As trade unionists, anti-cuts campaigners and health workers demonstrate in protest at planned health reforms, Lord Owen warns that the NHS could be unrecognisable in 10 years' time.

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The "block the bridge" protest was described ahead of the event as a "spectacular act of mass civil disobedience".

The location of the protest was symbolic: Westminster Bridge links one of London's biggest hospitals, St Thomas's, and the Houses of Parliament where peers will debate the NHS reforms.

The controversial health and social care bill is due to go before the House of Lords on Tuesday and Wednesday of this week, ahving made it through the Commons after some redrafting.

The government says the bill would open up the NHS to "healthy competition", equalling more power to the patient and better care.

Shadow Health Secretary Andy Burnham said the bill "unpicks the fabric of the NHS, takes the 'N' out of the NHS and turns it into a free-for-all, a huge postcode lottery".

Mark Serwotka, general secretary of the Public and Commercial Services union, said: "The government's health and social care bill represents the gravest threat to the NHS, one of our nation"s finest achievements, since its foundation."

Last week more than 400 experts sent an open letter to the House of Lords urging peers to vote against the bill. Dr David McCoy, associate director of public health for inner north west London, told Channel 4 News their concerns were prompted by fears about the commercialisation of the NHS in England.

"It means opening up the private sector to the market by making everything provided to the NHS subject to competition," he said.

But Health Secretary Andrew Lansley, addressing the Conservative Party conference in Manchester last Tuesday, said he would never preside over a health service that was "fragmented, privatised or undermined".

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'Unrecognisable' in 10 years' time

Crossbench peer Lord Owen, who is a doctor, told Channel 4 News that if the health and social care bill was passed, the NHS would be "unrecognisable" in 10 years' time. He said the bill was far more far-reaching than people understand.

"The NHS stands for some ethical and altruistic elements in society," he said.

(The bill) effectively will mean that there will be a commercialisation of the health service. Lord Owen

Lord Owen conceded that the Lords could not wreck the bill and could only aspire to improve it. But he warned that as the bill stood, the health secretary was "abdicating from practically every power".

He said the NHS was "overall understood to be under democratic control - there is answerability, and people have to look to parliament. And by and large, parliament has protected the national health service."

He continued: "It is privatisation... It effectively will mean that there will be a commercialisation of the health service, and the values will be that of the market."