The number of under-16s admitted to inpatient care outside of their area on mental health grounds has increased by 28.5 per cent, from 294 in 2010/11 to 378 in 2014/15.
The figures, released in response to a parliamentary question by Labour MP Sadiq Khan, reveal that since 2010 a total of 1,821 under-16s have been treated out of area, as well as 3,020 16- to 18-year-olds.
The number of 16- to 18-year-olds treated out of area has risen by two per cent in the last five years, from 589 in 2010/11 to 601 in 2014/15.
A report published last month by the Mental Health Taskforce states that out-of-area placements for acute care still need to be “reduced and eliminated” as quickly as possible.
Experts in the field have called for action to address the issue of out-of-area treatment.
Paul Burstow, chair of the Tavistock and Portman NHS Trust, said the rising numbers of children being treated away from home is a sign of “pressure in the system”.
“There is a need for investment in new models of children and young people's mental health to deliver home treatment and crisis resolution,” he said.
"NHS England needs to spell out soon how they will deliver the Mental Health Task Force recommendations for age-appropriate crisis resolution and home treatment,” he said.
Max Davie, children’s lead at the Royal College of Paediatrics and Child Health said that “in a system that works” virtually no children should require out-of-area treatment.
“There is a lot of talking but little action on the ground," he said.
"If we had developed systems around children and young people’s mental health, we would have lower numbers.”
He said that child and adolescent mental health services (CAMHS) need to change from a system where early intervention services sit separately from other services.
“Experts should come down from their escalated position to work with people on the ground to get early intervention earlier on,” he said.
“Being treated away from home makes you feel like there’s more wrong with you than there really is. It can be alienating; you feel alienated from your community and family,” Davie said.
Paul Farmer, chief executive of mental health charity Mind and chair of the Mental Health Taskforce, said the figures highlight the scale of the task ahead for the government.
“The year ahead will be critical for implementing better support for children and young people. We know the money is there but we really need to see changes happen,” he said.