On a cluttered desk in a modest third-floor office in St Vincent's Public Hospital, there's a photo of Professor John Crown, consultant medical oncologist, with health minister Mary Harney. Taken at some long-forgotten function, back in the day, the pair clasp hands and smile for the camera. The moment is unlikely ever to be reprised.

"She has been a huge personal disappointment to me," says Crown, one of the most vociferous advocates for health-service reform in Ireland. "I was one of her absolute fans, and believed her to be a good and principled politician. But she came into the job with simplistic notions, founded on the beauty of free enterprise.

"Her adviser was someone whose expertise lay not in healthcare but in implementing administrative fiats. She thought that all she had to do was crush a couple of big vested groups, implement the wish list of the civil servants and incentivise as many people as possible to get out of public and into private healthcare so that they would be less of a drain on her low-tax fanbase. A rump public service would exist only for the indigent and the poor.

"There are huge subtleties in the health service which she has failed to appreciate, and now there is too much face to be lost from a change in direction. I believe there will be no meaningful change in the health service under the current minister."

Born in Brooklyn, the only child of first-generation Irish emigrant parents – his father had the candy store on the corner and his mother worked as a nurse – Crown arrived in Ireland in 1967 at the age of 10 and was schooled at Synge Street and Terenure College before going on to study medicine at UCD. He was, he says, drawn to specialise in cancer from an early age and, after UCD medical school, trained in New York at the prestigious Mount Sinai and Memorial Sloane Kettering hospitals (the latter, by reputation, the best cancer hospital in the world) where he became a consultant oncologist. He returned again to Ireland in 1993 so that his three children, now in their late teens and early 20s, could grow up here.

He was only the fourth consultant oncologist to be appointed in the country (There are still only 20). There had not been a job opening in 10 years.

"The cancer treatment system that I came back to was, with the benefit of 16 years hindsight, primitive. Men – politicians and doctors – had let it be primitive. There was a huge amount of complacency. Even then, other countries that were less well off had far better systems than we did. Radiotherapy was available only in Dublin and Cork, oncology only in Dublin. Many doctors were unduly traditional in their approach to cancer management.

"Naively I saw myself leading a rabble of scythe-wielding consultants to the barricades, 1848-style, to demand a revolution in cancer care. But when I looked behind me there were rather fewer of them than I had thought there would be."

Crown has been causing trouble ever since. He had his knuckles rapped by the hospital authorities for a 1995 interview with this newspaper in which he criticised inefficiencies within the hospital. Funding for new buildings had been put in jeopardy, he was told. He should shut up.

"I don't mind the grief that comes with sticking my head above the parapet as much as I used to. There was a real chance that I would get fired back in the first few years I was here. I'm still conscious of political and administrative vulnerabilities on a daily basis, but will not be silenced if something needs to be said."

Away from the politics, the substance of Crown's practice continues to excite him.

"The war on cancer has made extraordinary strides in the last 10 years. For a while there was a schism between what was happening in the labs and what doctors in hospitals were doing. For a long time, chemotherapy was a blunt instrument, but there is a new generation of magic bullets that are specific in terms of treatment and less injurious in terms of side effects. Outcomes for bowel cancer and for one type of leukaemia and another of breast cancer in particular have been revolutionised. The kind of stuff I did in medical school has been confined to obsolescence.'

While substantial scientific challenges remain, Crown sees the cost of treatment as the biggest challenge facing the health service today. "There is the potential for a perfect storm in terms of health economics. The cost of cancer care has to be addressed.

"Healthcare is becoming more expensive – it's not infinite but it is large. There is a requirement for more spending on cancer patients, both in terms of the drugs they need and the other costs they incur if they stay alive. No one questions that hard decisions will have to be made, but they need to be made in a very sophisticated fashion."

Which brings us to the rub. Who is capable of making those decisions? Not, in Crown's view, the Department of Health mandarins, whom he believes to be divorced from reality, unfit for purpose and having the most vested interests in maintaining the status quo.

Crown's trenchant opinion is that current structures within the Irish health services incentivise neither quality nor efficiency. He is an advocate of the Bismarckian system, which remains largely intact in Germany and has been copied successfully in many other countries, over the Beveridge model which currently applies in our public hospitals. He explains the difference thus:

"Under Bismarck, which is a system of social insurance, we all admit that we are in this together. Everybody pays a mandatory fixed contribution, a percentage of their income, into sickness fund – a not-for-profit fund which pays doctors and hospitals according to the activities they perform while policing that there is no over-prescribing or over-utilisation of tests for the enrichment of doctors and hospitals.

"Under Beveridge, general tax revenue is applied by central government to the healthcare system owned by it. The hospital gets a fixed amount of money and is told to make it last for the year. The inevitable reaction to an increase in demand is that when the hospital runs out of money at the end of the year it starts closing wards and cancelling operations, thereby lengthening waiting lists. The best example of this is Susie Long. Poor Susie died because her hospital did not incur any costs until she crossed the threshold – as long as she was on a waiting list she was free.

"Under the Bismarckian system her hospital would have made money when she came in, and so it would have been heavily incentivised to take her and treat her. As a system, Bismarck tends to be more expensive but effectively there are no waiting lists – they are a consequence of the system we use."

Crown blames the 'command-and-control' model under which the leadership in our hospitals comes from bureaucrats rather than doctors for the current situation. So long as the administrators avoid major scandal and stick to budget they are perceived by the department to be doing a fine job.

"In the great US medical centres, the doctors provide the vision and the managers the niche and technical skills. Here, the bureaucrats are the leaders and they regard the doctors' ability to look after patients as a niche service."

Another timely issue, about which Crown feels strongly, is the whole question of ownership of hospitals. He is, he says, "very troubled that St Vincent's and the Mater have boards appointed virtually entirely by religious orders and, in the case of the Mater, by religious orders and by the archdiocese of Dublin. The Catholic lay organisations are strongly represented on those boards."

The hospitals are 100% state funded, but there is no democratic accountability at board level in terms of who makes the decisions. It is not, he says "just ornery-ness or pernickety-ness" on his part that objects. There are real practical implications for patients.

"Some years ago," he says, "there was a dreadful episode where cancer treatment protocols were being delayed and in some cases denied to patients because they stipulated that patients participating in a drug trial were not to get pregnant. They went into rather more detail on contraceptive technologies than was deemed suitable for consumption in Catholic institutions – it was all largely theoretical as patients with advanced cancer are most unlikely to get pregnant anyway.

"The effect was that in one hospital for one year it was impossible to open a cancer research trial. The mechanism used was not strictly legal – an extra level of philosophical and doctrinal oversight was imposed on the existing, proper state-regulated mechanism for approving trials."

Because he has been so prominent in his criticism of the government and of hospital administration, Crown has never been appointed to any official commissions on healthcare reform – he is not, he says, "well got" with the people who make those kinds of decisions. He does, however, have a vision for the future – both of his own hospital and the Irish health service.

"In my ideal world UCD would take over this hospital as a university medical centre. They would appoint a board, a secular one paying respect to the religious traditions that founded it. Its remit would have enlightenment values and be rigorously academic, though not in the sense of being anti-patient – academia and medicine would co-exist.

"It would be no less humane but would be more enquiring and inquisitive. There would be academic heads of medicine and surgery that could be hired and fired and the head of the hospital would exist at the pleasure of board. There would be a chief doctor chosen because he or she has excelled in their field and, with no disrespect intended, not because they are a great administrator – they should be the best doctor in the place."

On a national level, Crown believes that it is not too late for the Irish health service.

"If I was the minister," he says, playing fantasy politics, "and had the full support of cabinet, and the necessary legislation could be passed, it would take a year to get things into reasonable shape. Hospitals would have to take everyone. The plans for co-located hospitals would be stopped immediately because they wouldn't make any sense."

Despite Crown's successes with his patients and his research activities (he is most proud, he says, of his work with the Irish Clinical Oncology Research Group, of which he is one of the founders) I'm guessing that operating at what must in professional terms be a remove from the centre of the action when he thinks and sounds so American must sometimes be frustrating.

Although he claims to be unsuited for the 'parish-pump' style of Irish politics, I wonder if perhaps he might emerge as the visionary behind a new model for the Irish health service under a Fine Gael/Labour government – an Irish health 'czar', as it were.

"If asked," he says, "I would serve…"