The number of patients treated at Redwood Hospital in Surrey will more than double next year when it becomes an "express surgery centre" for routine operations on the NHS.

The small private hospital will stop treating Bupa patients and, by the end of 2002, will have become a fast-track centre exclusively dedicated to cutting NHS waiting lists.

The hospital will provide hip and knee replacements and cataract operations for up to 12,000 NHS patients a year, doubling the amount of NHS work done by Bupa.

It is the first of 20 "diagnostic and treatment centres" the Government promised to provide by 2004, which are to be run either by the public or private sector. It still be owned and managed by Bupa but, in a partnership with the Surrey and Sussex Healthcare Trust, the operator will bill the NHS for the work carried out.

Clinical services will be provided by a combination of Bupa staff and NHS employees, including a team of 20 nursing staff from the surgical unit at the Surrey and Sussex trust.

Richard Jones, operations director for Bupa hospitals, said: "Under this venture, we are proposing to treat 12,000 patients a year, a dramatic increase on now."

Bupa said it would pay for the "reconfiguration" of the centre and for major investment in its nearby Gatwick Park Hospital, which will then take all its local private patients.

Redwood has the advantage of being on the same site as East Surrey Hospital in Redhill, one of two NHS hospitals serving the area. It will concentrate on reducing the longest waiting lists in orthopaedics and opthalmics, which currently mean that a patient could wait up to 17 months for a hip replacement or more than a year for the removal of cataracts.

If patients "bought" the operations privately through Bupa, they would have paid £6,000 to £9,000 for a hip replacement, £6,800 to £9,600 for a knee joint and between £2,000 and £3,000 for cataract surgery.

Those prices would not apply under the new partnership because Bupa will provide operations at "contract" prices, details of which have not been released.

Ken Cunningham, chief executive of the Surrey and Sussex trust, welcomed the scheme yesterday as the "quickest way" for him to reduce patient queues. He said "It is a good deal. It gives me more capacity, so patients will have shorter waits."