The legal right of parents to pull their children out of religious education should be removed, headteachers have said.

The National Association of Headteachers has passed a motion calling for a negotiation with the Department for Education over the legal framework which currently allows parents to remove their children from RE classes.

The national curriculum dictates that religious education be taught to all pupils, but parents can excuse their child from the lessons and pupils over the age of 18 can excuse themselves.

Headteachers this morning warned the allowance meant pupils were missing out on a “vital” part of their education, with parents able to pick and choose the religions studied by their child.

Hilary Alcock, headteacher of Buntingsdale Primary School and Nursery in Shropshire, said schools needed to show they “respect what is important to pupils and make RE and entitlement for all”.

“Parents may know their children best, but they may not always know what is best for them,” she said.

“What is best for them as they grow up in modern Britain may be outside of their own experience and their child’s primary socialisation.”

Tony Hegarty, a union representative from Liverpool, said some parents used the rules to get their children out of certain aspects of religious education.

He said: “It saddens me to say that sometimes parents only exercise the right to withdraw children from RE when the topics being studied are Hinduism, Judaism or Islam, and that I think is an extremely divisive mechanism.”

The motion was moved by Alcock in response to the government’s guidance on British values which, since last year, has required schools to demonstrate that pupils are “well prepared to respect others and contribute to wider society and life in Britain”.

This demand is one of several placed on schools by the government’s new prevent duty which came into effect last July and requires schools to take measures to identify radicalisation and extremism.

Sarah Hewitt-Clarkson, the headteacher of Anderton Park School in Birmingham, said that although she did not have a problem with parents routinely pulling pupils out of RE at her school, it was important for all pupils to have a well-rounded religious education.

“We are educators, and it would crush my soul to think a child could leave our schools without having been to an RE lesson.”

A government spokesperson said intolerance had no place in the classroom , hence why all schools are required to “actively promote fundamental British values so that pupils leave school with a tolerance and mutual respect of those of other cultures, faiths and beliefs”.

“Promoting British values should not be restricted to a single subject though and we will continue to respect the right of parents to withdraw their children from religious education if they choose,” he added.