After a day of chaotic negotiations at the UN, the US state department predicted that support for the US-British-Spanish resolution setting an ultimatum for Saddam Hussein and a series of disarmament tests was firming up.
The state department insisted it had four votes in the bag: the three African countries - Angola, Cameroon and Guinea - and Pakistan.
Despite earlier statements from Islamabad that Pakistan would abstain in a security council vote, the state department was apparently confident of a last-minute yes vote from Pakistan after a conversation between President Bush and President Pervez Musharraf.
It added that it remained hopeful of securing the votes of either Mexico or Chile or both.
But the Foreign Office assessment was much more pessimistic, and surprise was expressed that the state department was being so upbeat.
The Foreign Office said that there was no sign of either Mexico or Chile voting for the resolution, and none of the African countries nor Pakistan was aboard.
Compromises offered by Britain, such as more time for Iraq to disarm and a series of six tests for PresidentSaddam, had failed to win them over.
A British official blamed the French president, Jacques Chirac. The British position is that Mexico and Chile both face hostile domestic opinion and they feel there is no point incurring public wrath in order to support a resolution that will be lost because of France's veto.
The timing of a vote on the resolution has been thrown into disarray and Spain even indicated it might not take place at all because of the threatened French veto.
The US and Britain said yesterday the vote would have to be held before the end of the week.
Tony Blair and the foreign secretary, Jack Straw, continued last night to phone the leaders and foreign ministers from the six countries.
A Foreign Office source said yesterday: "It depends on what happens overnight. It does not look too good just now. That might change and it might look different in the morning if one of the countries signalled agreement."
At a press conference in London, Mr Straw said the process was "now coming to a conclusion which will have to happen before the end of this week".
He added: "We have been working flat out for agreement on a second resolution."
Despite the disparity between the optimistic view taken by the US and the pessimistic Foreign Office picture, both sides are agreed on one thing: Chile and Mexico are proving the hardest to persuade.
Chile's president, Ricardo Lagos, has described his country's position as being "equidistant" from the US and French positions, arguing that Iraq's disarmament would take several months.
However, Chile is counting economically on a free trade agreement that is currently before Congress for ratification, which Chilean commentators have warned could be in doubt if it defies Washington.
However, Mr Lagos, the first socialist leader Chile has had since Salvador Allende was overthrown in 1973 with US connivance, said the two issues were not connected.
"The free trade treaty is not a present that the US is giving to Chile or that Chile is giving to the US," the president said. "It has been done because it is to the benefit of both countries. To link these two things is profoundly mistaken."
Meanwhile, the US ambassador to Mexico has warned that legislation to further liberalise trade or to legalise millions of undocumented Mexican workers in the US might be hindered in Congress if Mexico does not support Washington on Iraq.
But President Vicente Fox is reported to feel let down by President Bush who had agreed to support amnesties for illegal Mexican immigrants, but who dropped the plan after the September 11 attacks.
The White House spokesman, Ari Fleischer, yesterday insisted that the US was still involved in UN talks mainly to placate Britain and Washington's other supporters.
An administration official said yesterday that he expected the "dynamics" of the security council debate to change once the resolution was put to a vote and the 15 member states were forced to decide.