Calls for the NHS to be taken out of Government control and run by an independent body have been rejected by Health Secretary Patricia Hewitt.
In a speech to the London School of Economics, Ms Hewitt said such a scheme would not work because of the size of the NHS.
The British Medical Association (BMA) has called for an end to "political dabbling", while Gordon Brown has reportedly been in favour of handing over day-to-day control of the NHS to an independent board.
But Ms Hewitt rejected the idea. She said: "For a growing chorus the answer is 'independence'.
"Let's just think about this. Start with size and scale. The NHS in England will spend over £90bn this year.
"If the NHS was a country, it would be the 33rd biggest economy in the world, larger than new European Union transition economies like Romania and Bulgaria.
"Would the Prime Minister of such a nation seriously propose to take the entire economy and put it under a single independent board, every organisation in the hands of one owner, run as one entity? Of course not."
Ms Hewitt said that, despite the myth of ministers controlling every local decision, "we have already taken significant steps towards creating an independent, self-improving NHS".
She pointed to the work of local managers and the creation of the much-criticised National Institute for Health and Clinical Excellence (NICE).
"It took the power to determine what drugs and technologies the NHS should use away from politicians and placed it in the hands of clinicians - and is now the envy of the world," she said.