The British and Irish prime ministers held crisis talks yesterday to salvage a deal to keep Northern Ireland's fragile power-sharing government in place.
Gordon Brown and Brian Cowen flew in unexpectedly on Monday to help rival Northern Irish parties Sinn Fein and the Democratic Unionist Party (DUP) overcome a dispute about when to transfer police and justice powers from London to Belfast.
Any failure to clinch a deal would be a major set-back to the Northern Ireland peace process, which ended three decades of violence and has been touted as a model around the world.
Northern Ireland First Minister Peter Robinson of the DUP said there had been some progress.
"I can't say there's going to be a deal. None of us can say that, but we're going to sit at the table until we get the deal," he told reporters.
Sinn Fein was guarded about the chance of agreement.
"It's too early to say what's shaping up," said Conor Murphy, Sinn Fein, member of the Northern Ireland Assembly and the Westminster Parliament.
Mr Brown has a particular stake in trying to ward off crisis.
He faces a parliamentary election this year and would not want his credibility and his Labour party's achievement as a co-signatory of the Northern Ireland peace deal in 1998 to be undermined.
Monday's discussions went on into the early hours and resumed yesterday with talks between Mr Brown and Mr Cowen followed by meetings with the predominantly Catholic Irish nationalist party Sinn Fein and the pro-British, mainly protestant DUP.
Downing Street did not say how long the talks could last, although it said Mr Brown had postponed until tomorrow a London cabinet meeting originally scheduled for yesterday.
The last-minute decision by the prime ministers to intervene personally implied the situation was close to breaking point.
Sinn Fein, which ultimately wants Northern Ireland to become part of the Republic of Ireland, demands the transfer of policing and justice powers take place as soon as possible and accuses the DUP of trying to put off the inevitable.
The DUP, which wants Northern Ireland to remain part of the United Kingdom, has denied the accusation.
In a reference to Sinn Fein demands for a firm deadline, Robinson said: "I fear no date... The date is not the important issue."
The most intractable problem, analysts said, is the parades commission, which oversees the province's Orange Order Protestant marches. The DUP wants this form of oversight over the tradition abolished. Sinn Fein, which sees the parades as provocative, wants the commission to remain.
"The very fact that so much emphasis is being put on the parading issue probably militates against the chance of an agreement," said Paul Bew, Professor of Politics at Queen's University Belfast.
"But let me make it crystal clear, this negotiation is not over and there is a possibility of a benign resolution but I would put it at possibility rather than probability."
The odds of a solution are improved by the probable reluctance of both sides to trigger the Northern Ireland Assembly election that would follow a break-down in talks.
Both parties would have seven days to find new leaders to work together, which would probably be impossible given the extent of any differences that proved insurmountable.
After that grace period, an election would be called.
The timing would be bad for the DUP, which is mired in a scandal involving Mr Robinson's wife that has forced him to temporarily stand aside as First Minister even though he is still overseeing the devolution talks.