Business secretary Vince Cable announced this week that he wants to "ration" British science, potentially eliminating the 46% of UK research that is not defined as world class. My immediate reaction was: you must be crazy.

Cable's narrow interpretation of quality is an astonishing insult to the thousands of British scientists who help this country (and its ministers) have a well above average reputation and global influence. Cable didn't mention that most of the 46% he considers less worthy is actually classed (by the independently run Research Assessment Exercise) as internationally or nationally recognised for its "originality, significance, and rigour". In fact, in 2008 it found that only 2% of UK research "falls below the standard of nationally recognised work". It is this work that should be cut.

If Cable goes further, what will be the impact? The two biggest killers in Britain are heart disease and cancer. If the recognised work was eliminated, that would lead to a 40% cut in research for heart disease and a 28% cut in cancer research. Britain's ability to tackle the biggest threats to national health would be significantly disabled.

Cable acknowledged that investing in science is critical to economic performance. He cited OECD evidence showing that investment in innovative research was crucial for future economic success, and quoted the organisation's conclusion that cutting back investment in innovation "will damage the foundations of long-term growth". I couldn't have put it better myself. And, further, he pointed out that in the face of financial crisis, smart governments – such as the US and Sweden – were actually increasing investment in research.

But when he says we will "economise", to "screen out mediocrity", this is exactly what the research councils do already. The Medical Research council, for example, spent £704m in 2008/09 on research. In the past year, 1,475 research grant applications were made to the council, but only 279 were funded. The research councils ensure that taxpayers' money is spent only on the best research, with the potentially highest impact on improving human health and welfare.

Of course, there is waste in science. In medical research, for example, Iain Chalmers and Paul Glasziou from Oxford have argued that sometimes the wrong questions are asked by scientists, poor experimental designs are used, studies remain unreported, and those that are published are incomplete. But it's not a matter of cutting research. It's a matter of improving it. In medicine that means including patients in decisions about what questions to answer, improving the quality of research designs, and ensuring the results of research are fully and freely reported.

There is another reason to question Cable's rationing plan: his impending attack on universities. The university – the main centre for UK science – is funded from two sources: the research councils (which distribute £2.8bn annually) and the Higher Education Funding Council for England (£7.4bn). This dual funding gives universities stability. In the latest independent rankings of the world's universities, the UK is second only to the US in the quality of its education and research. This week, Cambridge beat Harvard to first place in one important league table. Yet it is the depth and breadth of our university sector that is extraordinary. The UK had 30 of the 200 best universities in the world. For a small nation of just 62 million people, that is extraordinary: Germany had 12 places, Japan 10 places.

Does this success mean that we can safely trim a little fat from our science budget? No. The Shanghai Jiao Tong ranking system, which is especially sensitive to success in the sciences – reveals that Asia, and especially China, is rapidly catching up with western centres of excellence. Cable pointed out this week that China has increased government funds for science by 25%. Any deceleration in UK investment will inevitably diminish our relative success against a major competitor.

Cable says the government's spending priorities "will help to define what we value as a nation". One of Britain's last remaining comparative advantages in the world is its science, and the universities which support that science. It's hard to believe that intelligent ministers who understand the arguments for science are going to preside over cuts that could not only set UK science back a generation, but also inflict a needless wound on our physical, mental, social and economic health. But that is what Cable has prepared us for.

Richard Horton is editor of the Lancet