GPs are fighting a PCT's decision not to hold a public consultation before putting a practice out to tender.
GPs in South Woodham Ferrers are awaiting the result of an appeal against NHS Mid Essex over the process.
The surgery was taken over in December by private company The Practice, which successfully bid to run it. The practice in question was previously called New Surgery, but along with all surgeries the firm runs, now operates as The Practice.
Local GPs and residents opposed the PCT's decision not to hold a consultation. South Woodham Ferrers Town Council held a meeting with NHS Mid Essex chief executive Sheila Bremner in November 2010 to express their concerns.
Town councillor Jackie Birch said changing the provider 'would inevitably lead to a change in services' and patients should have been involved.
But the PCT, which is considering the appeal, said no change to services was planned. Dr Andrew Hildrey, clinical chairman of primary care at NHS Mid Essex, said: 'The PCT is fully aware of and complies with its duty to involve patients in the planning of any new or significantly changed services.
'In this case no changes were planned to the provision of services or the way in which they were provided.'
The PCT says a patient representative from New Surgery took part in discussions and their views were highly valued.
However, GPs and councillors have voiced concern that the PCT has not made the identity of the patient representative public.
Local GP Dr John Cormack said the PCT should have held a public consultation, because a change of provider meant a change to services. 'Changing from a standard set-up to a private company is the most significant change a GP practice can undergo,' he said.
Dr Cormack warned that the appeal against the PCT's decision not to hold a consultation could lead to other PCTs acting in a similar way.
'I think that if Mid Essex PCT gets away with it, other PCTs will use it as an excuse to do likewise,' he said.
He said GPs should 'do their best to ensure clinicians and patients get a say in all important decisions'. If the appeal fails, the next step could be to seek a judicial review, he said.
The Practice, which has run the surgery since December, said that it was aware of the appeal but was not involved by the PCT in the detail.
A spokeswoman for The Practice said: 'As far as we are concerned we followed the tendering process as set out by the PCT and had no reason to believe it was anything but fair and transparent.'