MERGER plans have been announced that will result in a single health trust running County Durham hospitals.

The radical blueprint drawn up by Prof Ara Darzi is designed to ease pressure on the University Hospital of North Durham by encouraging closer working relationships between hospitals in the North and South of the county, currently run by two separate trusts.

Since it opened last year the privately financed Durham hospital has struggled to cope with demand.

Critics, including North Durham MP Kevan Jones and the public services union Unison, have argued that the Durham hospital was built with too few beds because of the financial deal agreed with private backers.

There have also been allegations that the £67m privately financed Bishop Auckland General Hospital, due to open this spring, is a 'white elephant' and in the wrong place.

After the announcement of the plan, Stephen Mason, chief executive of the 492-bed Durham hospital, said he believed an extension was probably still needed to cope with the demand.

If Prof Darzi's plan is accepted it will mean some patients from North Durham could choose to go to Bishop Auckland to have their operation.

There is also a plan to further expand diagnostic services at Shotley Bridge Hospital, which is currently being redeveloped, so GPs from a wider catchment area could refer patients there for tests rather than to Durham.

As part of the shake-up Bishop Auckland Hospital would become the main centre for routine joint replacement surgery With the bulk of straightforward hip and knee replacement operations done at Bishop Auckland it is expected to free up beds at the Durham hospital.

Prof Darzi, the Department of Health's advisor on surgery and a member of Health Secretary Alan Milburn's modernisation board, spent eight weeks talking to health managers and doctors before drawing up his blueprint.

Ken Jarrold, chief executive of County Durham and Darlington Health Authority, said the public would be fully consulted on any major changes.

"I would hope that we could begin the consultation process by the summer," he said.