Ulster Unionist leader Mr David Trimble has demanded closure, finality and an end to the republican movement's "love affair with the gun".
Demanding "proof, not promises", Mr Trimble emerged from Downing Street talks with the British Prime Minister, Mr Tony Blair, yesterday insisting that the onus was on Sinn Féin to provide the stability necessary to restore the Stormont Assembly and ensure that the institutions of government were never again placed at risk.
At the same time, he confirmed he had urged Mr Blair to have ready "a range of sanctions, including exclusion" to be deployed against Sinn Féin post any return to devolution "in response to any foot-dragging or failure by republicans."
Mr Trimble indicated that the Ulster Unionists would never again accept a suspension of devolved government as a result of a republican failure to honour the commitment to exclusively peaceful and democratic means.
While welcoming what he termed "a step change" in British policy in Northern Ireland, Mr Trimble also confirmed that his party delegation had pressed Mr Blair on the need for timetables and proper verification procedures for any disarmament process as part of the "acts of completion" demanded by the Prime Minister.
The Alliance Party leader, Mr David Ford, also reopened the question of a ceasefire monitor yesterday when he and his deputy, Mrs Eileen Bell, held separate talks with Mr Blair.
The Progressive Unionist Party leader Mr David Ervine was also in Downing Street yesterday at Mr Blair's request.
It is understood Mr Blair stressed his government's readiness to assist those loyalists choosing the political path, while insisting that the path to paramilitarism was closed.
Mr Ervine accused Sinn Féin of trying to "blackmail" the government on issues such as an amnesty for fugitive or "on the run" terrorists, but said Mr Blair had assured him no secret concessions were being offered to republicans.
Mr Trimble was accompanied by former Stormont ministers Sir Reg Empey and Mr Michael McGimpsey, as well as North Down MP Lady Sylvia Hermon. It is understood Mr McGimpsey and Sir Reg will travel to Dublin shortly for talks with the Minister for Foreign Affairs, Mr Brian Cowen.
In their statement afterwards, Mr Trimble and his colleagues said: "Our discussions served to underline the need to maintain pressure on republicans. We are not seeking great-sounding words or gestures, but finality. The Ulster Unionist Party, indeed, all the people of Northern Ireland, want to know that the republican movement have put up the shutters, have gone out of business, have ended their love affair with the gun." They demanded "certainty" that republicans would "not return to their bad old ways".