Somewhere in a set of committee papers I read recently, the word prevention appeared eleven times. Not once was it attached to a measurable thing that would happen, to a person it would happen to, or to a number that would tell us afterwards whether it had worked. I do not say that to be unkind about the officers who wrote it. They were reflecting the language of every strategy document handed down to them, and the language is the problem.
Prevention is the great consensus of health policy, and that is precisely why it has stopped meaning very much. Every party is for it. Every plan promises it. It has become less a policy than a mood, a way of signalling good intentions at no cost, and the reason nobody argues about it is that nobody has been asked to specify it. If Conservatives are going to make prevention our own, and I think we should, we have to do the thing the consensus never does, which is separate the prevention that works from the prevention that merely sounds virtuous.
The discipline I would apply comes from the world I spent my career in. In clinical research, nothing reaches a patient until somebody has demonstrated that it does more good than harm, and every claim gets picked apart for what the data shows rather than what everybody hoped it would show. That process is humbling in a way that health policy almost never is. Medicine's graveyard is full of interventions that were obviously going to work: hormone therapy prescribed to protect the heart, antioxidant supplements, a great deal of knee surgery. All plausible. All popular. All defeated by trials that nobody wanted to read. Policy, by contrast, is rarely made to survive that kind of scrutiny, and prevention policy least of all, because the whole appeal of prevention is that the counterfactual never arrives to embarrass you.
So what does the evidence actually support? The strongest case, by a distance, is what public health calls secondary prevention: finding disease early in people who are already developing it. Cardiovascular risk is the best example in all of medicine. Detecting and treating high blood pressure, high cholesterol and atrial fibrillation, with drugs that are decades old and cost pennies, demonstrably prevents strokes and heart attacks. And we do not do it consistently. Something close to a third of adults with hypertension in England do not know they have it, which is not a research problem or a technology problem. It is a delivery problem, and it is the least glamorous item on any prevention list. The same logic holds for picking up diabetes and its complications early, and for cancer screening where the test is genuinely good and the disease is treatable when caught.
None of that is fashionable. It will not appear in a launch photograph. It works.
Where a Conservative should be more sceptical is the register I would loosely call wellness. Population-wide behaviour change campaigns have a patchy and inconsistent record, and the honest reading of the literature is that they achieve less than their budgets imply. Screening whole healthy populations for conditions where the test is imperfect or the disease is untreatable can do net harm through false alarms, unnecessary biopsies and overdiagnosis. South Korea's experience with thyroid ultrasound is the case study every policymaker should be made to read: detected cancers rose by an order of magnitude, thousands of thyroids came out, and the death rate from thyroid cancer did not move. And a good deal of what is announced as preventive spending is simply spending with a preventive label on it and no mechanism to establish that it prevented anything. Telling those categories apart is the whole intellectual task. It ought to suit us, since we claim to be the people who ask what works rather than what sounds compassionate.
Now the part our side is better placed to say than the other, and should therefore say. Prevention does not always save money. Some of it does, particularly the cardiovascular and diabetes work. A lot of it costs money and improves lives, which is a perfectly respectable reason to fund something and an entirely different argument from the one ministers of all parties keep making. The claim that prevention pays for itself is usually overstated, and a policy built on a false economic promise gets cut the moment the promise fails to appear in the accounts. I would rather defend a programme on the grounds that it lets people live longer and better, and win that argument honestly, than smuggle it through on a business case that does not survive contact with the Treasury.
There is also a structural point, and it is the one I have come to care about most since sitting on a health select committee. Prevention rarely happens because the system is built to react. The money, the incentives and the professional prestige all sit at the acute end, and no amount of exhortation moves them. You do not get a preventive health service by asking a reactive one nicely.
What that argument usually misses is that a great deal of prevention is not the NHS's job at all. It is licensing, housing standards, air quality, leisure provision, health visiting, sexual health, smoking cessation, and it sits with councils, whose public health grant has been squeezed harder in real terms than almost any other line they hold. As a trustee of a Citizens Advice office I see the consequence from the other end, in people who come in about a damp flat and mention, halfway through, the chest condition it has given their child. That is prevention. It is being delivered, badly and expensively, by the wrong part of the state at the wrong point in the story, and the acute bill lands somewhere else entirely, which is exactly why nobody has an incentive to fix it.
So my proposal is easy to state and demanding to follow. Build the agenda on the interventions with the strongest evidence, and say plainly that this is why they were chosen. Be publicly sceptical of the ones sold on intuition, even when the scepticism is unpopular. Tell the truth about which prevention saves money and which improves lives, and defend both on their real merits. And treat the structural incentives as the actual obstacle, including the ones that sit between the health service and the town hall, because that is where the work is.
I am not certain this is the version of prevention that wins an argument in a television studio. It is duller than the alternative and it involves telling people that some cherished things do not work. But it is the version a scientist could defend under cross-examination, and it is the version that would still be standing in five years, which is more than can be said for the warm consensus it would replace.
I write here in a personal and council capacity. I have worked in pharmaceutical drug development and in clinical diagnostics, sectors with a commercial interest in early detection and in the medicines discussed above, and readers should weigh what follows accordingly.