As bad weather delayed a crisis meeting between the Sinn Féin leadership and British Prime Minister Tony Blair until today, Gerry Adams said that "the ability of the Sinn Féin leadership and the two governments to devise a plan to sort out political crises has happened quite a few times in the last four years.

"Maybe it can be done again but even if we do that, the bar which the unionists have raised is very, very, very high indeed. I don't see any sense at this time of any section of unionism running into the elections prepared to engage on a pro-Agreement axis.

"It is my belief that these issues can be resolved, that the Agreement can be implemented. However, can this be done in the immediate time ahead? I don't know.

"The Sinn Féin leadership will continue to engage with the two governments and the rest of the parties. The onus however rests with the two governments and the British government in particular. We must see in the time ahead their plan to implement the Agreement in all its aspects."

Adams also confirmed that he is to meet with UUP leader David Trimble in the coming days.

Next six to eight weeks critical, says McGuinness

Speaking before travelling to London to meet British Prime Minister, Tony Blair, Mid-Ulster MP and Sinn Féin Chief Negotiator, Martin McGuinness, said that the next six to eight weeks will probably be the most critical period the north has seen in the last 30 years.

"It is crucial that politicians here adopt a positive agenda and collective approach over the coming months to end the political impasse," he said.

"I would caution that the political process is entering a critical time ahead of the Assembly elections in May and urge all parties to move forward together. The elections must go ahead; any suspension would effectively be a suspension of the democratic process and would be very damaging indeed.

"I think all of us at the heart of this process know the best way to go forward is to try and resolve our problems over the course of the coming six to eight weeks and to move forward together with a very positive agenda into those elections.

"Politicians here must develop a positive and constructive frame of mind. It's going to require, I think, a collective approach over the course of the next couple of months that I believe will be the most critical period that we have seen in the course of the last 30 years."

On Tuesday, the PUP annunced its withdrawal from the talks. Sinn Féin Assembly member Conor Murphy said that the standard of political leadership on offer from the main unionist parties had left the PUP with little other option.

"The political antics of the DUP and the UUP thus far in this process and the negative agenda they have adopted has left the PUP with little option but to withdraw at this time from the talks," said Murphy.

"It would be our intention to maintain contact with the PUP and would wish to see a situation where all of the unionist political representatives participated fully in the process.

"This is not a time for walking away or giving up. It is a critical time and it is a time for engagement and dialogue. That is the only basis upon which we can move forward collectively and see the Agreement implemented in full."

Earlier, in a New Year message, Sinn Féin National Chairperson, Mitchel McLaughlin, had called on the two governments and all the pro-Agreement Parties to renew their commitments to political progress.

"There is no acceptable alternative to making politics work," he said. "I call on all the pro-Agreement Parties to renew their commitments to the full and faithful implementation of the Agreement. Failure, for whatever reason, in implementing the Agreement only serves the agenda of those opposed to change and those wedded to violence.

"The ongoing violence in unionist areas of Belfast is testimony to how things deteriorate in the absence of political leadership. The two governments and the pro-Agreement parties must demonstrate the primacy of politics in order to renew hope in the community and society at large.

"To this end I urge all parties to engage seriously in the talks that will take place following the New Year break with a determination to have the political institutions re-established. It is only in the context of functioning political institutions that we can demonstrate that politics work and that there is no justification for continued violence."