Prisoners in need of treatment at secure mental health hospitals often have to wait months for a bed, the director of an NHS trust has said.

Dr Nick Broughton, medical director of West London Mental Health Trust, said: “Medium-secure services are funded to be full at all times - there is 100% occupancy. We don’t always have spare capacity for people who need to come to us.”

The speed at which patients are housed in the community after being deemed fit to be discharged is a “major problem”, he said during a central London briefing by specialists from secure mental health facilities.

“There are limited places available,” said Dr Broughton. “Funding for hospital accommodation isn’t funded by the health budget, but by social care budgets, and they are under a huge amount of pressure.

“This is a major concern for us. Getting enough placements in the community is the issue.

“We’re worried about what the economic crisis may mean in terms of community placements - and it’s something we have no control over.”

He said the trust was also dependent on charitable organisations to help with the shortfall in funding, but estimated that a further 10% to 20% more beds were needed in medium-secure units than are currently available.

“It’s difficult to ensure patients are discharged when they need to be discharged,” Dr Broughton added. “That, in turn means it’s difficult to make sure there are beds available.

“It can mean they languish in prison longer than we would like.”

He said patients spend “weeks, if not months” waiting to be transferred to hospital, adding that this needs to be reduced to a maximum of one to two weeks.

In some cases, the trust has to pay for patients to be transferred to private secure hospitals, if NHS units are full.

Dr Broughton, speaking at the Science Media Centre, added: “They accommodate the NHS overspill when NHS units are full, and the patient needs to be in hospital rather than in prison.”

A Ministry of Justice spokesman added: “Working with the Department of Health and the National Treatment Agency, we are considering how the provision of residential and other intensive treatment in the community can help those offenders who want to beat their addiction.”