The attack not only took two lives but could have the potentially catastrophic effect of bringing to an end a loyalist paramilitary ceasefire which already looked fragile.
It has already had the effect of severing contact between the government and Sinn Fein, Tony Blair declaring: "There is obviously no question of a further meeting with Sinn Fein in these circumstances." Officials were due to meet Martin McGuinness in Belfast today for a third and final meeting in a series sanctioned last month by Mr Blair.
The killings, coming as they did in the Co Armagh town of Lurgan which is not far from the Drumcree marching flashpoint, can only be described as an act of extreme provocation. Tensions in the mid-Ulster area were already high as the 6 July march date approaches with no sign of agreement on whether the parade should be allowed through a sensitive Catholic area.
The two RUC men were shot in the head at close range not far from a police station while on routine beat patrol. They have been named as Constable John Graham, who was married with three daughters, and Reserve Constable David Andrew Johnston, who was married with two sons.
The Prime Minister said in a statement after a brief conversation with John Bruton, the Irish Prime Minister, on the fringe of the European summit at Amsterdam, that he reacted with horror and anger at what looked like "a deliberate attempt to place obstacles in the road of peace."
Mr Blair said that whilst Sinn Fein talked peace, the IRA murdered: "Their cynicism and hypocrisy are sickening. Their actions defy normal understanding. It is difficult to interpret this latest attack as anything but a signal that Sinn Fein and the IRA are not interested in peace and democracy, and prefer violence."
Gerry Adams, the Sinn Fein president, adding a new word to his political lexicon, said he was "shocked" by the deaths. He declared: "At a personal and at a human level I am shocked."
His reaction was echoed among many other observers, including republican sympathisers and their opponents. The government had been making clear moves towards meeting republican concerns on ensuring that Sinn Fein would be admitted to political negotiations in the event of a new IRA ceasefire.
But the effect of the killings has been to end contacts with the Government, and to leave the huge unanswered question of how the IRA believes that such acts can advance the republican aim of securing entry into talks.
The mood among loyalist paramilitary groups, who have observed a worthwhile though imperfect ceasefire, was said to be grim, and the security forces will be braced for retaliatory attacks. David Adams of the Ulster Democratic Party, which is close to the paramilitary Ulster Defence Association, warned: "The future looks dark. We have to face the reality this may well push loyalists to the brink."
Loyalist acts of violence could lead to the expulsion of their political representatives from the existing multi-party talks, thus decreasing the chances of their success. In the meantime Unionist politicians called on the Government to abandon hopes of bringing Sinn Fein into politics.
Ken Maginnis, the Ulster Unionist MP, said: "Republicans have been playing a mocking game with successive governments and testing the integrity and sincerity of the new Labour government in order to ascertain how far it could be pushed. It's now imperative that all governments who have tried to move things forward must realise that the IRA is irredeemable."Reuse content