A report out today has raised questions about the quality of Religious Education teaching in schools.
The All Party Parliamentary Group on RE looked at teaching of the subject in over 300 primary schools.
The inquiry found that over half of those teaching RE lessons had no qualification or relevant expertise in the subject.
In a quarter of primary schools, RE lessons were being led by teaching assistants who had received little support, training or guidance.
Primary school teachers were found lack of confidence and expertise in teaching RE, particularly those in charge of culturally diverse classrooms.
Cuts to local authority funding and the Government's academies programme have resulted in support for RE teachers being "dramatically" reduced, the MPs warned.
The end of bursaries for RE trainees has seen a "radical" reduction in applicant numbers to teach the subject.
At the same time, the report warned that the lack of training and support has meant that many RE teachers are falling short of the Department for Education's teaching standards.
The Reverend Jan Ainsworth, the Church of England's chief education officer, said the report should be a "wake-up call" for Education Secretary Michael Gove.
"RE is about religious literacy for all, growing understanding of the importance of faith, especially in this country, built on Christian values, to the lives of individuals and communities. It is has never been more important than in today's multi-faith society," she said.
Stephen Lloyd, chair of the group behind the report, said: "It is illogical to think that we can dilute the professionalism and expertise needed to teach RE well and still have a generation of young people that understand and are sensitive to the growing levels of religious and non-religious diversity in our society."