There is little in the Labour Party manifesto to remind voters of Tony Blair’s conviction that Britain’s destiny is to set an example to the world on global warming. There is remarkably little said about the matter at all, given the apocalyptic view that the Prime Minister apparently takes of the impact of climate change.

There are two reasons for this unwonted reticence. The first is embarrassment. Having pledged to curb UK carbon emissions by 20 per cent of the 1990 rate in 2020, and 60 per cent within a generation — cuts far steeper than the Kyoto Protocol requires — emissions have been rising, not falling, for the past two years. There are few lamer passages in the manifesto than the statement that “our review of progress this summer will show us how to get back on track”.

The second reason is the reluctance to grasp the nuclear nettle. Labour is determined to get through this election without saying where it stands on building new nuclear power stations — one of the “greenest” energy sour-ces in climate change terms, but a dirty word with green lobbies worried about waste and potential “meltdown”. Officially, Labour stands where it did in the 2003 White Paper: ill-disposed toward nuclear power and enthusiastic about serried phalanxes of windmills, rolling miles of biomass crops and “high standards of energy efficiency”. But even if renewable energy sources are able to provide 20 per cent of Britain’s electricity by 2020, as hoped, they would merely be making up a loss of around 20 per cent in electricity supply that will be inevitable if no new nuclear reactors are built. Nuclear energy furnishes nearly a quarter of Britain’s electricity today, but most of its 12 nuclear stations are due to be decommissioned before 2020.

Science has not yet found a way to make harmless the nuclear waste whose potency lasts for centuries, not a four-year election cycle. But the new generation of pressurised water reactors produces less than a tenth of the waste created by Britain’s existing power stations. We have been living with nuclear waste for 50 years: continuing reliance on nuclear energy would add relatively little to the burden, and continuing research will surely lessen that burden. Safety-conscious countries such as Finland are commissioning new reactors and storing waste deep underground. Yet the UK continues to dither even about waste disposal, so that much of our waste sits in tanks around the country where it is more vulnerable to leaks or terrorist attack. Engineering advances also mean that fears of reactor meltdown are misplaced. A Chernobyl-style leak would apparently be impossible in the new generation of reactors, which can shut down without extra water.

The nuclear option should not be an excuse for ignoring energy efficiency or renewables. But in balancing the risks of nuclear power against the possible risks of climate change, the nuclear option does fill a yawning gap.

The problems posed by nuclear power are more political than scientific. Tim Yeo, the Conservative spokesman, has had the courage to say that, if elected, his party would take a decision on new nuclear stations within a year. If the industry could meet concerns about costs and waste disposal, building would proceeed. This is not only a wise stance: it treats voters like adults. And once the ballots have been counted, politicians will themselves have to act like adults on this question.