Controversial plans to overhaul the NHS in England have passed their first Commons hurdle after a six-hour debate.

Health Secretary Andrew Lansley said they would make the NHS "fit for the demands of the 21st Century".

But Labour said "free market political ideology" was driving a plan that would break up the NHS.

The bill was backed by 321 to 235 at second reading. No coalition MPs voted against the government although Lib Dem Andrew George deliberately abstained.

Mr George had indicated during the debate that he would not vote for the plans, which he said were "well intentioned" but needed "major surgery".

Earlier David Cameron admitted his brother-in-law, a hospital doctor, had told him of doubts among colleagues about the plans.

MPs have been debating the Health and Social Care Bill, which includes plans for all 151 primary care trusts and strategic health authorities to be disbanded.

The bill still has further Parliamentary stages to go.

So far, 141 GP consortiums, serving more than half of the population of England, have signed up as "pathfinders" to pilot the new arrangements.

'Unaffordable'

Mr Cameron told BBC One's Breakfast that with a growing elderly population and the cost of new drugs and treatments, without cutting "bureaucracy and waste, I think it will become increasingly unaffordable. The risk is doing nothing."

The PM says that without modernisation the NHS will be unaffordable. What he did not spell out is why Nick Robinson, BBC political editor In quotes: Debate on future of NHS Read Nick's thoughts in full

He added: "There is no privatisation taking place. The NHS will be just like you experience it now - it is free at the point of use, you don't pay anything, and it is according to your need.

"But I think it is a good thing if patients and their GPs are able to choose between different providers."

Opening the debate in the Commons, Health Secretary Andrew Lansley said the previous Labour government had increased resources to the NHS without achieving "European-level results".

"We spent more, others spent better," he said.

"The purpose of this bill can be expressed in one sentence, to improve the health of the people of this country and the health of the poorest fastest."

Mr Lansley said the government would "stop the top-down, politically-motivated targets" and would "focus on the outcomes that really matter".

'Not a revolution'

But he said the bill was "not a revolution" and followed Labour policies developed under Tony Blair which had been implemented "incoherently".

"Previous changes have tinkered with one piece of the NHS or another when what was needed was comprehensive modernisation - an NHS fit for the demands of the 21st Century and that is precisely what this Health and Social Care Bill will deliver.

"What we see from the party opposite is nothing but opposition for its own sake... opposition which in most cases is inconsistent with their own manifesto."

Labour MPs lined up to criticise the plans. In his first Commons speech since losing the Labour leadership to his brother, David Miliband said the proposals represented a "set of poison pills" for the NHS.

These changes will break up the NHS John Healey, Shadow health secretary

Margaret Hodge said it was "unnecessary institutional reform", while Jim Cunningham demanded to know how many jobs would go and how many hospitals would close as a result of the plans.

Shadow health secretary John Healey told MPs: "The health secretary is a man struggling to sell his plans. The more people learn the less they like them."

He said most GPs did not want the changes and compared Mr Cameron's TV interview with "a football club chairman stepping in to back a beleaguered manager because everyone else is losing faith in his judgement".

Mr Healey aimed his arguments at Lib Dem MPs, saying: "This is not Liberal Democrat policy but it's being done in their name and the public will hold the Liberal Democrats responsible if they allow the Tories to do this to our NHS."

He said the bill "puts competition first and patients second", adding: "These changes will break up the NHS."

Media playback is unsupported on your device Media caption Mr Cameron said he wants to cut the "level of bureaucracy and waste" at the NHS

But the chairman of the health select committee, Conservative MP Stephen Dorrell, said: "This bill actually represents an evolution of policy which has been consistently developed by every secretary of state with a single exception since 1990."

The NHS Confederation has warned that hospitals could go bust by opening up the NHS to "any willing provider".

Dave Prentis, the general secretary of Unison, the public sector union, said the "titanic reorganisation" threatened to sink the NHS. The Unite union warned it would "allow NHS staff, skills, buildings and resources to be snatched by profit-hungry companies".

The changes were first set out in a white paper published last summer.

They apply solely to England - Scotland, Wales and Northern Ireland have different systems.