Ulster Unionist leader Mr David Trimble tonight blamed republican intransigence for the continuing deadlock in the Northern Ireland peace process.
Mr Trimble, who cut short an investment trip for crunch talks with the Prime Minister Mr Tony Blair, in London, expressed disappointment at the lack of progress over policing and IRA decommissioning.
With elections fast approaching, he warned the window of opportunity to resolve the impasse was closing.
"The difficulty is that republicans have been very, very slow to, in fact so far have made no effort at all to keep the promises they made in May of last year," he said after the meeting at Mr Blair's office in Westminster.
Despite intense discussions the parties to close the gap with nationalists on policing, demilitarisation and decommissioning, there is little sign of an imminent breakthrough.
Mr Blair had separate talks lasting 30 minutes each with Mr Trimble and the SDLP deputy leader, Mr Seamus Mallon, who has been spearheading his party's negotiations on police reform.
Mr Mallon refused to comment after his meeting with Mr Blair. His party is refusing to sign up to the new Police Board, arguing the British Government's reforms haven't gone far enough.
Afterwards, Downing Street would say little about their discussions or whether any progress has been made.
"There is real engagement going on here on the issues. The parties are focusing on the outstanding areas and doing so in good faith," a spokesman for the Mr Blair said.
Mr Trimble and Mr Mallon had broken off from a high-level visit to France and Germany, intended to promote inward investment to the Province, in order to attend today's meetings with Mr Blair.
Earlier it was confirmed that a planned British-Irish council meeting due to be held in Dublin on Monday had been postponed for a second time to give officials more time to try to hammer out a solution.
There is a growing belief that Mr Blair may return to Belfast next week in the hope of finally pushing through an agreement.
PA