A loyalist fanatic plotted to slit the throats of Gerry Adams and Martin McGuinness in front of television cameras inside the Northern Ireland Assembly chamber, a court was told yesterday.

Michael Stone considered the Sinn Fein leaders to be “republican war criminals” who did not deserve to be in government, Belfast Crown Court was told. His attempt to break into the Stormont assembly ended after security staff spotted he was a danger and detained him at the entrance.

Stone, 53, who denies attempting to murder Mr Adams, Sinn Fein’s president, and Mr McGuinness, the Deputy First Minister, claims that his activities on November 24, 2006, were in fact “performance art”.

He has also been charged with possessing home-made explosives and an imitation gun with intent, carrying a garrotte, three knives and an axe, and assaulting staff members, all of which he denies.

Charles Adair, QC, for the prosecution, said that Stone had said after his arrest: “My intention was to walk into the debating chamber and look for where Adams, McGuinness and Sinn Fein were sitting. I would have lobbed several nail bombs to cause confusion. I planned to stab Adams and McGuinness and cut their throats.”

Stone allegedly told police: “I see Adams and McGuinness as republican war criminals. Adams and McGuinness don’t deserve to be in a devolved government. It would be a bastardisation of democracy.”

Stone, who suffers arthritis and walks with a stick, spent two hours working his way through Stormont’s grounds, the court was told.

A security guard spotted him spray-painting the words “Sinn Fein, IRA, war” on the front of the buildings, the court was told, and challenged him. Stone allegedly pulled out a replica gun and pointed it directly at guard’s face, but on trying to enter the main revolving door, he was trapped by another guard.

He then flung a bag into the entrance hall, shouting that a bomb would go off in five minutes. The device never went off. Police believe that it was damaged in rain that fell that day.

Mr Adair said that Stone had made a trip to the countryside to test a bomb similar to the one on which he had lit the fuse. It had exploded in 21 seconds, he told the court.

Stone gained notoriety in 1988 when he was caught by television cameras attacking a funeral for three IRA members shot by the SAS in Gibraltar. He killed three mourners and injured several more at Milltown Cemetery in West Belfast. He was caught by police while running away.

He had been released from prison under the terms of the Good Friday Agreement but after his arrest at Stormont he was returned to prison to serve out the balance of his life sentence for the murders.

The court was told that a recording of the events at Stormont had recently come to light and would be shown during the trial.

Arthur Harvey, QC, who is defending Stone, said that the DVD would back his client’s claim that his actions at Stormont were “performance art”.

The case has been adjourned until next week.

Times Recommends

• Donor organ allowed child’s own heart to heal
• Michael Jackson: Not the final chapter
• Brüno toned down for 15 rating