A South African private healthcare firm will next month take over the running of two 43-ton vehicles carrying £1m mobile operating theatres in the latest attempt to cut long NHS waiting lists.

The mobile theatres are due to provide cataract operations to more than 41,000 NHS patients in the next five years. One will tour the north of the country and the other the south, stopping in towns where a demand for their services has been identified.

GPs will be able to refer patients for operations using an airline-style booking system over the internet.

John Reid, the Secretary of State for Health, announced yesterday that the contract to run the mobile theatres had been awarded to Netcare, at a price said to be almost 10 per cent less than the comparable NHS cost. Netcare is South Africa's largest private healthcare organisation and runs 44 hospitals with 7,000 beds and 53 primary care centres.

It is already involved in four areas of the UK, and has undertaken 300 hip and knee operations in Southport, Merseyside, and almost 1,000 cataract operations in Morecambe Bay, Lancashire. All procedures are paid for by the NHS. Mr Reid said: "Targeting cataract removal means we are addressing a relatively simple procedure but one of the most common and widespread conditions.

"By touring the country the treatment centre provides NHS services where they are needed most and leaves the existing NHS facilities to concentrate on more complex activity."

That remark drew charges from the Liberal Democrats that the treatment centres - of which 80 are due to be up and running by 2005 - would cream off the easy and profitable operations, leaving the NHS to cope with the difficult, high- cost ones. Paul Burstow, Liberal Democrat health spokesman, said: "The test for diagnostic and treatment centres is whether they increase the health service's ability to treat more people. If the centres simply divert operations from existing NHS facilities and increase costs for the NHS then they will have failed."

Richard Friedland of Netcare said the two mobile theatres, accompanied by mobile ward units and out-patient facilities, would each treat 20 patients a day and be run by 36 doctors, nurses and anaesthetists brought to Britain from South Africa. They would operate six days a week throughout the year, except bank holidays.

"We will be operating to maximum efficiency on the road six days a week to keep costs down," he said. All medical staff would be fully qualified and selected in accordance with NHS regulations. Receptionists, call centre staff and computer operators would be recruited in the UK.

"We are very strictly bound by the contract not to employ anyone from the NHS or who has worked for the NHS in the previous six months. All our staff go through a very strict selection procedure and they are experienced ophthalmologists and anaesthetists." To prevent poaching of medical staff from South Africa, they would be employed on rotation, with contracts from a few weeks to six months - though in some cases that might be longer, he said.

Britain has an agreement with South Africa not to poach its medical staff after an appeal from Nelson Mandela five years ago. Under plans announced last year, seven private companies including Netcare, are due to set up and run 34 of the new treatment centres, on behalf of the health service. The first one opened in Daventry, Northamptonshire, last October and has carried out 850 cataract operations. A further 46 centres will be run by the NHS, of which half are open and the remainder are in development. The 80 treatment centres run by private agencies and the NHS plan to provide 250,000 treatments a year from 2005.

Of these, 135,000 will be additional and 115,000 will be transferred from local hospitals to the privately-run centres to free up capacity within the health service.

The British Medical Association (BMA) said the treatment centres were a short- term solution to long waiting lists and did not address the NHS's fundamental problems. It said the health service was moving from a provider of services to a funder of private agencies. Paul Miller, the chairman of the BMA consultants' committee, said: "We are worried that the mobile treatment centres could destabilise NHS services if they perform the most straight-forward operations while the NHS is left looking after the more ill and complicated patients and left to handle services at nights and at weekends."