Project leader Dr Jessica Deighton said: ‘We know schools have a strong commitment to supporting children’s mental health and well-being but have had little clear guidance about the best ways to approach this.

‘We want children and young people, parents and teachers to be confident that mental health in schools has an absolutely robust evidence base.’

The scheme will coincide with a new compulsory health education curriculum, which covers mental health. It comes amid fears of an epidemic of mental health problems among children and teenagers, fuelled by the internet. A recent study found loneliness among youths is on the rise due to increased use of social media.

Childwise, a market research company, found 58 per cent of nine to 16-year-olds sometimes felt lonely – up from 51 per cent last year. Its poll of 2,000 pupils found older girls were particularly affected, with 80 per cent of those aged 15-16 battling loneliness.

Research director Simon Leggett said: ‘They are spending time alone in their bedrooms, scrolling through digital content, watching the lives of others unfold … rather than going to a friend’s house.’