Lois Rogers

However, The Sunday Times can reveal that Bertrand simply moved to France after being released from prison, found work as a music teacher and once again preyed on a boy he taught.

In 2011, after leaving prison, Bertrand — who is on the UK sex offenders’ register and is barred from working with children — got a job as a teacher at the exclusive Victor Hugo School, one of the best-known international schools in Paris with fees of up to €24,000 (£21,100) a year.

He began grooming a 14-year-old boy, sending him explicit texts including many that said “I love you”. The boy’s father complained to the school, which dismissed Bertrand in 2013.

Yet in 2014 he had jointly set up a private school called Kingsworth International, also in Paris, where he is also a shareholder and became a deputy head.

Asked why Bertrand had been employed despite his conviction, Kingsworth’s head teacher, Stephen Jankowski, said the paedophile had “lied about his past”. Parents at the school, which is for pupils aged 3-18 and include many British families, were sent a letter saying the school had discovered Bertrand’s UK criminal record and dismissed him, but no details were given. Bertrand left the school last month.

Jankowski said Bertrand had passed the required background checks, adding that the welfare of the children is the school’s priority and that it acted immediately when it learnt of his previous conviction.

Sonia Notarianni, an American mother involved in the parent teachers’ association at Kingsworth primary school, said: “We were told there were parents who were very upset and have left the school because of this, but that was because he was apparently an amazing teacher. We [wrongly] understood that as a young man of 24 he had an affair with a 16-year-old girl or something.

“They have no checks on parents volunteering in the school or anything. When I volunteered to help out at my children’s old school in Florida, I had to have a full background search.”

Victor Hugo School’s president, Bernard DeleSalle, said he was horrified to discover “a devil” at his institution, and accused Bertrand of having “tricked” them. He said: “To discover a devil in the middle of angels is not easy, especially when he is well disguised. We are not infallible. Thank God, Bertrand is the only devil we have met.

“If he had gone into another school we would have found out and . . . ruined his plans, but because he created his own structure in direct competition to our establishment, we could not have publicly denigrated him without risking legal action.” The school said it had been unaware he had spent time in England.

References to Bertrand on Kingsworth’s Facebook site, which included details of his involvement in a skiing trip this year, have been removed.

France’s education ministry acknowledged a problem with identifying paedophile teachers. “A new law was put forward in 2016 to allow better communication between the justice and education departments, but it has not happened yet,” it said.

Bertrand could not be contacted at the address given as his home on the Kingsworth shareholder register, and the school refused to pass on a request for comment. He is free to teach elsewhere.

The head of the Somerset school at which Bertrand abused a pupil said: “As a citizen of this country as much as the head of a reasonably distinguished school, I find it extraordinary that the systems for safeguarding children do not appear to be joined up in a better way. It is very worrying indeed.”

On request, the Home Office can conduct criminal record checks for those who have lived in Britain and want to work with children overseas.