DUP officers were meeting in Belfast late last night amid growing British government concern as to whether the Rev Ian Paisley will deliver his party in time to meet Monday's devolution deadline.
The extent of those concerns became clear after another day of intensive negotiations, during which chancellor Gordon Brown's latest £1 billion package - and a promised review of differentials in corporation tax rates between Northern Ireland and the Republic - apparently failed to clinch agreement on the appointment of a new powersharing executive on March 26th.
In a further sign of tension within the DUP, Gregory Campbell MP said he believed the deadline stipulated by the British and Irish governments could not be met. And British pressure was said to be building on deputy leader Peter Robinson amid fears that Dr Paisley could lack key allies at tomorrow's scheduled meeting of the party's executive.
Senior British sources made clear last night they were satisfied Dr Paisley wants to meet the deadline and assume the office of first minister at Stormont on Monday. And prime minister Tony Blair was still banking on the exercise of Dr Paisley's authority to overrule those prioritising concerns about party unity in favour of delaying the start of devolved government until some time in May.
As Dr Paisley and Mr Robinson flew back to Belfast, Downing Street's expectation was that the DUP officers would meet again today and that no final decision was likely to be communicated to Mr Blair before tomorrow evening.
However, Mr Campbell told The Irish Times he believed the situation, and the party's intentions, would probably be clearer as a result of last night's meeting of the officers. Mr Campbell also confirmed his view that Sinn Féin's "conditional" backing for the Police Service of Northern Ireland meant the "testing period" of republican bona fides demanded by the DUP executive had not even begun.
"In my opinion Monday is simply not do-able," the East Derry MP said.
Other senior DUP sources meanwhile agreed that Mr Robinson would play a pivotal role in the party's decision-making process in the next 24 hours, amid clear evidence that Mr Blair had not convinced key doubters that failure to achieve devolution on Monday would result in dissolution and spell the end of the process for some time.
At his meeting with the DUP delegation on Wednesday Mr Blair told Mr Robinson and fellow MP Nigel Dodds that he would not introduce emergency legislation to shift the deadline or extend the life of the Assembly.
However, it is understood both men equally directly questioned whether the prime minister would really "walk away from his legacy" for the sake of a two-month delay.
The Irish Times understands that, when pressed, Mr Robinson indicated he would back Dr Paisley if he decided to go ahead and form an executive on Monday - while warning Mr Blair this "could be at a cost" in terms of DUP unity.
There were also unconfirmed reports yesterday of some differences in the approach of Dr Paisley and Mr Robinson on the question of "transitional" arrangements that might carry the party through an interim period between the nomination of ministers and the formal start of devolved government.
Northern Secretary Peter Hain made clear such an arrangement would have to be within the existing legislative framework. However, Mr Robinson was said to be holding out for new legislation which would see an executive appointed but then effectively "frozen" or existing in "shadow" form until May.