Plans for major reform of the NHS set out by Health Secretary Andrew Lansley have come under fire.
According to the Royal College of GPs (RCGP), the relationship between doctors and their patients could be at risk as a result of the reforms.
The group also warned of the cost and speed in which Mr Lansley wants to bring about change in the health service.
The RCGP said it had grave concerns about the use of private companies to run NHS services, adding that the "loss" of the expertise offered by NHS trusts would be sorely felt.
The issues raised by the RCGP are similar to those raised by the Royal College of Nursing (RCN) and the British Medical Association (BMA).
While the RCN supports the underlying principles of giving health workers greater freedoms, it has said the proposals are "untested".
The BMA said it was not against the whole vision, but had concerns that the changes could affect the service's "stability and future".
And Unison has warned of possible instability, saying this could have an impact on patients.
The RCGP response said members were receptive to the principles of greater GP leadership and influence.
But it added: "Many GPs are concerned that a system of GP commissioning will lead to the erosion of the crucial relationship between GPs and their patients.
"Heretofore GPs have seen their role as being an advocate for their patients, prescribing the best course of treatment for the individual's healthcare needs.
"We are sure that GPs will continue to be so, but worry that this may be open to public doubt when GPs, in their role as commissioners, are also responsible for the allocation of resources."
While members of the College accept the need for a debate on the rationing of limited resources, they would "find it unacceptable if this were to take place at the level of the individual GP and their patient."
Professor Steve Field, RCGP chairman, said: "Our members - 'jobbing' GPs throughout the UK - can always be relied upon to act professionally and constructively, with the best interests of our patients at heart.
"We feel that this response is as comprehensive as possible and that it appropriately reflects and represents the views of RCGP members."
A Department of Health spokesman said: "We welcome the constructive comments from the RCGP and will take these and all the comments into consideration as part of the consultation."
Copyright © Press Association 2010