Inequalities in the provision of specialist child mental health services have worsened in the last seven years, a survey shows.
Inequalities in child mental health services have widened
The Royal College of Psychiatrists found the number of in-patient beds in England had risen from 844 to 1,128.
But they said the biggest increases had been seen in the south east and London which already had the highest concentration of services.
Campaigners said improvements in services were urgently needed.
Beds for NHS mental health patients are provided by both the private sector and the NHS.
The college's survey in 1999 found that in-patient provision of child and adolescent mental health services (Camhs) were unevenly distributed, largely due to a concentration of units managed by the private sector in the south east.
A repeat of the bed count survey was conducted in 2006 to see whether change had occurred in response to government policy, which has called for equitable access to good quality services.
As well as the increase in beds, the poll found the total number of units had risen from 72 to 91.
Two thirds of the increase in beds was a result of greater private sector provision, leaving the NHS responsible for less than two thirds of beds.
The report found that regions with the highest number of beds in 1999 had increased bed numbers by 8.3 beds per million people, compared to 3.6 beds per million in the areas with the lowest provision.
It means 75 of the 113 beds set aside for eating disorders now are confined to four units in London.
And the 183 secure and forensic beds provided by 12 units are located in six of the 10 health regions.
The college also said that despite an overall increase in bed numbers, four regions were still well below the recommended minimum of 20 beds per million people.
Researchers blamed fragmented local commissioning and the effects of market forces due to increasing privatisation.
They added: "In-patient services for children face an uncertain future."
Andy Bell, of the Mental Health Alliance, an umbrella group of charities and professionals, said: "There is a recognition that child mental health services need to improve.
"But they are starting from a very low base and we need to see change quickly.
"The problem is that where there are not specialist services, children are forced into adult units or go without."
A Department of Health spokesman said £31m had recently been made available to improve the provision of child mental heath beds.
He added: "We have taken decisive action on children who are placed in adult psychiatric wards.
"We are on track on our commitment to ensure that no child under 16 will be treated on an adult psychiatric ward by November 2008."