THE threat to Christians in the Middle East is an "indescribable tragedy", the Prince of Wales said on Tuesday. He was speaking at the launch of a new report that concludes that Christians are the most persecuted religious group in a world in which religious freedom is in "serious decline".

This year's report on religious freedom in the world, by Aid to the Church in Need, covers October 2012 to June 2014. Compiled by journalists, academics and commentators, it warns that "religiously inspired terror is not only widespread but is on the increase". In 41 per cent of countries, religious freedom is either "impaired" or "in decline".

Change for the better was noted in only six countries. There had been a deterioration in 55 countries, more than one quarter (28 per cent) of the total.

In 14 of the 20 countries that showed high levels of persecution, this was linked to extremist Islam: Afghanistan, the Central African Republic, Egypt, Iran, Iraq, Libya, the Maldives, Nigeria, Pakistan, Saudi Arabia, Somalia, Sudan, Syria, and Yemen.

The report warns of the phenomenon of the "mono-confessional state", and the exodus of Christians from the Middle East. This is creating issues for the West, it suggests, as "religious hatred increasingly became a more obvious driving force for the growing refugee phenomenon."

Christians are vulnerable, the report argues, because they are "historically widely dispersed, often in cultures very different from their own". Christians in Syria numbered 1.2 million this summer, it suggests, down from 1.75 million in early 2011. The decline in Iraq had been "even steeper".

In a video message recorded for the launch of the report, Prince Charles said: "It is an indescribable tragedy that Christianity is now under such threat in the Middle East, an area where Christians have lived for 2000 years and across which Islam spread in AD 700, with people of different faiths living together peaceably for centuries."

In the face of "horrendous and heartbreaking" events, religious leaders had a responsibility to act, he said: "Rather than remaining silent, [they] have a responsibility to ensure that people within their own tradition respect people from other faith traditions."

He was able to address leaders of other faiths, he said, because "My own Christian faith has enabled me to speak to, and to listen to, people from other traditions, including Islam. . .

"It seems to me that our future as a free society, both here in Britain and throughout the world, depends on recognising the crucial role played by people of faith."

The report states that Muslim minority groups are also facing "terrible and systemic persecution. In most cases this is at the hands of other Muslims."

There are "worrying tendencies" in the West, the authors argue, including a "declining consensus on the rights of conscience of religious believers". Policy-makers are also guilty of "religious illiteracy . . . creating a formidable barrier of understanding between the West and other parts of the world".

Question of the week: Is religious diversity good for religious freedom?