Britain announced it would double support to Syria's fractured opposition forces yesterday amid reports that almost the entire 50,000-strong Christian population of Homs had been driven out by fighting.
William Hague, the British Foreign Secretary, told the Lord Mayor's Easter banquet in the City that pounds 500,000 would be set aside to provide non-lethal assistance to opponents of the Assad regime.
Britain has already provided pounds 450,000 to the opposition since last year, but the new funds will be used to extend the scope of support to include satellite communications equipment, training schemes and back office facilities for the opposition.
The scale of violence has reached an unrivalled peak in Homs, where the number of Christians left in the ancient city has fallen below 1,000.
As a major government offensive against Baba Amr and other rebel-held areas of Homs got under way in early February, many Christians left because of the intensity of the fighting.
One priest from the district of Hamidiya, who fled to Lebanon seven weeks ago, said friends who remained in the city had spoken of a growing "atmosphere of fear". "Some Christians who tried to escape a week ago were stopped from leaving by the rebels and were instead forced to go to a mosque to act as shields," he said. "They thought that, because Christians support Assad, the government would not attack them."
Church leaders have accused Muslim neighbours of turning on the Christians.
"The people we are helping are very afraid," Bishop Antoine Audo of Aleppo said. "The Christians don't know what their future will hold. They are afraid they will not get their homes back."
However Abou Salaam, a Jesuit priest in the city, said that Muslim imams had held meetings with the remaining Christians to reassure them they were safe.
Despite the broad public respect they enjoy from the rebel leaders, many Christians fear that they will remain vulnerable. About one in 10 of Syria's 20 million population is Christian.
"There were rumours of extremists coming to Homs from other Muslim countries to fight with the rebels," he said. "We don't know if it was true, but it frightened many people."
He added, "The Christians are caught in the middle. We are victims of both sides."
Efforts to stop Syria's descent into civil war reached a decisive juncture with the launch of a peace initiative by Kofi Annan, the joint UN and Arab League envoy on Syria. The plan has the support of Russia and China, as well as the West and the Arab League.
Officials said that the opposition needed to come together as a viable opponent and a potential alternative centre of power to President Assad, if, as hoped, he is eased out of power. "President Assad and his allies... must be left in no doubt that if there is not a political transition that reflects the will of the people, then they will be shunned by the international community and we will close every door to them," said Hague.
"They will face still more sanctions. Their assets will remain frozen. Their travel to Europe and many other nations will always be banned, as will the travel of their families. And they will be pursued by mechanisms of justice and held to account."
With at least 26 killed in continuing government offensives two days after the Syrian leader accepted Mr Annan's proposals, Assad set out conditions of his own for a ceasefire.
The Annan plan must also get a commitment from armed groups to cease their "terrorist acts" against the government, the state news agency reported yesterday. Julien Dacey-Barnes, a Syrian analyst at the European Council for Foreign Relations, said champions of the Syrian opposition had been forced to accept that diplomatic efforts to oust Assad would prevail over military options.
"The Annan plan is the only game in town for the moment," he said. "Outside intervention is impossible for diplomacy is the only way forward. Therefore there is a need to build a stronger opposition to take part in the political process."