Almost half a million children who are worried about their feelings or behaviour are not asking anyone for help, according to campaigners.
The Children’s Society says its survey of 10-17 year olds in England, Scotland and Wales estimates that up to 464,000 children are not telling anyone about their concerns.
The charity warns that without early support, the mental health of these children could be at risk of deteriorating and reaching crisis point.
More than three quarters of the children in the annual household survey said they had turned to close family members to ask for help with their worries.
Earlier this year society found around 110,000 10-17 year olds were being turned away from mental health services each year because their problems are not deemed serious enough.
Children’s Society chief executive Mark Russell said: 'It’s vital children get help at an early stage to stop issues from spiralling.
'The next Government needs to prioritise access to immediate emotional and mental health support for all children through their school or in their community so they can drop in and chat when they need to.'
