International talks on Syria taking place at the United Nations in New York could lead to the tabling of a Security Council resolution on the transition to a new government in the Middle Eastern state by the end of the day.
Speaking to MPs earlier this week, Foreign Secretary Philip Hammond held out the possibility that the meeting of the International Syria Support Group (ISSG) could produce a text for the council which will not be vetoed by Russia.
The talks come a day after security council finance ministers, including Chancellor George Osborne, agreed a resolution to step up efforts to cut off all sources of funding for the Islamic State (IS) terror group - also known as Isil, Isis or Daesh - in Syria and Iraq.
Hailing the agreement as a "historic moment ... to cut off Daesh financing", Mr Osborne said: "We'll choke off Daesh trade in oil, end extortion, stop sales of historic artefacts and take the fight to middlemen who trade in currency of evil.
"The message from UN to Daesh is clear - the buck stops here."
Hopes of a second resolution were boosted when Russian president Vladimir Putin said on Thursday that he backed a draft being circulated by US secretary of state John Kerry.
Russian support for Bashar Assad has been the main obstacle to international unity over Syria, with Mr Putin insisting that the current president - a long-standing protege of Moscow - should be allowed to stand in an election to choose the post-war administration.
He repeated on Thursday that it should be for the Syrian people to determine their leadership.
Mr Hammond, who is representing Britain in New York, said that progress could depend on Russia assessing that the protection of Assad is not a "strategic objective".
Britain remains insistent that Assad can remain in place temporarily as part of a transitional administration, but cannot have a long-term role in government.
Speaking to the Wall Street Journal, the Foreign Secretary acknowledged that the debate about Assad's future had not shifted "at all", despite the gathering pace of diplomatic efforts, which saw the ISSG agree in Vienna last month a six-month timetable for the establishment of a transitional government.
"There are reasons for optimism but, every now and then, we have to pinch ourselves and remind ourselves that there is still this huge question that divides us around the table over the future of Assad," Mr Hammond said.
"I think that is possible that a role that didn't give (Assad) control of security apparatus might be acceptable to probably a large proportion of the opposition during a transitional period, but still not a long-term presence."
Mr Hammond told MPs on Wednesday that the meeting was being held in New York rather than Vienna "specifically to be able to go immediately to the United Nations Security Council if it becomes clear during the morning that it is possible to reach an agreement that the Russians will not veto in the UN Security Council.
"So there is a possibility - I put it no higher than that - that Friday's meeting will end with a UN Security Council resolution."
The Foreign Secretary met counterparts from ISSG states the US, France, Germany, Saudi Arabia and Turkey in Paris on Monday, and said that it was the "clear intention" of Mr Kerry to seek agreement in New York on a ceasefire deal for Syria.
"Frankly, that will be highly challenging, but I commend him for his ambition," he said.
The UK - which has been conducting air strikes against IS following a high-stakes Commons vote earlier this month - hopes that a move to a transitional government could allow non-extremist elements in Syria to join forces in turning their fire on IS.
Recent talks in Saudi Arabia brought together Sunni rebel organisations with a view to establishing a representative group that could negotiate with the Assad regime in talks due to start in January.
Mr Hammond aknowledged that the process would be "messy", but said it was important to "use all the forces available to support the integrity of the Syrian state and drive out Daesh".
The Foreign Secretary told the WSJ that Britain would use the New York talks to push for confidence-building measures to maintain the momentum of the process, such as commitments from all sides to facilitate humanitarian access and stop attacks on civilian populations and medical centres.
"These kinds of measures are short of a ceasefire but certainly start to put into place the kind of mechanics on the ground that could lead in time to a broader ceasefire," he said.