The Ulster Unionist leader, Mr David Trimble, has said there is little reason to expect a breakthrough in next week's intensive talks on the future of the North.
All the pro-agreement parties will travel to Shropshire for talks chaired by the Taoiseach and the British Prime Minister at the Weston Park House conference centre.
The structure of the negotiations has yet to be finalised, but it is believed it will be a mix of bilateral meetings and plenary sessions of all the parties.
Speaking after meetings with the Northern Secretary and other parties at Hillsborough yesterday, Mr Trimble said there was only one issue to be discussed in England: decommissioning. "The issue goes to the very heart of this process and threatens to destroy the process. We do hope there will be positive developments next week, but I do have to say just at this point one can't feel any degree of optimism about that," he said.
Sinn Fein's chief negotiator, Mr Martin McGuinness, rejected Mr Trimble's assertion that decommissioning was the only issue. "Poor David is living in a fantasy world. He will recognise when he reaches Shropshire next week that there is going to be a very, hopefully, comprehensive approach to how we resolve all of these matters," he said.
Referring to the recent loyalist killing of a Catholic man, Mr McGuinness said Mr Trimble "needs to realise that the focus should not be on the guns that are silent, but on the guns that are not silent."
He said the pro-agreement parties needed to work together and by doing so "defeat all the numbskulls who want to drag us into the past."
Mr John Hume of the SDLP warned the parties not to enter talks in a pessimistic frame of mind and called on all participants in the talks "to do what they have to do".
"We have to be positive, and it is very positive that the two governments and the two prime ministers and all the pro-agreement parties are going to be around the same table next week," he said.
It was originally envisaged that the talks would take place on Monday and Tuesday, break for the July 12th holiday on Wednesday and possibly reconvene on Saturday.
Government sources said yesterday they now intended the talks to conclude on Tuesday. "If we sent out signals that it could last for days, that's exactly what would happen," one source said.
The Northern Secretary, Dr John Reid, said the peace process had entered a critical phase and he hoped the structure of the talks would make it possible to "resurrect some of the vision that accompanied the original Good Friday agreement".
Speaking on the BBC, the DUP MP for East Londonderry, Mr Gregory Campbell, predicted that no successful deal could emerge from the talks. Any agreement had to have the support of both nationalists and unionists, "and we aren't going to have that if the DUP isn't there," he said, pointing to the party's gains in the Westminster and local elections.