Lord Carey, the former Archbishop of Canterbury, led criticism aimed at the Government for failing to provide a safe haven to Christians trying to flee the Islamic State of Iraq and the Levant (Isil).
He will sign a petition that is being launched on Monday calling on the Government to “welcome Christian refugees and give them priority as asylum seekers”.
It comes amid growing concern that the Government is ignoring their plight.
Last week, 42 Christian families were smuggled out of Syria to Beirut and then flown to Poland where they received safe haven. The operation was run by the Barnabas Fund, a charity aiding persecuted Christians, and the Weidenfeld Safe Havens Fund, a Jewish-funded organisation founded by Lord Weidenfeld, the publisher.
More Christians will be evacuated to the Czech Republic and even as far away as Brazil in coming weeks but, according to the organisers, the Government has so far refused requests to relocate Christians in the UK. Lord Carey said last night: “Syrian and Iraqi Christians are being butchered, tortured and enslaved.
“We need the British Government to work with charities like the Barnabas Fund and others to evacuate those who are in desperate fear of their lives.”
Lord Weidenfeld, 95, who fled Nazi-occupied Austria in 1938 with the help of British Quakers, said: “Why is it that the Poles and the Czechs are taking in Christian families and yet the British government stands idly by?
“This mood of indifference is reminiscent of the worst phases of appeasement, and may have catastrophic consequences. Europe must awake and the Conservative British Government should be leading from the front.
"Most European governments, especially those that are Christian explicitly or implicitly, are failing in their duty to look after their fellow Christians in their hour of need.”
The petition, launched by the Barnabas Fund, calls on governments to work with Middle East countries and “recognise that Christians are especially targeted and uniquely in need of safe refuge”.
The petition points out that the Christian communities in Syria and in Iraq are among the oldest in the world but that they now face “an existential threat to their survival”.
It adds: “They are being killed, enslaved and persecuted by so-called Islamic State and are forced to flee from their homes. Their homes are being destroyed and they have no safe areas in the region.
“The oppression and persecution of Christians, simply for their faith, is leading many Christians to conclude that they have no choice but to leave.”
The Barnabas Fund claims that just over ten years, the numbers of Christians living in Iraq has plunged from 1.5 million to 300,000 while in Syria it is estimated half a million Christians, out of two million, have fled since the beginning of the current conflict.
Dr Patrick Sookhdeo, the Barnabas Fund’s international director, said: “With the rise of Islamic State we are seeing what looks set to become a 'genocide’ of Christians in the Middle East, yet the UK has its doors firmly closed.
“So many British Christians have been in contact with us to tell us that they have a spare room or even a second home in which they want to welcome Syrian and Iraqi Christians. Yet our government seems determined to turn its back on some of the most vulnerable people in the world.”
Canon Andrew White, the former vicar of the only Anglican church in Iraq, said: “I really think it is horrendous that the British have not offered refuge to these Christian refugees.”
The Most Rev Justin Welby, the present Archbishop of Canterbury, has expressed his concern over the plight of Christians in Syria and Iraq and has “offered his full support for them being given protection in the UK and in other Western countries”.
David Cameron drew criticism from charities and aid organisations in June after announcing he would “modestly expand” the number of Syrian refugees allowed into the UK by offering “a few hundred more” places.
The Government has declined to show a preference for Christian refugees. It was reported in June that Britain granted entry to 187 Syrians since Theresa May introduced the Vulnerable Persons Relocation scheme in January 2014.
The Prime Minister said the UK would boost the number of places to resettle the most vulnerable, but Downing Street said the figure would not exceed 1,000.
By comparison, Germany has offered 30,000 places to resettle Syrians, Sweden has committed to resettling 2,700, Switzerland has offered 3,500 places and Austria 1,500.
A source close to the Barnabas Fund said: “The UK government are blocking our evacuations. We are negotiating with governments in eastern Europe and even as far afield as Brazil but the British government is so far not forthcoming.”