The relationship between science and politics has been likened to a marriage1, with the inference being that, to develop, the partners must not become alike but must respect their differences — and that the odd quarrel along the way is no big deal. Recently, however, science has taken the role of the meek, misunderstood spouse that has little influence over their all-powerful partner. Science must become stronger in this relationship; at present it does not have the respect it deserves from most politicians, and so its champions must become louder within the political arena if we are to address the grand challenges of the coming century.

Two recent incidents in the UK suggest that scientists hold little political power, with the real crux of the matter being a lack of science-literate politicians. Although some prominent politicians have science backgrounds (Margaret Thatcher and Angela Merkel were chemists) out of the 650 (pre-2010 election) UK members of parliament (MPs), 27 held science degrees and 584 admitted to having no political interest in science and technology — and taking into account upcoming retirements, it's about to get worse2. This alarming finding calls into question whether the people responsible for making important policy decisions, either based on scientific research or about its funding, fully understand its importance or crucially the scientific method at its core.

The scientific method relies on the search for and critical consideration of evidence on which to base explanations and decisions, but it is often trumped by political or economic considerations, or more worryingly, is just not understood. Although UK government policy may be more informed by evidence than in the past, the way in which hard scientific evidence is handled and debated often seems to result in two steps forward and one step back. Take for example the way in which a frightening number of UK MPs have reacted to a recent government report on homeopathy — a practice currently funded publicly by the National Health Service.

In a progressive move, a science and technology committee, made up of the UK's more science-minded MPs, was tasked to look at the supporting evidence for homeopathy to help re-evaluate government policy. The thorough, evidence-led report, found that “homeopathy is not efficacious (that is, it does not work beyond the placebo effect) and that explanations for why homeopathy would work are scientifically implausible”. The committee therefore recommended the withdrawal of funding. On publication of the report, MP David Tredinnick — also an advocate of unscientific practices such as 'medical astrology' and 'remote energetic healing' — spearheaded a movement to reject the findings. Even though the rigours of the scientific method are there to behold in this report — which dismisses outright the value of homeopathy — 70 MPs supported Tredinnick's campaign.

Science has fought back in the form of science writer, Michael Brooks. He took the view that if our politicians don't listen to rational, reasoned arguments he would change things by trying to become one of them, standing against Tredinnick as a candidate in the recent 2010 election3. Although ultimately unsuccessful, this unusual move has gone some way to raising the profile of science.

The case of homeopathy is just one extreme example of how politicians can harm the development of science by undermining and questioning its credibility. Further troubles undoubtedly lie ahead because so many of the challenges faced by society today rely on knowledge afforded through scientific research, in topics far more complicated and with greater ramifications than homeopathy: climate change, energy provision and genetic modification to name but a few. To deal with them ably, governments must become more science-literate. This doesn't require our politicians to be scientists (although this would help), rather they must have an appreciation of science. Foremost, however, they must learn how scientific research actually works to reach the best possible explanation for a given set of hypotheses.

There are obviously no expectations that politicians must be experts in cutting-edge science — any government must also have professional science advisers who present evidence around which policy can be moulded. Again, however, the UK government has shown how, even on the most scientific of subjects where expert testimony is of paramount importance, their policies can be chosen without full regard for the evidence with which they are provided, as in the case of Professor David Nutt, the government's former chief drug adviser.

In the first of a series of spats over Nutt contradicting the government's hard line on illegal drugs, it reprimanded him for his efforts to show how the harm drugs can cause compares with other potentially harmful activities — for example, he highlighted that horse riding was statistically riskier than using the drug ecstasy. Then, after ignoring his advice to not reclassify cannabis from class C to B, it later sacked him for publicly presenting evidence suggesting that LSD, ecstasy and cannabis were in fact less harmful than alcohol and tobacco — again contradicting the government's stance. Although the issues involved in the classification of illegal drugs are not clear cut, and governments must balance many different factors, ignoring expert advice and attempting to silence its communication to the public — rather than explaining their decisions in the face of it — undermines science and its worth.

Winston Churchill once said that “courage is what it takes to stand up and speak; courage is also what it takes to sit down and listen”. Science needs courage. It needs courage from scientists like David Nutt and Michael Brooks to stand up and speak out assertively to communicate its importance to politicians and to not back down when the evidence is clear. Scientists must question policies that ignore the evidence and must try to educate those who make them. In return, we need courage from governments and politicians. Governments must try to teach their members more about the basics and value of science so that policy decisions can be informed by a greater understanding of the technical issues. Politicians should seek advice from scientists and be open to learning more about what may seem like difficult topics. They must be willing to trust the scientific method and, in doing so, make tough decisions that not only consider the political ramifications, but take into account the underlying evidence.