Instead of depictions of awesome power destroying civilisation, radiation generates discussion around images of contaminated food and workers in protective clothing pointing Geiger counters at children’s thyroid glands. This is the backdrop to an endless recital of a litany about cancer, radiation sickness, corrupt energy companies and their political servants, and which scientists we should trust.

You might think, then, that when ‘levels of radiation’ turn out to be infinitesimally small, morbid speculation and radiophobia might cease. Last week, a press release from the UK’s Health Protection Agency (HPA) announced that ‘the minutest traces of iodine-131 associated with events at the Fukushima nuclear facility’ had been detected in Glasgow and Oxfordshire, but that there was no risk to health. Rather than offering a sober perspective on risk, however, the finding provoked yet more speculation from the media, activists and politicians.

‘“Fukushima nuclear plant” radiation found at UK sites’, saidthe BBC. Beneath the attention-grabbing headline, however, the claim is given statistical perspective: ‘a child’s exposure in one day would be less than one ten-thousandth of what they would receive from naturally occurring background radiation in a day’. In other words, during a normal day, an individual is exposed to background radiation equivalent to nearly 30 years of exposure to the additional radiation from Fukushima now ‘found at UK sites’. The HPA press release indicated that there was no risk to human health, and the article correctly quoted the HPA, yet its author found it necessary to talk about the accumulation of radioactive substances in the thyroid gland, leading to cancer. The attempt to put risk into numerical context is defeated by such emphasis on the danger of vastly greater concentrations of the substance. It’s less rational than talking about the risks of drowning in an article about the accidental spillage of a glass of water.

‘Fukushima radiation from Japan’s stricken plant detected across UK’, reported the Guardian, followed by a half-hearted attempt to emphasise the HPA’s advice that there was no risk present to human health. This included repeating the HPA’s ‘warning’ that ‘radiation levels in the UK could rise’. However, it’s hard to construe as a ‘warning’ the advice that even raised levels ‘will be significantly below any level that could cause harm to public health’. This was followed by a story that Alex Salmond, the Scottish first minister, had claimed that the HPA had delayed publishing their advice in order to prevent causing embarrassment to the Smith School of Enterprise and the Environment – headed by erstwhile chief scientific adviser to the UK government, Sir David King – which was due to make a public call for investment in nuclear energy.

King once remarked that ‘climate change poses a bigger threat than terrorism’, that it is the ‘biggest challenge our civilisation has ever had’, and that foreign spies and US energy interests were behind attempts to undermine public confidence in climate science and the attempt to build an international agreement at Copenhagen. There is something almost comic and farcical to the way in which King and the Smith School now seem to be hoist by their own nuclear petard. The alarm they have helped to unleash in the climate debate has breached its containment, and now threatens to contaminate their own project. Because, once you speculate about energy companies’ clandestine lobbying effort and their influence over the political agenda in the face of a looming catastrophe – as King has – it’s difficult to claim that another mode of producing energy offers a panacea. The price of the politics of fear is the trust in public institutions of all kinds and their advice, be they corporations, scientific bodies and advisers, independent regulatory authorities, government departments, and politicians.

Salmond is wrong, of course. Delaying the publication of the HPA’s advice that the putative ‘fallout’ from Fukushima presented no risk could serve no purpose. Unless, that is, Salmond calculated that radiophobia would not be mediated by the HPA’s assurances, and would thus create an opportunity to put distance between his own party, with its renewable energy and emphatically anti-nuclear policies, and the apparently ‘pro-nuclear’ Labour Party at the upcoming elections.

If that’s the calculation that Salmond made, then he was absolutely correct. Writing in the Guardian, John Vidal quotes a former scientific adviser to Gorbachev during the Chernobyl accident: ‘When you hear “no immediate danger” [from nuclear radiation] then you should run away as far and as fast as you can.’ The accident at Fukushima is ‘potentially worse’ than the accident at Chernobyl, claims Vidal, while complaining that his erstwhile green comrades have compared those who question nuclear safety to ‘climate change deniers’. Ultimately, however, the question for Vidal is ‘who can we trust?’

The ‘levels of radiation’, are, after all, not the issue. It doesn’t matter that public health agencies have attempted to reassure the public that these levels are insignificant. In such a febrile atmosphere, the very fact that such a statement was made at all seems to let the safety cat out of the nuclear bag; in the minds of anti-nuclear campaigners and politicians, declaring that Fukushima has had no negative impact on the UK identifies the HPA as partial, rather than independent. Any attempt to put perspective on the magnitude of the accident is to be seen to take sides.

From any rational perspective, the quantities of radioactive material found in the UK from Japan are not worthy of comment, except perhaps to those who take an interest in the design of incredibly sensitive radiological monitoring hardware. A spokesperson from the HPA confirmed that the quantities involved were ‘at the limits of detection’. But that being the case, why would an agency concerned with public health make a statement about something that is of no concern to public health? There was a ‘lot of [public] interest about whether the radiation had reached the UK yet’, he told me, ‘we had found a result, and felt that we should publish it’.

There really was no story. So why the headlines? Why the discussion about cancer, and the danger of nuclear power? And indeed, why the coverage at all? It was not the discovery of a risk to health that led to the HPA issuing its statement, but the perception that there was an appetite for information. The information, rather than offering reassurance, seemed instead to offer an opportunity to escalate the level of alarm. It was as if policy statements and articles about ‘levels of radiation’ were written before they were measured and their significance established, with such trifling details merely tagged-on as an afterthought – a caveat, to excuse their authors from overt scaremongering.

It perhaps makes no sense to even try to quantify the risks of nuclear power while the debate is so dominated by such a disproportionate sensitivity. Thanks to the precautionary approach, the mere theoretical possibility of an accident haunts any calculation of risks. Indeed, it is anxiety itself which provides the substance of, for example, the argumentfor nuclear power from David King, the Smith School, and George Monbiot: nuclear will save us from climate change. What this anxiety speaks about is much less the merits and demerits of one form of energy production over another, and much more the inability of public figures to make arguments without recourse to fearmongering. In this environment, any argument that puts risk into statistical perspective – or criticises the alarm generated by sensational copy, anti-nuclear activists and interventions from public-health bureaucracies – looks like advocacy. And advocacy is, as Vidal and Salmond seem to have it, partial, interested, and probably gambling with public safety for profit. The only people we can trust are those who speak about the looming danger. Only crises can legitimise seemingly objective policymaking.

The expression ‘going nuclear’ used to depict the escalation of an individual’s rage, subsuming all those who stood near him or her. A more timely use of the expression might describe the absurd sensitivity to infinitesimal risks, leading to a drama that its cause did not warrant. The issue is not really what provokes the reaction, then – in this case, the non-story about almost no radioactive substance – but why that reaction is so explosive. It tears apart the relationship between radical and establishment environmentalists forged in the heat of panic about climate change. It threatens to undermine the government’s energy programme. And it turns naked fearmongering back on the fearmongerer. Suddenly, Vidal is comparing his erstwhile green comrades with ‘climate change deniers’, and Monbiot calls the UK’s first Green Party MP, Caroline Lucas, ‘wildly illogical’.

What the reaction here in the UK to events at Fukushima reveals, then, is the instability of those perspectives and the crisis-prone nature of risk-averse politics.