Not-for-profit group Nuffield has acted to stop consultants, who do private work at its hospital in Old Milverton, from poaching patients and staff for potential rival Circle's proposed hospital near Warwick.

Nuffield believes 41 doctors have placed themselves in conflict after signing an agreement with the new firm, which it claims commits them to transferring patients away.

Some are said to have encouraged their colleagues to sign up - and Nuffield has withdrawn one consultant's right to practise because of this. He is appealing.

A Nuffield spokesman said: "It has become clear that a small group of consultants who hold practice privileges at the Nuffield Hospital Warwickshire have placed themselves in a direct commercial conflict with the hospital by signing agreements with a potential competitor.

"These are contractual commitments guaranteeing that they will transfer a significant proportion of their private practice to a proposed new hospital.

"A few have gone further and have actively promoted the interests of a competitor, for example by recruiting other doctors to sign up to the competitor, which will result in patients being taken away from us, or by soliciting staff."

Nuffield stressed it did not believe the 41 consultants linked with Circle had acted in bad faith but had not understood the implications of signing agreements with Circle.

It also defended its right to withdraw support for those acting against its interest.

The Old Milverton hospital, which was built in 1981, does not currently carry out any NHS work, although

Circle has announced its intention to bid for this under the government's 'patient choice' policy.

Nuffield managers predict this choice, which Circle says will benefit from a new hospital, may be an illusion if doctors who have signed the agreement are obliged to refer patients to the new private company as a result.

The spokesman added: "We believe that the contracts that the doctors have been asked to sign - and which they may be bound into for several years - oblige them to direct a proportion of their patients to the proposed hospital, should it ever be built.

This obviously raises questions about patient choice."

Circle's managing partner, Dr Ali Parsa, described the rival firm's allegations about the written agreement as "unfounded" and said Circle was only asking its consultants to bring 40 to 50 per cent of those patients where the doctors are able to decide where to send them for treatment.

He compared Nuffield's "monopoly" in south Warwickshire to that of British Leyland or British Telecom before privatisation and stressed the final choice remained entirely with patients.

Dr Parsa added: "Patients will always have a choice of where they want to go and if 100 per cent of them want to go to Nuffield, rather than a brand new hospital, that is fine.

"But right now, 100 per cent of patients have no choice but to go to the Nuffield Hospital."