More than half of schools have failed to follow government guidance on staff recruitment aimed at preventing a repeat of the Soham murders, The TES has learnt, prompting tough new rules forcing them to comply.
Heads and governors have had more than four years to complete a free training course, showing how to avoid appointing paedophiles and other child abusers to jobs in schools.
The Department for Children, Schools and Families recommended that two people from every school participated. But only 40 per cent of schools have done so, leading the Government to draw up regulations to make the training a legal requirement.
Children's charity the NSPCC is calling on all heads to take the course. But a heads' leader has accused the Government of teaching them "how to suck eggs".
Extra training for heads and governors was recommended in 2004 by the Bichard Inquiry, set up after 10-year-olds Holly Wells and Jessica Chapman were murdered by Ian Huntley, appointed school caretaker at Soham Village College despite a string of sex offence allegations.
The resulting online course run by the National College for School Leadership has been available since April 2005. It includes training on characteristics of child abusers and their behaviour, how to spot them in interviews and how to create a safer culture for children in schools.
The NCSL said it was designed to be flexible, "accessible from anywhere at anytime", with an "understanding of the heavy demands on the time of key people in a school". The four-to-five hour course can be taken from any computer over any number of sessions of any length.
But DCSF research in December showed that in 26 per cent of schools no one had taken the training, and that in another 34 per cent only one person had been on the course.
A DCSF spokeswoman said: "Given the fact that schools have had four years to complete this training and quite a lot still have not done so, we think it should become mandatory."
The Government is consulting on a regulation that states that from 2010 every school staff interview panel should contain at least one member who has completed the training.
Mick Brookes, National Association of Head Teachers general secretary, said "there are too many people spending money on courses teaching my members how to suck eggs".
"People may have already looked at the safer recruitment training and thought, `We already know and do these things and therefore why do we need this training?'.
"Most schools have very sophisticated recruitment procedures."
But an NSPCC spokesperson said: "We would like all headteachers to go on this scheme and hope that in future it will include refresher courses."
The issue of safe recruitment was recently highlighted at Canonbury Primary, where London Mayor Boris Johnson and former schools minister Lord Adonis both send their children.
A majority of governors at the school in Islington, London, resigned in April after claims that teachers appointed to the school had not been properly vetted.
Jay Henderson was sacked as head last month following claims he was caught viewing internet pornography at work.
Yesterday, former Canonbury teacher Robert Stringer was due to appear before magistrates accused of raping and sexually assaulting a young girl.
The allegations relate to a period before he worked at Canonbury.