The outcome was happier than his attack on a Provisional IRA funeral in 1988, when he killed three mourners, including an IRA member.

Television cameras caught Stone firing a pistol and throwing grenades before he was rescued from a mob by RUC officers. He later said that his intention was to assassinate Gerry Adams and Martin McGuinness.

Both of his targets were inside the Stormont building today with the Reverend Ian Paisley. The business was to take another step towards power-sharing. Stone's 'protest' seemed to have been aimed at both sides of Ulster's polarised political class.

In 1989 he was sentenced to a 684-year sentence for six murders (while in custody for Milltown he admitted to three other murders of men he claimed were IRA members but who were Catholic civilians).

But he served less than 11 years. In July 2000 he released from the Maze prison, along with hundreds of other convicted terrorist murderers, as part of the Good Friday Agreement.

He was greeted as a hero by loyalists and the jacket which he wore during the Milltown attack was auctioned for £10,000 at a Scottish loyalist club. One of Stone's successors in the UFF, Johnny 'Mad Dog' Adair, said that Stone inspired him to join the terrorist group.

During his incarceration he was the leader of the Ulster Freedom Fighters and was visited by Mo Mowlam, the Northern Ireland Secretary, who reassured loyalist prisoners about the course of the peace process.

He has collaborated in the writing of two books about his life - one of the reasons why the Government said earlier this month that it will introduce legislation to prevent criminals from profiting from their crimes.

David Hanson, the Northern Ireland criminal justice minister, said: "It is not only distasteful but contrary to the principles of natural justice that they should be able to exploit for financial gain crimes that have devastated the lives of victims and their families."

Stone, 50, was born and raised on the hardline loyalist Braniel estate in east Belfast. He joined the Tartans, an infamous loyalist group, when he was 13. By the age of 16 he had already been held in Belfast's Crumlin Road jail for possession of firearms and membership of the Ulster Defence Association.

He said he hatched the idea for Milltown after the IRA bomb killed eleven people attending a Remembrance Sunday service at the cenotaph in Enniskillen, Co Fermanagh, in 1987.

Since his release he has earned a living as an artist, painting large expressionist works in primary colours and gloss paint. He has been fodder for the local newspapers, suggesting that at times he craves the limelight.

Earlier this month he claimed that Ken Livingstone was minutes away from execution, after stalking him for two days during the 1980s while the GLC leader was a vocal supporter of the Troops Out movement.

He is said to divide his time between Belfast, London and Spain. He has nine children from two marriages but now shares his life with a girlfriend with whom he has exchanged Christmas gifts of body armour, claiming that his life is still in danger from enemies, loyalist and republican.

Last year he took part in Facing the Truth, a BBC series in which victims were brought together with the perpetrators of their suffering. Sylvia Hackett talked with Stone, who was convicted of murdering her husband Dermot, a Catholic delivery man.

Although he previously admitted to the murder, Stone told his victim's widow that he had no direct responsibility, having been withdrawn after planning the attack. At the end of their meeting she forced herself to walk over to Stone and shake his hand.

When he placed a second hand on hers, she recoiled and fled from the room.

On another occasion he said of his crimes: "If I was to say sorry, I believe it would fall on deaf ears. I would be called a hypocrite. Those operations were military operations. I do not regret any fatalities that have occurred." This year he has been questioned by police about weapons procurement and other terrorist-related offences during the Troubles. "I just sat there, silent, and stared at a spot on the wall,' he said later.

Under the Good Friday Agreement, a terrorist prisoner's licence can be revoked if he or she re-offends.

After today's events, with their chilling echoes of 1988, it seems certain that Stone will be back behind bars for a long time.

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