The new package, launched by the National College for School Leadership, was created in response to the Bichard inquiry into the murder of Soham schoolgirls Holly Wells and Jessica Chapman in August 2002.

The girls were murdered by Ian Huntley, caretaker of the town’s secondary school, who had moved to Soham under a new identity. His references were suspect, and police checks failed to reveal key details of his past.

The inquiry last June recommended that school interview panels should contain at least one member trained in appointing people to work with children.

The online training is free for all headteachers and for one nominated governor from every state school in England. It gives best practice suggestions and practical advice. The training covers every stage of the recruitment process, including person specification, job description, advert, interview, pre-appointment checks, induction, probationary period and further “in-post” monitoring.

At St Helen’s primary in Bluntisham, Cambridgeshire, headteacher Wendy Harknett has urged other heads to follow her example and do the training.

“Headteachers should do this at once before they embark on any new recruitment,” she said. “We’ve always prided ourselves on being up-to-date on everything in our school but I got a lot of additional information from this package, particularly on getting the right message across in recruitment ads and the sort of follow up questions to use in interviews.”

The training course takes around five hours to complete. But it does not have to be done in one session.

Mrs Harknett used it almost immediately. “I was recruiting a new caretaker; we asked a lot more questions related to safeguarding children and I added supplementary questions into the referee request,” she said.

“It became obvious that I needed to raise his awareness about the child-protection responsibility the role involved - he might find a child in the toilets crying or bruised, or a pupil could develop a crush on him.

I spent a lot of time going through this at the induction stage. I wouldn’t have done that in such depth before doing the training.”

The training includes a “How much do you know?” quiz, and multiple-choice questions at the end of each module test the candidate’s understanding.

After a final assessment successful applicants get a certificate.

The training is not mandatory, but the NCSL strongly recommends all heads do it and work with governing bodies to identify a governor to do it too.

It also offers advice on creating a safer school culture and open environment where staff can raise concerns.