

He added: “Its (the bombing’s) objective was cold-blooded killing, with vicious brutality and maximum harm.

“The claimant’s case is that these devastating consequences were intended, including the murder of these four soldiers.”

The barrister said there was “clear” evidence of Downey’s involvement in the attack, including the fact that his fingerprints were found on two parking tickets used on the bomb car shortly before the explosion, adding: “That fingerprint evidence is damning against the defendant.”

Downey is not participating in the trial but has filed a written defence denying any involvement in the attack.

He was charged four years ago with the murders, but his prosecution at the Old Bailey collapsed in 2014.

Family members of those killed launched legal action against Downey after the collapse of the trial.

The relatives initially asked for help with legal fees through crowdfunding after being refused legal aid five times, but it was revealed in February last year that they had been granted public funding to pursue the case.

Speaking outside court ahead of the hearing, Sgt Tipper’s brother, Mark Tipper, said: “It’s a long time to fight for justice. It’s taken a long process. We are here now.

“We have had to fight the Legal Aid Agency, we’ve had to fight everyone.

“For me personally, it’s been a long campaign. It takes its toll on you.”

He added: “We all deserve justice.”

The car bomb left in South Carriage Drive killed the four soldiers as they travelled from their barracks to Buckingham Palace.

Two were killed instantly, while L/Cpl Young and Maj Bright died from their injuries within days. Thirty-one other people were injured.

Seven horses had to be put down and another horse, Sefton, survived terrible injuries.

The criminal case against Downey, from Co Donegal, dramatically collapsed 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.

Trial judge Mr Justice Sweeney ruled that Downey’s arrest at Gatwick Airport, as he passed through the UK on the way to a holiday in 2013, represented an abuse of process and he put a stay on any future prosecution.

Downey is currently in prison in Northern Ireland, facing a criminal prosecution for a car bomb attack which killed Ulster Defence Regiment members Alfred Johnston and James Eames in Enniskillen, Co Fermanagh, in 1972.

The High Court hearing, before Mrs Justice Yip, is to determine whether Downey is liable for the bombing.

If the judge concludes he is, a second stage of the case will consider the amount of damages to be awarded.