Doctors' leaders have rejected the government's revised proposals for the NHS in England, saying they are "one of the biggest social injustices".
Members of the British Medical Association (BMA) refused to back the Health and Social Care Bill as it currently stands, not demanding that it be scrapped completely, but saying it needs to be tougher.
Under the reforms, GPs would receive financial rewards in appreciation of how well NHS budgets are run.
BMA member Dr Jacqueline Applebee, one of 20 doctors listed to speak against the proposed bill, said: "Privatisation has been covertly going on under the radar for more than 10 years in the health service. We must never forget that private companies work on profit, not need.
"The introduction of personal health budgets will provide easy pickings for health insurers.
"Commissioning boards will be able to charge for services they deem not appropriate on the NHS.
"If this bill is passed, the government will be administering one of the biggest social injustices placed on the British people."