Representatives of the Church of Scotland were also in attendance. From l-r, David Cameron with the Moderator of the General Assembly of the Church of Scotland, the Right Reverend Lorna Hood and Moderator Designate/Principal Clerk of the Church of Scotland the Reverend John Chalmers
Author Philip Pullman and philosopher AC Grayling are among the signatories of an open letter to David Cameron rejecting his recent assertion that Britain is a "Christian country".
The letter published in The Telegraph says that the claim is dangerous for society and suggests it is not an accurate reflection of Britain's multi-faith society.
The signatories say they respect the Prime Minister's right to his religious beliefs but "object to his characterisation of Britain as a 'Christian country' and the negative consequences for politics and society that this engenders".
"Apart from in the narrow constitutional sense that we continue to have an established Church, Britain is not a 'Christian country'," they say.
"At a social level, Britain has been shaped for the better by many pre-Christian, non-Christian, and post-Christian forces.
"We are a plural society with citizens with a range of perspectives, and we are a largely non-religious society.
"Constantly to claim otherwise fosters alienation and division in our society. Although it is right to recognise the contribution made by many Christians to social action, it is wrong to try to exceptionalise their contribution when it is equalled by British people of different beliefs."
They conclude by asserting that most British people "do not want religions or religious identities to be actively prioritised by their elected government".
Mr Cameron has previously spoken about his personal Christian faith, although he admits he is not a regular at Church of England services.
In the past he stated that, in contrast to the previous Labour government, his will "do God" but in a "limited and responsible way".
The most recent Census revealed a considerable drop in the number of British people describing themselves as Christian, down from 72 per cent in 2001, to 59 per cent in 2011.
Meanwhile the number of people saying they had no religion rose from 10 per cent to 25 per cent of the population.
The Church of England reported last month that its attendance figures had been stable over the last decade. In 2012 an average of 1.05 million people attended Church of England churches for a Sunday service, approximately the same as the figure for 2002.
