The Association of Teachers and Lecturers (ATL) survey of 850 education professionals found nine out of 10 schools or colleges have had to provide more support to pupils with mental health problems over the last two years.
Half of those surveyed said they had seen an increase in the number of children in their school with mental health issues and 43 per cent laid the blame for this on cuts to CAMHS services, which they said pupils are struggling to access.
Among those surveyed only five per cent believed access to CAMHS had become easier for young people to access over the last two years.
One secondary school head of department told the ATL that CAMHS is "completely overwhelmed".
"Unless there is significant risk of harm to either the child or others there is pretty much no point contacting them,” the unnamed head of department said.
An increase in time and resources to support this vulnerable group in schools was called for by 59 per cent of those surveyed.
Better training for school staff to support children with mental health issues was another priority flagged up in the survey. Just nine per cent of those surveyed felt sufficiently trained to identify the signs of mental health issues. A third said they had not been given any training in spotting mental health problems, while 45 per cent said the training they received was insufficient.
ATL general secretary Mary Bousted said: “It comes as no surprise that so many education professionals are feeling so utterly let down on all sides when it comes to support for children’s and young adults’ mental health.
“The systematic stripping away of social services and CAMHS funding by the current government has left pupils dangerously at risk and, once again, it has been left to school staff to plug the gaps in social care as best they can.”
In his pre-election Budget Chancellor George Osborne pledged £1bn to improve access to mental health treatment for 110,000 extra children and young people this year. A further £118m will also go towards expanding the Children and Young People’s Improving Access to Psychological Therapies programme over the next three years.
But Bousted said this extra investment, “while welcome, smacks of closing the stable door after the horse has bolted”.
Better integration between schools, CAMHS, GPs and youth justice professionals in support for children with mental health problems is among a raft of recommendations unveiled in a joint report by the All-Party Parliamentary Groups (APPG) for children, penal affairs, child protection and looked-after children and care leavers.
The report, published by the National Children's Bureau, also calls for improvements to transition to adult services and more consultation among young people by commissioners in the design of local services.
Baroness Massey of Darwen, chair of the APPG for children, said: “Responding to the mental health needs of children and young people requires a joined-up approach across services, and a commitment to understanding the wider context of a child’s life.”