Former Ulster Unionist Party (UUP) leader David Trimble has blamed republicans and the two governments for the collapse of his party's vote in last week's Westminster elections.
He also predicted a stalemate in efforts to restore powersharing in Northern Ireland and said the Rev Ian Paisley's Democratic Unionist Party (DUP) would be unable to strike a deal with republicans.
The UUP secured only one seat in the House of Commons, compared to the DUP's nine. Mr Trimble, who lost his own seat in Upper Bann, resigned as leader at the weekend.
Speaking at a press conference in Belfast this morning he said there was "no other course" for him to take after the election result but said he had no regrets about the strategy he took.
"Clearly the most important thing that happened was the negotiation of the Belfast agreement. . . . I have not regrets about the strategic position or the approach or about the fundamentals of the agreement.
"I'm quite sure that the future development of Northern Ireland is going to be based on the that agreement, give or take a little bit here or there," he said.
But he said the agreement was never properly implement by republicans. "If they had implemented the agreement then they would have disarmed by May of 2000," Mr Trimble added. "That is the basic cause for the shift that has taken place in unionist opinion.
"The other factor is that the government, primarily our own government but to an extent also the Irish Government, were seriously at fault in not upholding the principles of the agreement.
"I see unfortunately there is the likelihood of a significant stalemate here until the [British] government changes it approach, until republicans change the way that they ought to and there's no point people turning around blaming unionism for voting they way that it has when that vote was a not unreasonable reaction to the failures of others."
Mr Trimble said the DUP were unable to make an agreement on powersharing late last year. "My own personal view is that we are likely to see a similar breakdown from the DUP in the future if they do indeed engage in negotiation, and that must be an open question."
Mr Trimble said the new Northern Ireland Secretary, Peter Hain, had gotten off on the wrong foot.
"The fact that government is still not putting pressure on the republican movement is ... a mistake," he said. "Peter Hain will be a failure unless he changes his
approach."
After arriving in Belfast today, Mr Hain said: "The first thing is to give an absolutely crystal clear signal that we cannot continue to be bogged down as we have been
in a stalemate."
Taoiseach Bertie Ahern, who joins over 50 other world leaders in Moscow this morning as part of the Victory in Europe Day commemorations, said he was optimistic about reaching a political solution in the North.
"If we can make the progress that we have requested of the parties to deal with the issues of decommissioning, to deal with the issues of criminality and move to a new future and the IRA stepping aside, then we can make a lot of progress," he said.
