In nearly every country where Islam coexists with Christianity (in fact, with any other religion), this story is repeated: ‘Leave, crusaders, or have your heads cut off’. (Hat tip: Amy.)

The snow has already settled on the mountains further north, but the Christians of the Iraqi city of Mosul are scared to put festive decorations outside their homes this year. Their ancestors settled here in the 1st century AD, yet as teacher Jamal Fadi has discovered, some of their Muslim neighbours want this Christmas to be their last.

“A letter was delivered to my door with two bullets placed on top of it,” said Mr Fadi, 32, standing watchfully in the neat garden of his two-storey villa. “It said: ‘Leave, crusaders, or we will cut your heads off.’ They want us to go from Mosul completely.”

After months as a nervous bystander to the spiralling civil war between Sunni and Shia Muslims, Iraq’s Christian minority now faces the spectre of sectarian violence coming to their traditional home city. They fear that al Qaeda-backed zealots within the Sunni community, which forms the bulk of Mosul’s one million population, want to end nearly 1,500 years of co-existence with an onslaught of ethnic cleansing.

Residents say that the campaign, which they claim has intensified in recent weeks, is prompted by Sunni fears of a complete Shia takeover of Baghdad in coming years. In response, Mosul would be turned into a northern capital for a Sunni-dominated enclave, which would include Saddam Hussein’s home town of Tikrit and stretch south to the anti-American towns of Fallujah and Ramadi.

The fact that no such blueprint has been endorsed by the Iraqi government is of little comfort to Christians. The plan’s architects, they fear, are capable of enforcing it themselves through threats and indoctrination alone. For proof, they say, look no further than playgrounds, where Christian and Sunni Muslim children have played together for decades.

“Our children are told by other pupils that they are ‘f***ing spies’ who have brought the Christian occupation to Iraq,” said Father Shamoun Butris, a Christian minister in Mosul. “It is not true, but makes no -difference.”