Church of England bishops say the government has a "moral duty" to grant Iraqi Christians asylum in the UK, as the militant threat from the Islamic State (IS – formally the Islamic State of Iraq and Syria: ISIS) worsens in Iraq.

Tens of thousands of Christian refugees have fled the Iraq city of Mosul – one of the world's oldest Christian communities – after IS forces overran the area in June and threaten to kill Christians who did not convert to Islam.

On Saturday, about 70,000 Shiite refugees from Mosul and neighbouring regions were flown out of Erbil to Baghdad, and other cities like Karbala and Najaf in Southern Iraq, in a joint operation led by the Erbil governorate and UNAMI (UN Assisted Mission for Iraq) and UNHCR (UN High Commissioner for Refugees).

Now representatives from the Church of England are calling on the UK government to help displaced Iraqi Christian, especially in light of Britain's role in the 2003 Iraq invasion, which caused years of instability and led to the rise of Islamic insurgents.

Speaking to The Observer, the Bishop of Manchester, the Rt Rev David Walker, said: "We would be failing to fulfil our obligations were we not to offer sanctuary. Having intervened so recently and extensively in Iraq, we have, even more than other countries, a moral duty in the UK.

"Given the vast amounts of money that we spent on the war in Iraq, the tiny cost of bringing some people fleeing for their lives to this country and allowing them to settle – and who, in due course, would be an asset to our society – would seem to be minuscule."

iraq crisis
Lying face down in the dirt, prisoners in Iraq are executed by a small band of jihadists.

Bishop of Leeds, the Right Reverend Nick Baines, said: "The Government cannot remain silent and you cannot just issue words – you've got to put something behind that.

"If we can't offer sanctuary to these people, then who will? Not doing so would be tantamount to the betrayal of our moral and historical obligations."

The appeal to the UK government comes as Andrew White, vicar of St George's Church in Iraq – affectionately known as the Vicar of Bagdad, faces mounting pressure to leave the country due to threat posed by the Islamic State, which is responsible for killing more than 200 members of his congregation.

Writing on Facebook at the weekend, he described the horrific death of a family while at home reading their bible.

"You know I love to show photos but the photo I was sent today was the most awful I have ever seen. A family of 8 all shot through the face laying in a pool of blood with their Bible open on the couch. They would not convert it cost them there life. I thought of asking if anybody wanted to see the picture but it is just too awful to show to anybody. This is Iraq today. The only hope and consolation is that all these dear people are now all with Yesua in Glory."

Over the last five years he has lost 1,096 of his parishoners because of the rise in sectarian violence in Iraq.

It is believed around 800,000 Iraqi internally displaced people are currently based in the Kurdistan region, with the majority of them from Mosul, Anbar and Fallujah.