The rise of extremism has left Christians without hope for a future in the birthplace of their faith, according to a new petition to David Cameron, Nick Clegg and Ed Miliband.

Thousands of evangelicals who attended Spring Harvest are calling on the Conservative, LibDem and Labour leaders to set aside party differences and take new steps against persecution of Christians in the Middle East.

The 4,496 Christians warn that the faith is at serious risk of extinction in the region.

"Whatever the outcome in May, they are urging these leaders in the strongest terms to work across party and international lines to defend ethnic and religious diversity in the Middle East, which is crucial for the stability and prosperity of the region, said the charities Open Doors UK and Ireland, Bible Society and Spring Harvest.

A representative from Aleppo in Syria, whose name is not being disclosed for security reasons, told senior figures from all three parties about the work being done by the charities, the total devastation and the need for diversity if the region is to have a stable future.

Lord Feldman of the Conservative Party said the persecution was "terrible, shocking and catastrophic for the region, as Christians are a glue that holds the region together."

Rising Islamic extremism in the form of Islamic State and other groups has accelerated the exodus of Christians from the Middle East. In Iraq there are now fewer than 300,000 Christians left, compared to more than 1.2 million at the beginning of the 1990s. After IS swept through Mosul and Qaraqosh in 2014, an Open Doors field worker reported that "since 20 August until now [15 October], approximately 5,000 Christian families have emigrated."

The video showing the murder of up to 30 Ethiopian and Eritrean Christians in Libya by IS, coming soon after a similar video of the murder of 21 Coptic Egyptian Christians, has increased the fear that Christians have no future in the Middle East.

Many have decided to flee, some by taking the perilous journey across the Mediterranean in the over-crowded boat journeys that have already claimed the lives of more than 1,700 migrants since January 2015.

According to Open Doors, an international charity serving persecuted Christians in more than 50 countries, an estimated 100 million Christians worldwide suffer interrogation, arrest and even death for their faith in Christ, with millions more facing discrimination and alienation.