NHS shake-up 'like gas and water privatisation'
The shake-up of the NHS in England has been likened by doctors' leaders to the privatisation of the gas, electricity and water industries.
Under the changes, regulators will be encouraged to ensure there is fair competition between NHS trusts and private health firms.
But the British Medical Association said the move could lead to some hospitals closing.
The government has always said such a scenario was unlikely.
The intervention by the doctors' union comes as MPs prepare to debate the bill, which will pave the way for GP consortiums and the further opening up of the NHS to the private sector.
The House of Commons' Public Bill Committee is expected to scrutinise the draft legislation this week.
The bill includes provisions to get Monitor, which will become the financial regulator for the health service, to ensure NHS and private hospitals can compete for business.
The BMA said the powers it has are the same as those given to the Office of Fair Trading, which governs the gas, electricity and water industries.
BMA leader Dr Hamish Meldrum said: "Whatever your views of the privatisation of other services, it is certainly not the right model for the NHS. The consequences of failure in healthcare are far more serious than in other industries.
"At best, providers of care will be distracted from their main responsibility of providing excellent services.
"At worst, hospitals will close - not necessarily for appropriate reasons - and large groups of patients will have greater difficulty in accessing the care they need."
Private sector firms already see NHS patients through minor treatment centres that have contracts with the health service, or the patient choice initiative where private hospitals agree to see people with the NHS paying.
But this only accounts for a small fraction of activity. Under the government's plans, the NHS will be opened up to "any willing provider" meaning private firms will be able to get a greater share of the market.
However, unlike most markets, there will be no competition on price. Instead, all hospitals, whether private or NHS, will be forced to treat patients under a strictly regulated range of tariffs for different procedures.
A pool of money has also been set aside to ensure essential services, such as A&E units, are kept running even if the wider hospital is struggling to attract patients.
The future of hospitals under the shake-up, which will see GPs get control of most of the NHS budget, has received a great deal of attention in recent weeks.
The King's Fund has said some hospital units will have to close and even Sir David Nicholson, the NHS chief executive, has accepted they will have to change to survive.
However, in an interview with the BBC last month Sir David said it was unlikely that any would close entirely.
A Department of Health spokesman rejected the comparison with the gas and water industries.
"We agree that the NHS should not be privatised - we are committed to the founding principles of the NHS, free at the point of use, based on need and not on ability to pay."
But she added: "NHS patients should be able to choose a provider that suits them, be it from the voluntary, independent or public sector."