Probe into how youngsters could be encouraged to share fears over potentially dangerous behaviour of peers

Independent reviewer Nick Page this week concluded that no-one could have “predicted or pre-empted” the fatal stabbing of Ann Maguire by a 15-year-old pupil.

He said there were no warning signs known to staff or other agencies at the time.

But it has been revealed that murderer Will Cornick did threaten to kill the Scholes-born 61-year-old in a message posted on social media.

It was never flagged up to the authorities until it was too late.

Mrs Maguire was celebrating her 40th year teaching at Corpus Christi Catholic College in Leeds when she was stabbed during a Spanish lesson.

Cornick was later jailed for life for murder with a minimum of 20 years.

Her killing, in front of a class full of students, is the only time a teacher has been murdered by a pupil in a UK school.

The review said that Cornick had a happy childhood despite his “loving and supportive” parents’ splitting.

He had reported some difficulties when he started at the school but his head of year had commented that he was “a delightful pupil” and in Year 10, Mrs Maguire wrote: “William is a bright conscientious young man.”

But in December 2013, Cornick “communicated on social media to a friend about his hatred of Ann and talked about brutally killing her”, the report noted.

In February 2014, the report said, there was a dispute between Cornick and Mrs Maguire over a detention and, later, his parents said his relationship with the teacher had “broken down”. The report said this baffled Mrs Maguire.

But Cornick sent another message to a friend on Facebook that Mrs Maguire “deserves more than death, more than pain, torture and more than anything that we can understand”.

The report said Cornick had decided to murder her four days before he did so. He told other pupils about this and about plans to kill his current head of year and another teacher and her unborn baby.

Mr Page’s report read: “The police investigation highlighted that pupils had heard Will make such statements before and did not take them seriously. One pupil told police that Will had a dark sense of humour.”

It added: “The question ‘how can children be encouraged and supported to share concerns with trusted adults?’ goes beyond the scope of this review, but perhaps locally, through the Leeds Safeguarding Children Board, research can be undertaken on children and young people’s confidence and approach to disclosure of this type, and indeed this is likely to be a subject worthy of better understanding nationally.”