The tall, slim career GP with a clipped grey beard and smoothly parted hair who greets me in his spacious offices scarcely resembles the union baron of popular imagination. He is urbane rather than confrontational, he speaks in measured sentences and seeks to emolliate not agitate. But Dr Hamish Meldrum, who spent much of his career at a medical practice in East Yorkshire and is now resident in Edinburgh, is the head of what has been called the most powerful union in Britain - the British Medical Association (BMA) - and his assessment of the coalition government's reform programme is devastating, all the more effective for being delivered with the calm of a doctor seeking to reassure a particularly anxious patient.

Meldrum knows that - unlike politicians and indeed journalists - doctors, his members, largely retain the respect and admiration of the public. He would agree with Nigel Lawson that "the NHS is the closest thing we have to a national religion in this country". And he knows that BMA members, denounced by many ideologues on the right as reactionary and unwilling to embrace necessary market reforms, are more powerful than any other interest group when they choose to mobilise against what they consider to be unnecessary and dogmatic interference by politicians.

Mission impossible

He is anxious that the principles of "universality" and "comprehensives", on which the NHS was founded, are imperilled by the fantasy of the Health and Social Care Bill and the creation of a utopian marketplace in which private providers compete with state care. "We are facing a perfect storm, or should that be an imperfect storm," Meldrum says as he sits perfectly still in a stiff-backed chair in his dimly lit office at the BMA's headquarters in Tavistock Square, central London. The "perfect storm", as he outlines it, is this - "impossible efficiency savings being forced on the service", the biggest reorganisation in the NHS's history, "rising medical unemployment", "pay cuts for doctors", "increased waiting lists" and the fear that the strain on the service will lead to more disasters such as the one at Mid Staffordshire NHS Trust.

“The health-care system is being asked to make £20bn of efficiency savings," he says gravely. "In real terms that's savings of 4 per cent year on year, which has never been done in one year before, far less four years in a row. And you've now added into the mix a major structural reorganisation, with lots of people either losing or changing their jobs; or their minds being focused on the reorganisation rather than on making the savings. We are facing various levels of impossibility."

He says even Andrew Lansley has conceded that "the substance of what he wanted to do could have been done without legislation. But in choosing to have legislation, and such permissive legislation - this was to be the legislation to end all legislation - he set a huge number of hares running, some intentionally, some unintentionally, and those who were most against his reforms were given a field day . . . They were able to say that he wanted a market red in tooth and claw, to let competition run rife, to bring private providers in from all over the place . . . ."

Should the Health Secretary resign or be reshuffled out of the cabinet? Even Lansley's supporters believe that he could have been smarter, more pragmatic. His "big bang" reorganisation need not have been so permissive; he could have acted as Michael Gove has done with education. After all, the free schools and academies reform programme is merely a continuation of what was started under New Labour: evolution rather than revolution, with Gove recast as a more zealous (and Scottish) version of Andrew Adonis.

“The policies have to change," says Meldrum of the hapless Lansley, self-styled all-knowing impresario of NHS politics. "Even if the only way the policies change means the current incumbent goes - they have to change."

The good doctor continues: "The Lansley reforms are a folly in terms of health-care issues but politically they are a huge folly as well . . . Leaving aside the reforms, because of the present economic and budgetary pressures, there's no doubt by the time of the next election, if not before, there will be increased waiting lists, [for which] everybody will blame the reforms."

Fewer young people are applying to study medicine at university, perhaps because of the introduction of higher tuition fees. "Will it lead to a shortage?" Meldrum asks. "We are educating and training more doctors than we used to, but can we afford to employ them? In the UK we have below-average numbers of doctors per head of population compared to Germany, France and others. On average every GP looks after about 2,000 patients. As people live longer, have more complex and long-term conditions . . . I think that ratio is wrong. Do we need more doctors? Yes. Can we afford more? Much more difficult."

Overworked, understaffed

Meldrum worries about the "potential for medical unemployment. In the past, we have scandalously relied on doctors from overseas, often from countries that can least afford to give them to us, to back up the gaps . . . We are already seeing [the impact of not having enough doctors] - consultants taking on more of the work that junior doctors used to do; that in some places the time available for continuing education and continued training is being limited and that can only be bad, not only for doctors but for patients.

“Also you get trusts that try to stretch rotas or stretch the staffing of wards too thinly - well, then accidents will happen and people will fall through the gaps and you may see the sort of things that happened in Mid Staffs, where part of the problem was the failure to attract enough doctors and nurses to cope with the work that was being asked of them."

What is most worrying for Meldrum and the medical profession he represents is that the Lansley reforms have made it much easier for opponents of the NHS to say that "it's the system that's bust rather than the funding of it, [and we will] see increasing pressure for co-payment or top-up payments, for limiting the scope and comprehensiveness of the health care provided by the NHS, and . . . it will be done on the wrong premise".