DUBLIN (AP) -- British prosecutors have charged a 61-year-old Irishman with the 1982 IRA attack on the queen's cavalry in Hyde Park, a nail-bombing at a top London tourist attraction that left four soldiers and seven horses dead.
Wednesday's surprise arraignment of John Downey in a London court came on the 15th anniversary of the ratification of the Good Friday peace accord for Northern Ireland, which sought to end three decades of bloodshed over the disputed British territory.
British authorities declined to explain why they arrested Downey as he arrived Sunday at London's Gatwick Airport nearly 31 years after the attack.
Sinn Fein demanded Downey's immediate release. The Irish nationalist party accused Britain of violating an agreement not to pursue Downey, who had been on a list of IRA suspects "on the run" from British investigators.
Sinn Fein official Gerry Kelly called Downey's arrest "vindictive, unnecessary and unhelpful" and an act of "bad faith" by the British government. The party said Britain should no longer be pursuing Irish Republican Army suspects in keeping with the spirit, if not the letter, of the 1998 Good Friday pact.
The IRA's main faction, the Provisional IRA, killed nearly 1,800 people during a failed 1970-1997 campaign to force Northern Ireland out of the United Kingdom. Anti-terrorist police in London and Northern Ireland, including a special "cold cases" unit, have continued to investigate unsolved IRA killings despite the Provisionals' 2005 decision to renounce violence and disarm.
These sporadic arrests of IRA veterans, often with Sinn Fein ties, have repeatedly raised tensions in the peace process, which remains incomplete as IRA splinter groups continue to mount occasional bombings and shootings.
Kelly, who led the IRA's first car-bomb attacks on London in 1973, said Downey had received a 2007 letter from Britain's Northern Ireland Office saying he was not wanted for questioning by any British police force and had traveled to London many times since then. Britain's Northern Ireland Office declined to comment on this.
In 2001, Britain agreed to give IRA fugitives from justice an amnesty so they could return to Northern Ireland without fear of arrest and prosecution, but the government later reneged because lawmakers refused to back the deal.
In court on Wednesday, Downey offered no plea and spoke only to confirm his identity as he faced four charges of murder and one count of conspiring to cause an explosion.
He is the third man to face trial for the July 20, 1982, twin bomb attacks on troops engaged in entertainment and ceremonial duties in London, one of the most audacious operations ever mounted by the Provisional IRA.
The Hyde Park bomb, planted in a parked car, was detonated by remote control as the mounted troops trotted toward Buckingham Palace in a daily tourist event.
Two hours later, a suitcase bomb hidden inside a bandstand in nearby Regent's Park killed seven army musicians during a performance. Concertgoers said the musicians were blown into the air. Twenty-two people, mostly soldiers, were wounded in total.
Prosecutors did not explain why Downey was charged in connection with the Hyde Park bomb but not the Regent's Park one.
If convicted, Downey would face parole within two years under terms of the Good Friday pact, which paved the way for hundreds of Provisional IRA members to walk free from prison from 1998 to 2000.
"Clearly if John Downey had been arrested and convicted previously, he would have been released under the terms of the Good Friday agreement," Kelly said.
In 1987 a Northern Ireland man, Danny McNamee, was convicted of conspiring to cause both blasts and received a 25-year sentence based on fingerprint evidence collected from the remnants of a bomb. But London judges in 1998 quashed the conviction, noting that prosecutors had withheld stronger forensic evidence of fingerprints implicating a senior IRA bomb-maker, Dessie Ellis.
Ellis today is a Sinn Fein lawmaker in Ireland's parliament in Dublin. He was extradited to Britain in 1990 to face charges of building both bombs, but he was acquitted on the grounds he had already served eight years in prison for related charges in Ireland. Ellis had been convicted of possessing multiple power-timer units for IRA bombs, including those suspected of being used in the Hyde Park and Regent's Park blasts.
The double bombing in London represented one of the IRA's biggest killings of British troops, but public attention was also drawn to the fate of the horses. One died in the explosion and six maimed animals were shot to put them out of their misery.