The British and Irish prime ministers are to pile the pressure on the IRA to disarm, disband and face up to the latest crisis threatening Northern Irelands peace process.

Downing Street sources are pessimistic that republicans will back down and suspension of the power-sharing Northern Ireland assembly and executive is expected next week.

The next two days are crucial to the future of the peace process and Tony Blair will demand action from the IRA as a last bid to restore trust after a republican spy ring scandal at the heart of Stormont.

Blair will meet Bertie Ahern tonight in a united effort to wring concessions out of Sinn Fein chief, Gerry Adams.

Ireland may press for new elections in the province, a move that will rejected by Britain - concerned that it could trigger deeper sectarian divisions at a time of high tension.

Adams will meet Blair at Number 10 on Thursday.

David Trimble met Blair yesterday to press the government to expel Sinn Fein's two ministers from the 12-man Stormont executive.

The moderate Ulster Unionist leader has demanded that Sinn Fein only be readmitted after the IRA is disbanded.

He called for Blair to send an expulsion motion for debate in the assembly.

"In the event of that not happening by Monday or Tuesday, that will leave us with no alternative but to remove ourselves from the administration," he said.

The UUP has set Downing Street a one week deadline before he join's Ian Paisley's hardline Democratic Unionist Party in a walkout from the power-sharing government

Writing in today's Daily Mirror, former northern Ireland secretary Peter Mandelson argues that the province's voters should decide on Stormont's future.