London ? The British government Monday suspended the landmark power-sharing assembly that had been set up in Northern Ireland, dealing a grave blow to the 1998 Good Friday peace accords.

The decision, which took effect at midnight Monday, means that the British government will once again assume direct control over the affairs of Northern Ireland, replacing the coalition government that had brought Protestants and Catholics together.

The immediate cause of the suspension was Protestant politicians’ fury about revelations that the Irish Republican Army had used its political wing, the Sinn Fein party, to set up a spying operation at the heart of the coalition government that gave the IRA access to confidential information.

The IRA spying operation, unmasked Oct. 4 when police stormed Sinn Fein’s offices at the imposing government building known as Stormont, prompted First Minister David Trimble, leader of the influential Ulster Unionist Party, to threaten to pull his party out of the coalition today if the IRA did not make a major concession toward peace.

Trimble had called for the British government to expel Sinn Fein from the government, because of its role in the spying scandal, rather than suspend the government entirely.

The British government, with the full support of the Irish government in Dublin, decided instead to shut down the coalition before it collapsed with the hope that the institutions can be put back in place within several months when tempers cool, officials said.