Campaigning atheist Richard Dawkins has suggested that David Cameron does not believe in God in a leading article attacking faith schools.
The best-selling author of The God Delusion labelled Government policies supporting faith schools as "condescending" and "patronising" as they had been imposed by intelligent and educated people who had outgrown their faith.
"If you are like several government ministers - of all three parties - to whom I have spoken, you are not really a religious believer yourself," he wrote in the open letter to Mr Cameron published in the Christmas edition of the New Statesman.
"Several ministers and ex-ministers of education whom I have met, both Conservative and Labour, don't believe in God but, to quote the philosopher Daniel Dennett, they do "believe in belief".
"A depressingly large number of intelligent and educated people, despite having outgrown religious faith, still vaguely presume without thinking about it that religious faith is somehow "good" for other people, good for society, good for public order, good for instilling morals, good for the common people even if we chaps don't need it."
The evolutionary biologist, who guest edited the special double issue of the New Statesman, claimed the "most obvious and dangerous way" in which governments imposed religion on society was through faith schools.
He said the latest British Social Attitudes Survey had shown that religious affiliation, religious observance and religious attitudes to major social issues were now "largely irrelevant" to all but a minority of the population.
In an interview with the Evening Standard two years ago, Mr Cameron said his faith ran "hotter and colder by moments" and he did not feel he had a "direct line to God".
"If you are asking, do I drop to my knees and pray for guidance, no," he said.
"But do I have faith and is it important, yes. My own faith is there, it's not always the rock that perhaps it should be.
"I've a sort of fairly classic Church of England faith, a faith that grows hotter and colder by moments but... I suppose I sort of started life believing that one's individual faith was important, but actually the institutions of the church were less important.
"I do think that organised religion can get things wrong, but the Church of England and the other churches do play a very important role in society."
The open letter comes after the Archbishop of Canterbury Dr Rowan Williams received widespread publicity as a guest editor of the magazine earlier this year when he wrote that the coalition Government was pushing through radical change which no-one had voted for.Reuse content