British Prime Minister David Cameron has said that it could break with a European Union arms embargo on Syria to allow the flow of weapons to anti-government rebels battling Syrian President Bashar al-Assad.
"I hope that we can persuade our European partners, if and when a further change becomes necessary, they will agree with us," Cameron told a parliamentary committee on Tuesday.
"But if we can't, then it's not out of the question we might have to do things in our own way. It's possible," he added.
The arms embargo is part of a package of EU sanctions on Syria that currently roll over every three months, with the last extension achieved with the agreement of all 27 EU members on March 1.
Without unanimous agreement between all EU members to either renew or amend the ban in three months' time, the embargo becomes void.
Britain pushed for and won an agreement to amend the embargo to allow the supply of non-lethal equipment such as body armour and armoured vehicles to rebels, but warned that in future it might act alone.
Balance of power
Also on Tuesday, France hinted that it would push to get a European Union arms embargo on Syria lifted, saying the balance of power in the country had to change so President Bashar al-Assad understood he could not win by military force.
"France is thinking - although it is a European decision - of going further in lifting the embargo," Foreign Minister Laurent Fabius told a parliamentary committee.
"You will ask me is that not contradictory with finding a political solution, but we don't think so," he said.
"If we want President Bashar al Assad to shift then he must be made to understand that he cannot win through military force. There is a new balance of power that has to be created."
Fabius also said that Paris was working with Russia and the United States to create a list of Syrian officials that would be acceptable to begin negotiations with the Syrian opposition.
"We worked together on an idea... of a list of Syrian officials who would be acceptable to Syria's opposition National Coalition," he said.
Fabius said Syria's opposition chief Ahmed Moaz al-Khatib had said in a "very brazen manner" that he was willing to negotiate with some regime officials but not President Assad.
"We have discussed this with the Russians and the Amercans... There have been exchanges to seek a political solution," he said.