Today the UK government is expected to announce that it will resume the building of nuclear power stations. This is good news for the environment. Nuclear power plants are very clean. They produce very little of the carbon dioxide that fossil fuels produce. In emissions terms, one nuclear power station replacing a conventional one is the equivalent of taking thousands of cars off the road. Almost all the waste is recycled. A well-designed nuclear plant actually releases less radioactivity into the atmosphere than a coal-fired plant.
The bad news is it will take several years to get them up and running, and in the meantime Britain is increasingly dependent on foreign gas supplies. There could well be an energy crunch before the new plant is ready to take the strain.
So the question is: why has the government allowed this to happen. And the answer is: a bit of political ideology and a lot of political cowardice. Nuclear plants produce over a fifth of the UK's electricity, but many are getting old and inefficient. So they are being shut down, and by 2023 - under the policy up until now - only 4% of the UK's electricity would come from nuclear energy. Any sensible approach would have had new building programmes in place so that the power would be there long before the lights start going out.
But this is politics. Energy ministers like Michael Meacher were delighted to consign nuclear energy to oblivion: they hate it just as they hate nuclear weapons, and they loved the thought of wind and wave power doing the job instead. Which it can't.
The political cowardice stems mostly from planning. Politicians fear that local people would object to new nuclear stations being built on their nice coastlines. Maybe they would. But the fact is that nuclear stations have a great deal of support from places that already have them, where they provide much-needed jobs. So rebuild and refurbishment on the same sites would not have been unpopular.
Now, however, the damage has been done. If the global warming scaremongers are right, maybe by 2015 we'll all be sweltering on a Cambridge beach rather than turning up the heating, so there won't be an energy crisis. But I'm not so sure.