TWO THURSDAY mornings ago one of the Someones Who Watch Over Us descended to a dungeon beneath Whitehall and assumed charge of the National Health Service’s response to the bombing of London. Plasma screens blinked with the latest figures — casualties, hospital admissions, bed tallies — while two news channels relayed impressionistic accounts of the crisis.

If a “dirty bomb” went off, the avian flu pandemic finally blew in, or a hurricane struck, Sir Liam Donaldson would be in the emergency control room of Richmond House. As England’s Chief Medical Officer, he is the head of the NHS, the Government’s senior health adviser and the patients’ rep. He is charged, in other words, with keeping us alive. His predecessor, Sir Kenneth Calman, called the job an “epicentre of stress”. Yet when Sir Liam says he loves it, he gives every impression of sincerity.

It is slightly hard imagining him strutting his stuff in mission control — but that may be because I meet him one level above the control room and it could not be more cosily civil service. On the way to his office I encounter not only the legendary Whitehall tea trolley negotiating a lift but an area called a “Tea Point”. The trolley later follows us into his office, where Sir Liam, whose name is prefaced with Professor and followed by an alphabet’s-worth of initials (26 of them), takes his coffee black with no sugar — although I suspect this is less an example to follow than a symptom of his 12-hour days and six-day weeks. He looks good on them, admittedly: a red-haired 55-year-old whose boyish face and dying-fall Yorkshire accent recall Alan Bennett.

“The emergency plans worked very well,” he says, “and there were some incredible acts of dedication. I talked to one paramedic who was one of the first responders on the scene. His job was to go down into the tunnel and start prioritising people for removal to the surface. So he wouldn’t have known whether there were any other explosive devices down there.” It is a typically self-effacing story.

Sir Liam says he is “not particularly keen on self-promotion”, but that understates the case. His entry in Who’s Who is, as I tell him, the dullest I’ve ever read, containing not even his parents’ names let alone whether he is married. He says a prison governor once told him that Who’s Who was a “burglar’s charter” and that is why he resisted posting an entry in it for so long — but even so. It turns out that his father was a health official, and that Sir Liam, having remarried ten years ago, is now on his second wife. “We have six children between us,” he owns up. The only other clues to his private enthusiasms lie on his desk: a Newcastle United figurine, a guide to France and the latest book by Malcolm Gladwell, the sociologist who wrote The Tipping Point.

He makes, he says, his share of appearances on daytime TV, but he is hardly a household name, even among doctors. Yet England’s 15th CMO since the post was established in 1858 has outlasted three health secretaries and, arguably, has wielded more influence than any of them. His advice on stem-cell research, MMR jabs and banning smoking in public places has largely become law. He has also revived the Victorian practice of making his office’s annual report on the public health, the latest of which he publishes this morning, a campaigning document.

“I did banning smoking in public places in two reports, the first one calling for it, the second one knocking down some of the economic arguments against. The reaction to the first was pretty hostile from some of the editorials, so I felt there was quite a long way to go but the mood seems to have changed since then. On obesity, calling it a time bomb was not a particularly original cliché but it seemed to roll around a bit. When you see things moving from the news pages to the features pages to the magazines, then you know that the debate is getting quite extensive.”

But what if, having given up smoking and fatty foods, we still end up in hospital? I tell him that I would now be afraid to be admitted to a NHS ward. Hospital-acquired infections, such as the MRSA superbug, affect some 100,000 people a year in England and kill thousands. “Well,” he says, “this is one important strand of the quality of care which, at the moment, is not as good as we would want. It’s come to the top of the agenda and I agree that our performance isn ’t as good as some other European countries. But I think the tide has turned on hospital infection. And to a large extent it’s been back to basics.”

The basics are basic indeed and include persuading doctors and nurses to wash their hands. Given that there is not a basin beside every hospital bed and a ward round may take in 40 patients, a bit of lateral thinking was needed. Sir Liam championed disposable alcohol rubs.

I tell him about a friend of mine who was struck down by the superbug and placed in an isolation room only to discover that his lavatory was shared by a whole ward. “Well, I think that’s a classic example of where the problem is not with the individual members of staff, but with the design of the facility.”

He’s a great believer in blaming systems rather than the individual, isn’t he? “The evidence is clear across the world that when things go wrong in health care, they go wrong because of human error. But if you think that you can solve it by eliminating human error, then you’re ignoring the real source of harm, which is the system that puts someone in circumstances where they’re more likely to make a mistake rather than less.”

Sir Liam’s secret weapon, it turns out, is us. He wants us to complain more. “I once heard Terry Leahy of Tesco saying that customer feedback was hard-wired into Tesco. I think patient feedback should be hard-wired into the NHS because it is absolutely vital. We do do it but it is not yet a strong part of the culture.”

So he welcomes informed patients who challenge their doctors? “I do. At medical conferences, the awkward bit is often question time but, quite often, an irate doctor will stand up at the back and say, ‘You’re raising patients’ expectations. Stop doing it’. And my response is that we want people to have high expectations because it’s only by stretching ourselves and being ambitious and comparing ourselves to other countries that we find ways of doing things differently.”