A man whose trial over the IRA’s Hyde Park bomb collapsed in controversial circumstances has been arrested on suspicion of the murder of two soldiers in Northern Ireland in 1972.

John Downey was detained by Irish gardai on Monday evening under a European Arrest Warrant as part of a joint operation with the Police Service of Northern Ireland (PSNI).

Mr Downey, 66, was arrested in Co Donegal and is expected to appear at Dublin High Court on Tuesday afternoon to face extradition proceedings.

Prosecutors in Northern Ireland have decided there is sufficient evidence to prosecute him for the murders of Lance Corporal Alfred Johnston, 32, a father of four, and Private James Eames, 33, a father of three, in Co Fermanagh.

They died when an IRA bomb exploded in a car they were checking on the Irvinestown Road, Cherrymount, Enniskillen on August 25, 1972.

In 2013, John Downey was charged with murdering four Royal Household Cavalrymen in a bomb in London’s Hyde Park in 1982.

He stood trial at the Old Bailey, but the case dramatically collapsed after it was revealed he had received a written assurance from former prime minister Tony Blair’s government that he was not actively wanted by the authorities.

The letter was issued under the terms of the controversial On The Runs (OTRs) scheme.

Hyde Park bombing High Court claim
The scene following an IRA car bomb blast in Hyde Park (PA)

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

The episode sparked a government inquiry into the OTR scheme.

Mr Downey has always denied any involvement in the Hyde Park attack.

The four soldiers killed in Hyde Park were Trooper Simon Tipper, 19, Lance Corporal Jeffrey Young, 19, Squadron Quartermaster Corporal Roy Bright, 36, and Lieutenant Anthony Daly, 23.

The IRA car bomb exploded as they made their way from their Kensington barracks to a Changing Of The Guard ceremony at Horse Guards Parade.

Announcing Monday’s arrest, Detective Chief Inspector John Caldwell, from the PSNI’s Major Investigation Team, said: “The PSNI has been liaising closely with An Garda Siochana and today’s arrest demonstrates the benefits of joint working between police forces and other national partner agencies.

“The PSNI investigation into these murders remains active.”

Northern Ireland’s Public Prosecution Service (PPS) confirmed on Monday a decision has been taken to prosecute a 66-year-old man for the Cherrymount murders.

A PPS spokesperson said: “Following careful consideration of all available evidence, a decision has been taken to prosecute one person for the offence of murder and for aiding and abetting the causing of an explosion.

“Extradition proceedings were initiated in the High Court in Dublin on Monday November 5, to seek the extradition of one man from the Republic of Ireland for trial in Northern Ireland.

“One man was subsequently arrested in County Donegal this evening and is due to appear in court in Dublin tomorrow.

“As proceedings are now live and before a Court, we will not be making further comment on this case at this point.”

The families of the two deceased have been kept informed of developments.