The prime minister Gordon Brown flew into Belfast last night for urgent talks with his Irish counterpart, Brian Cowen, to try to rescue Northern Ireland's power-sharing executive, as senior British government sources expressed deep unease at the Conservative approach to the political crisis in Ulster.
Brown believes the Conservatives are endangering the Northern Ireland peace process by adopting a pro-unionist stance in breach of the bipartisan approach which dates back nearly 20 years. He is attempting to broker a deal between Sinn Féin and the Democratic Unionist party to devolve policing and criminal justice powers to the Northern Ireland assembly.
He has told aides of his astonishment after the Tories convened talks among unionists at an English country estate.
Peter Robinson, the DUP leader, joined talks with senior figures from the rival Ulster Unionist party at Hatfield House in Hertfordshire, the country seat of the Cecil family, over the weekend of 16-17 January. The Marquis of Salisbury, the current head of the family, was the most pro-unionist member of John Major's cabinet.
The talks, convened by the shadow Northern Ireland secretary, Owen Paterson, prompted speculation in Northern Ireland that the Tories are attempting to establish a pan-unionist front to limit the success of Sinn Féin and the SDLP in the general election. The Tories have already formed a pact with the Ulster Unionist party to field joint candidates in Northern Ireland's 18 parliamentary seats.
A senior government source said: "We are simply astonished at what the Tories are doing. The Northern Ireland peace process has been strengthened by the bipartisan approach between all major parties at Westminster. Holding talks at a country estate and excluding the nationalists is absolutely not within that spirit."
The bipartisan approach dates back to November 1993, when it was revealed that Major's government had held secret talks with the IRA. John Hume, the former SDLP leader, marched into the office of the late Labour leader, John Smith, to ask him to pull his punches because an important political process was under way.
The Tories were strongly criticised in Northern Ireland last night. Alasdair McDonnell, the deputy leader of the SDLP, said: "This is a very sinister development. We have travelled far over 15 years of peacemaking and are now at the point of putting in the last piece of jigsaw. What we have is Mr Cameron parachuting in with hobnailed boots, going off into a corner with two parties and excluding three others."
Alistair Carmichael, the Liberal Democrat Northern Ireland spokesman, said: "How would Owen Paterson, if he were ever to be Northern Ireland secretary, possibly hope to command any confidence with the nationalist community? It is incredibly irresponsible."
The Tories said the Hatfield House talks had been blown out of proportion. Sources blamed Robinson for briefing that they were designed to establish a pan-unionist front. A Tory spokesman said: "This is yet another attempt by Gordon Brown to create an imaginary political dividing line. The meeting was a genuine and sensible attempt to help the peace process stay on track. We have consistently supported the government on Northern Ireland. Like the prime minister we want nothing more than to see policing and justice powers devolved to Northern Ireland and the situation there stabilised."
But nationalists are alarmed. The SDLP says it has sporadic contact with the Tories. Sinn Féin said Gerry Adams, its president, has never met Cameron. Martin McGuinness, the party's deputy first minister, has met Cameron once. Adams and McGuinness have both met Paterson.
The row came as the British and Irish prime ministers met the DUP and Sinn Féin at Hillsborough Castle, Co Down, last night. Brown, who postponed today's cabinet meeting until Thursday, flew with Cowen to Belfast after talks in Downing Streetat on the ongoing row between Sinn Féin and the DUP over the failure to transfer policing and justice powers.
McGuinness said he was "frustrated" by the lack of political progress after a lunchtime meeting with Robinson. Sinn Féin had earlier described the encounter between McGuinness and Robinson as "critical and defining".
Sinn Féin is under increasing pressure to pull out of the devolved government and bring the historic power sharing coalition down. It blames the DUP's obstinacy over policing and justice as the main cause for the crisis.
During a break in the negotiations, the Northern Ireland secretary, Shaun Woodward, said: "The prime minister and the Taoiseach met this afternoon in Downing Street and decided that the time was right to come to Belfast and engage in intensive talks with the party leaders, with Peter Robinson and with Martin McGuinness.
"Those talks are now under way, they will continue this evening and we expect them to continue into tomorrow.
"And we stand, both governments, ready to help the parties here in their talks on policing devolution and those remaining outstanding issues."
Micheál Martin , Ireland's foreign minister, said the governments were committed to finding an agreed way forward. "We are prepared to stay overnight to ensure we bring these talks to a conclusion and get the key issues agreed."
Sinn Fein junior minister Gerry Kelly briefly emerged from the talks to underline his party's demand for a swift transfer of law and order powers.
"We are here to do the business and we are here to talk about a date for policing and justice and that's what the discussions are about," he said. "I cannot go into detail..."
He revealed that while his party had held discussions with the two governments it had by 10pm yet to hold direct talks with the DUP in Hillsborough.
"We are here, we are talking, we do want to get this sorted out," he added.
DUP ministers Sammy Wilson and Arlene Foster stepped out of the castle to provide an update on negotiations and expressed hopes that a deal could be secured, though they were critical of what they described as the atmosphere of crisis that had developed.
Mr Wilson said: "As far as we are concerned this is a contrived crisis, we don't need to be here.
"There are many things I am sure most people would prefer that the Assembly would get on with the task which it already has competence over and secondly that the parties then would sit down in a responsible way and deal with the issues which are still outstanding to allow devolution of policing and justice to take place.
"That would have been a much better way to have dealt with this issue rather than the way in which Sinn Fein have tried to create this crisis here and of course the instability which is attached to that."
He insisted however that his party was committed to finding a resolution.