The Church of England has refuted claims that virtually all faith schools in England are breaking the law.

The allegation was made in a report published today which claims that faith schools are illegally denying places to significant numbers of children. The British Humanist Association (BHA), which campaigns against faith schools, said the research uncovered extensive violations of the School Admissions Code.

"It's well known that religious schools have been abusing the admissions system for some time," BHA chief executive, Andrew Copson, said.

"Even so, no one can have imagined the problem was as widespread as this report shows."

However the Church of England has denied the allegations and criticised the report.

"We would strongly refute any suggestion that our schools have a near universal non-compliance with the Code," said the Church of England's chief education officer, Nigel Genders.

"The Office of schools adjudicator annual report tells a very different story to this over exaggerated report which equates small administrative errors or minuscule technicalities with major systemic failure.

"If schools were able to focus more time on getting on running their schools, rather than responding to these sorts of campaigns, children would be better served."

A quarter of the schools investigated were found to be selecting on religious grounds in ways deemed unacceptable even by their own religious authorities, according to the Guardian.

However, Genders countered this by saying the majority of Church of England schools do not select pupils on a faith basis.

"The majority of Church of England schools do not prioritise their places on the basis of church attendance, and most of those that do still make places available for children in the school's immediate community," he said.

"Our secondary schools have an average of 10 per cent selection by religious criteria – this is based on church attendance only."

The study, compiled by the BHA for the Fair Admissions Campaign, looked at the admissions policies of 70 secondary faith schools out of a total of 535 in England.