The NHS is too vast for politicians to hand over to an independent board to run, the health secretary has said.
Mrs Hewitt said more powers should be devolved to patients and GPs
Patricia Hewitt said the proposal, favoured by the British Medical Association, would turn the NHS into a "1960s nationalised industry".
But she said more power should be given to patients, GPs and health staff.
Mrs Hewitt was heckled by a handful of "Keep our NHS public" campaigners who say the NHS is being privatised, as she gave her speech.
Last year Gordon Brown was reported to favour handing over day-to-day control of the NHS to an independent board - in the same way he gave up control of interest rates to the Bank of England in 1997.
And in May the British Medical Association called for an end to "constant political dabbling" in the NHS, and the establishment of a board of governors and executive management board to run the NHS.
But in a speech about the future of the health service, Mrs Hewitt told the London School of Economics: "The NHS is four times the size of the Cuban economy and more centralised.
"That is part of its problem, and the problem can't be solved by proposing that a modern health service be run like a 1960s nationalised industry."
She said a free, comprehensive NHS was "under attack" - pointing to recent comments from Doctors for Reform and the BMA.
But she added that NHS structures of the 1940s and 1960s were not right for the NHS now, and needed to be more "patient led", financially disciplined, well regulated with a "plurality of providers".
She denied creating a "free market" within the NHS, but said that competitive pressure could create "startling results for patients".
"I can think of no greater sanction against poor services than allowing patients to vote with their feet," she added.
She also said that she backed an NHS constitution, which could cover behaviour expected of NHS patients and people's personal responsibility for their own health.
Mrs Hewitt was repeatedly interrupted as she answered her speech by protester Shirley Murgraft, 76, and Lois Austin.
They said that increased pressure on beds and waiting times meant more patients were being forced home early, when they had not properly recovered.
Protesters also stood outside with banners reading "SOS NHS" and "NHS not for sale".
Among them was Eileen Smith, 75, a former NHS clinical nurse manager, who was concerned about the scrapping of patients' watchdog the Community Health Councils and the lack of inspection rights in private hospitals.
"I believe healthcare should depend on need and not put profits into people's pockets," she said.