Hyde Park
Four members of the Household Guard were killed in the Hyde Park bombing in July 1982Reuters

Irish Republican terror suspects who were given "comfort letters" by the British government will still face arrest if police find sufficient evidence against them, a review has found.

The inquiry into the controversial On the Runs scheme, (OTRs), set up by Tony Blair's Labour government and Sinn Fein, found it "did not amount to an amnesty" or "get out of jail free card" for terrorists.

Speaking in parliament on the conclusions of the inquiry, Northern Ireland Secretary Theresa Villiers said: "The Government has always been clear that if sufficient evidence emerges, then individual OTRs are liable for arrest and prosecution in the normal way.

"So I repeat again today to the people holding these letters, they will not protect you from arrest or prosecution and should the police succeed gathering sufficient evidence, you will be subject to due process of law."

Around 200 IRA suspects - of whom 95 are reportedly linked to 295 murders in the Troubles - received assurance letters they would not be prosecuted for their political crimes in the wake of the Good Friday Agreement in 1998.

Lady Justice Hallett, who led the inquiry, admitted the scheme was "flawed" but ruled out it was "unlawful".

She said: "The administrative scheme did not amount to an amnesty. Suspected terrorists were not handed a 'get out of jail free card'."

A review of the scheme was only ordered following the collapse of the trial of 1982 Hyde Park bomb suspect John Downey, who had been sent one of the letters in error by the Police Service of Northern Ireland, (PSNI). Officers' failure to act when they realised their mistake was blasted by Hallett as "inexplicable in law and logic".

The judge found that had the scheme been properly administered Downey would not have received a letter.

The Downey case triggered a crisis in Northern Ireland leading the Democratic Unionist First Minister Peter Robinson to threaten resignation claiming he knew nothing about the letters.