Government plans for a radical overhaul of the National Health Service come under a scathing attack today from the former health secretary Frank Dobson.

Writing in The Independent, Mr Dobson says patients will suffer because hospital managers will be distracted by new NHS structures envisaged by his successor, Alan Milburn. The former cabinet minister's criticism follows days of bitter arguments between Labour and the Tories over standards in the health service.

While Mr Milburn predicted yesterday that rows over the state of the NHS would dominate this Parliament, Tony Blair said he was "happy to suffer the consequences" at the next election if the NHS had not been turned round. The Prime Minister pledged in a Sunday newspaper that the system would be "dramatically improved" before the election, expected in 2005. "I am quite willing to be held to account by the voters if we fail."

Mr Milburn, the Secretary of State for Health, proposes turning the best-performing hospitals, to be labelled "foundation" hospitals, into non-profit making trusts with greater freedom over spending. The worst performers, the so-called zero-star hospitals, will be handed to managers from the private sector, neighbouring NHS trusts and charities. A planned statement today by Mr Milburn on the scheme appeared to have been postponed, amid signs of a last-minute rethink.

Mr Dobson casts doubt over his successor's shake-up, saying he is "dubious" about the whole concept. He writes: "Even if they were a good idea, this is simply not the time. Over the next few years the interests of patients, NHS staff and the electoral fortunes of the Government would be best served if everyone in the NHS concentrated on delivering the best care possible in their clinic, on their wards, in their kitchens, in their operating theatres, in A&E units. I fear that the Government's new proposals would mean the reverse.

"Senior hospital managers will be scurrying round, calling meetings about applications for foundation status, spending our money, splashing out fees on the uncaring professions ­ management consultants, lawyers, accountants, valuers. Looking after patients will have to be done in the time left over."

His attack will alarm ministers because it echoes the increasingly vocal complaints by Labour MPs over the latest planned wave of reforms. It also raises the prospect of him spearheading backbench resistance to the changes.

Liam Fox, the shadow Health Secretary, said: "There is very clearly growing internal unrest in the Labour Party between Downing Street and Alan Milburn on one side and Labour backbenchers on the other who are increasingly jettisoning the 'New' out of New Labour."

The problems confronting the Government on health were underlined yesterday when two surgeons from the Kent and Canterbury Hospital denounced the "appalling" state of its accident and emergency unit. Richard Collins and Bob Heddle said conditions were a "catastrophe waiting to happen" and were far worse than those at the A&E department of the Whittington Hospital, north London, which was at the centre of a storm last week over the treatment of Rose Addis, 94.

* Labour Party membership has plummeted by 10 per cent, its general secretary, David Triesman, told BBC Radio 4's Westminster Hour last night. Membership stands at "about 280,000", he said, compared with the 311,000 cited in the party's annual report, published in September. The Conservative Party has 318,000 members.