Thousands of schools will shun a new national framework for religious education, church leaders said this week. They fear schools will continue to run locally-agreed syllabuses unless the voluntary RE code is made compulsory.
Charles Clarke, the Education Secretary, is expected to unveil the guidance in coming weeks.
RE is an entitlement of every pupil but is not in the national curriculum.
Local authority advisers and church school governors create their own syllabus.
Early outlines of the new framework prepared by the Qualifications and Curriculum Authority referred to minority religions, such as the Baha'i faith, Jainism and Zoroastrianism. They also said Christianity should be taught at each key stage and that other principal religions - Buddhism, Hinduism, Islam, Judaism and Sikhism - should be taught by the age of 16.
The document has been widely welcomed by advisers, subject experts and church leaders, but it is feared there may be a reluctance to deviate from local syllabuses.
Peter Shepherd, of the Association of Anglican Secondary Heads, said: "RE ought to be added to the national curriculum - I cannot imagine if this framework is non-statutory that it will have any effect. I am in favour of a national system that will give RE more clout, but it seems to me they have failed to grasp the nettle."
Robert Jackson, professor of education at Warwick university, said: "This is going to be a very influential document and has been greatly welcomed.
The tension remains that it is a halfway house. I think eventually RE should be a national curriculum subject."
Father Joseph Quigley, the Roman Catholic church's RE adviser for 11 to 19, said its schools would continue to respond to the Catholic curriculum directory, published by the bishops in 1999.
Sarah Smalley, chairman of the Association of RE Inspectors, Advisers and Consultants, said the draft guidance had already been taken up by at least one council but that it would be impossible to gauge its true impact until the final document was released.
The Office for Standards in Education confirmed it would not be using the framework to guide inspection of schools' RE provision and that it will continue to rely on a "locally agreed syllabus".
The QCA is completing the final draft of the framework, which will then be approved by Mr Clarke and distributed to councils.
The early document, released in April, was attacked by the National Secular Society for failing to encourage critical analysis of religion and sidelining atheism. But in a letter to Nottingham North MP Graham Allen - a supporter of the society - Mr Clarke said the final version "will incorporate" some of its views.
Marilyn Mason, education officer at the British Humanist Association, said:
"From the draft, the framework seemed quite broad, balanced and good for RE generally. Teachers, it seemed, really liked it but RE advisers did not because it could mean they have fewer responsibilities. That's why I hope it will become statutory."
A DfES spokesman said no decision had been made about adding the framework to the national curriculum but insisted RE "must be studied and is as important as other subjects".