A British soldier from B Company, 2 Mercian keeps watch at the Malgaeer village in Helmand province July 26, 2009 file photo. REUTERS/Omar Sobhani

LONDON (Reuters) - More than twice as many former British servicemen are in prison, on probation or on parole than are serving in Afghanistan, the Guardian reported on Friday.

According to probation officers’ union Napo, some 20,000 veterans are in the criminal justice system, with 8,500 of them in jail, making up almost 10 percent of the prison population, the Guardian said.

“There is overwhelming evidence that support is not available of sufficient calibre when soldiers leave the service,” Harry Fletcher, Napo’s assistant general secretary, told the newspaper.

“The preponderance of post-traumatic stress disorder and depression is also alarming.”

The Napo survey of 90 cases of convicted veterans found nearly half suffering from post-traumatic stress disorder or depression as a result of their experiences in Northern Ireland, Bosnia, Iraq and Afghanistan.

The proportion of Britain’s prison population who are veterans has risen by more than 30 percent in the last five years, according to the report.