Bruce Anderson: David Cameron was right to slap down Dan Hannan

A British politician who expressed scepticism about the NHS would be like an American politician admitting to atheism

Magna est veritas et prevalebit. In politics, that is not always true. Timing is crucial, as two Tories discovered last week. Alan Duncan was right, both about Parliament and about MPs' pay. Over the centuries, Parliament has been the great forum for national debate, and since the late 17th century, constitutional arguments have been resolved within its walls, rather than on the streets and battlefields. But Parliament's effectiveness depends on its independence and its prestige.

In recent years, both have been under threat. The power of the executive has increased, is increasing and ought to be diminished. Although this has been a problem under all recent governments, it has become much worse since 1997. Margaret Thatcher and John Major did at least respect Parliament and revere its history. They understood that its glories were part of our national glory. But the current lot have no interest in history, do not do respect and only conceal their contempt for national glory because it might cost votes.

They also distrust any institution which they cannot control. They would like to turn Parliament into a minor part of the executive, so that it became the bureau of legislative rubber-stamping, regulated by OffParl, a quango whose members would enjoy much more status than MPs.

The temporary embarrassment over MPs' expenses has given Parliament's enemies their opportunity. The danger is that in a few thoughtless and frenzied months, we will destroy a vital part of our constitutional heritage. No-one, not even Lord Rogers, would dare to propose that we demolish the building. It would be equally crazy to destroy its functions.

So Alan Duncan was right to warn of the dangers of nationalising Parliament. He was equally right about MPs' pay: or rather, Tory MPs' pay. In the early Nineties, when John Smith was irritated by some of his Labour colleagues' reluctance to face reality, he pointed out that he was one of the few Labour MPs who could earn more outside Parliament than in it. It remains true that the great majority of Labour MPs receive a salary increase when they arrive at Westminster. That has never been the case with Tories. Although things are now changing, the Tory party has traditionally recruited a lot of MPs from the City and the law: men for whom Parliament means a financial sacrifice. Outside politics, at least half of David Cameron's Shadow Cabinet would be earning at least twice their current income.

There is a further problem. Unlike Labour MPs, Tories believe in educating their children. On an MP's salary, that is hard. The squeeze on outside earnings will make it harder still. In the last few weeks, I have met two chaps in their mid-thirties who would make admirable MPs: Cabinet material in a Cameron second term. Neither could afford to consider it.

None of this will arouse widespread public sympathy. Over large swathes of the country, £64,000 a year will seem more than enough, even before the housing allowance. In licensed premises up and down the land, it is all: "snouts in the trough, what do they do for it anyway, it's disgusting when the rest of us are so hard-up." As that is the public mood, this is a time for Fabian tactics: do not give battle to superior forces, but wait for a more propitious moment. Although Mr Duncan was unlucky – he thought that he was speaking in private – Mr Cameron had no choice but to rebuke him.

The same was true over Dan Hannan's criticisms of the NHS. A man of relentless integrity, Mr Hannan is a Whips' nightmare and one of the most admirable people in public life. On health, he has a good point. As Enoch Powell pointed out in the early Sixties, the NHS is unique, in that the worse its performance, the more public sympathy it attracts and the easier it becomes to demand more money.

According to Lance Price's memoir of his time as a Downing St spin-doctor, Gordon Brown feared that the NHS could turn into a financial black hole. Mr Brown himself was not happy with the treatment he received for his eye injury, though that was many years ago. At its best, the NHS offers world-class medicine. It is not always at its best. But the NHS does have one undeniable advantage, though oddly enough no politician ever mentions it. By international standards, it is cheap.

The British health debate is not only cheap. It is positively undernourished. There is a basic absurdity. Why on earth should we talk about the National Health Service, as if the method of delivery were as important as the product? Instead, let us discuss health care. By discarding the illusion of an infallible monolith, we will have more chance of discovering what succeeds and what fails.

But Mr Hannan is right. The Americans have little to learn from us. They would be better advised to examine the French system, which in GDP terms is not much more expensive than our one and which is rated the best in the world by the World Health Organisation. More to the point, it is highly rated by those notoriously ungrateful grumblers: the French. As well as studying France, we British could try to emulate aspects of US medicine, especially the cancer survival rates. That said, there might be a problem. We could never afford the American system.

Nor can they. The future projections for health costs would make them unsustainable. Equally, it is absurd that so many Americans have to rely on hospitals for basic health care: surely there is a cheaper way? Finance ought to force a re-think of the American approach, but Mr Obama has two problems. First, he has acted without thinking. Second, he has aroused widespread doubts, and not just Sarah Palin's. Centrist voters are remembering that he was one of the most left-wing members of the Senate. There is still the suspicion that he is a closet socialist, and in America, there is little market for socialist medicine.

So Dan Hannan had a good point. David Cameron had a better one. In electoral-handicap terms, a British politician who expressed scepticism about the NHS would be like an American politician admitting to atheism. Dan Hannan is secure in the European Parliament. David Cameron is not yet securely into No. 10. Even Margaret Thatcher used to say that the NHS was safe with us (Lots of people disbelieved her, but for better or worse, so it was).

The NHS is central to the Cameron strategy of decontaminating the Tory brand. No government has ever cut health spending, and Mr Cameron intends to increase it. So why should he lay himself open to the accusation of cuts? Reforms and improvements are necessary, but the best way to approach those is to treat the NHS as a beloved Grade 1 building in need of repair. Do it gradually, so that no-one notices until the work is complete and the improvements are obvious. Never ever give the impression that you really want to pull down the building.

That is why David Cameron tried to slap down Dan Hannan. In Strasbourg, Mr Hannan can indulge a taste for intellectual speculation. In London, Mr Cameron must curb his party's taste for intellectual self-indulgence.