Faith schools must not be allowed to admit more children on the basis of religion, leaders have warned.

In a letter to the Daily Telegraph a group of 70 faith leaders, politicians and academics warned that lifting a cap which stops new faith schools admitting more than 50 per cent of children on the basis of religion would be "deleterious to social cohesion and respect".

The signatories, led by former Archbishop of Canterbury Dr Rowan Williams and Andrew Copson, chief executive of Humanists UK, warn that the policy, promised in the Conservative manifesto, "allows schools to label children at the start of their lives with certain beliefs and then divide them up on that basis".

"The Government rightly identifies the promotion of mutual understanding and tolerance for those of different religions and beliefs as one of the most important roles for schools. As we are all aware, children are blind to the differences and immune to the prejudices that so often divide society.

"The duty of the education system, therefore, should not be to highlight and entrench such differences in the eyes and minds of young people, but to emphasise instead the common values that we all share.

"Removing the 50 per cent cap on religious selection at faith-based free schools runs entirely counter to this ambition," the letter, also signed by Caroline Lucas, co-leader of the Green Party, Professor Richard Dawkins and Baroness Joan Bakewell says.