A year on from the UK government's promise of a resettlement scheme for Syrian refugees, just 90 have been offered asylum.

Some of Britain's top faith leaders are now urging David Cameron to do more to protect the most vulnerable, particularly in the face of a hash Syrian winter.

"Many refugees have experienced persecution, torture or sexual violence, sometimes because of their religion or ethnicity, or have disabilities or other urgent medical needs which make them particularly vulnerable. Some will not survive the winter," a letter signed by multiple religious leaders reads.

"We are proud of the way in which the UK has led the world in its humanitarian aid contribution to the Syria crisis. However, our help cannot end with aid. We urge you to show the same leadership on resettlement so that more of Syria's most vulnerable refugees can find sanctuary here in the UK.

"We welcomed the announcement, a year ago, of the Syrian Vulnerable Persons Relocation (VPR) scheme but we are disappointed that only 90 refugees have so far been offered a safe haven here in the UK via this route," the letter continues.

"One year on, we urge you to take this opportunity to commit to offering resettlement places to thousands, not hundreds, of refugees from Syria.

"In the face of a desperate and growing need, we believe that Great Britain has a moral responsibility to continue our noble tradition as a compassionate and welcoming safe haven for those in need of protection. As Prime Minister, you have the power to offer hope to people whose suffering is almost unimaginable to us. We ask you to do this today."

Signatures of the letter include the Archbishop of Wales Barry Morgan, Head of the Jewish Reform Movement Rabbi Laura Janner-Klausner and Assistant Secretary General of the Muslim Council of Britain Shaykh Ibrahim Mogra.

An estimated ten million people have been displaced by the ongoing conflict in Syria, four million of whom have fled the country since the outbreak of civil war almost four years ago. Over 1.25 million of these are children, and aid organisations working in the region have repeatedly expressed concern about both the immediate and long-term effects that the ongoing crisis will have on them. They are often described as a "lost generation".

Amnesty International is now calling on countries to increase their resettlement commitments to five per cent of Syria's refugees by the end of 2015, and a further five per cent next year. The UK has so far pledged to offer asylum to only a few hundred Syrians over the next three years.

"The UK government's relief efforts in the region are to be commended but it is clear that so much more needs to be done to protect people fleeing the Syrian conflict, including those at risk of persecution due to their religion or ethnicity," said Kate Allen, Amnesty International UK director.

"A year on from agreeing to resettle hundreds of refugees, the UK should take this opportunity to up their game and resettle thousands of Syria's most vulnerable. The UK has done this in response to other conflicts, what is stopping this government from doing the same?"

Refugee Council Chief Executive Maurice Wren has accused Cameron of failing those in need. "We promised them safety. We promised them hope. We promised them a future. If David Cameron fails to significantly increase the scale of Britain's resettlement scheme he will have broken that promise," Wren said.

Edie Freedman, Executive Director of The Jewish Council for Racial Equality added: "We in the Jewish community know only too well the perils of being refugees and the indifference which too often meets their desperate plight to find sanctuary.

Syrians now make up the largest refugee group in the world. We appreciate that this is not a job for Britain alone, but we must do our fair share."

The faith leaders join many others in calling on Cameron to do more. On Monday, a group of celebrities including Emma Thompson, Michael Palin and Sting signed a letter in which they said "every settlement place countries like Britain provide is a lifeline".

"Resettling 'several hundred people' just isn't good enough for a global leader. This issue isn't about migration statistics or party politics, it's about people. It's about the values that we in Britain hold dear; compassion and humanity," the letter contined.

"Your choice is simple, yet historic. You are in a position to offer some of the most vulnerable people in the world safety in Britain. You can offer hope. You can offer a future."