In a pool of cold water in west Cumbria sit hundreds of metal flasks, silently oozing heat. Each contains enriched uranium removed from the reactors of nuclear power stations after use. It remains highly radioactive. Exposure to the contents of one flask would be followed quickly by death.
There are 2,000 cubic metres of high-radiation nuclear waste in Britain, some kept in cooling pools near reactors but most stored at Sellafield. A terrorist attack here would be a disaster to dwarf the meltdown at Chernobyl two decades ago, says the campaign group Greenpeace. Two million people could die.
Some people say this deadly waste should be fired into space. Others say bury it deep underground and wait tens of thousands of years for its radioactive strength to decay. But the people who matter, the ones who stop it from leaking and killing people, are waiting for the Government to tell them what to do.
Or they were, before the rules changed. The Prime Minister surprised the nuclear industry last week by saying that its form of energy - underfunded for years, feared by many - was "back on the agenda with a vengeance". Suddenly it is assumed that a new generation of reactors will be built to replace the existing ones that are being prepared for shutdown. There now seems no need to wait for the energy review due to be published in July. Nuclear enthusiasts are glowing with pleasure.
But more power means more waste. Even if none of the expected 10 new power stations is built, this country will still produce enough highly radioactive nuclear waste to fill 14 Olympic swimming pools.
"For 50 years the UK has been creating radioactive waste without any clear idea of what to do with it," says Professor Gordon MacKerron, chair of the expert Committee on Radioactive Waste Management, which will also report in July. "Whether we like it or not, waste exists and we have to deal with it."
Only now the problem is even more pressing. Mr Blair can hardly declare a new nuclear dawn without saying where the waste will go. Investors - along with many of his own MPs and even ministers - wait to be convinced.
Two-thirds of the existing fuel is being kept in steel-lined, concrete-encased cooling pools until it can be treated. This means pouring it with molten glass into steel containers to cool and solidify. These canisters are kept in concrete storehouses. They have higher radiation levels than the old reactor parts and nuclear sludge that make up what is called intermediate-level waste. It is still very dangerous, so robotic arms pour on concrete and seal it in vaults. There will be 350,000 cubic metres of this stuff (or 116 swimming pools) even if all but one of the existing power stations are closed down by 2023 as expected and no more built.
Then there are the 75,000 cubic metres of uranium which potentially could be used in another reactor. And 4,300 cubic metres of plutonium sitting in storage waiting to be recycled. Or blown up. Or stolen and used to construct devastating bombs.
The solution is to bury it all half a mile underground, according to Professor MacKerron's committee. This is already being done in Finland, where they are building a pressurised water reactor that is likely to be a model for the new ones in Britain. Canisters will be transported to tunnels deep underground and buried even deeper in holes filled with clay.
But building such a subterranean site would take years, not least because of planning permission. Would you like it where you live? And that is also the problem with the new power stations. Sizewell B, the last to be built, was held up by planning inquiries lasting six years. The companies that will compete for permission to build its successors responded to Mr Blair's words by pleading with the Government to cut the red tape. Nobody will want to invest unless they are sure the project can be finished on time, they said. And the precedents are terrible. "The UK has never built a nuclear power station on schedule or within budget," says Walt Patterson, associate fellow in energy and the environment at the Royal Institute of International Affairs.
The cost of the first is estimated at £2bn and it will take 10 years to put up even if the builders work like the clappers and the Government finds a way to ignore all those pesky protests and legal challenges. To build 10 will take at least two decades. But critics say that blows a hole in Mr Blair's argument for having them. The severe energy shortage that Britain is facing will occur in the next 10 to 15 years. Environmentalists say spending the same billions on the speedier (and cheaper) harnessing of renewable sources such as wind would be better.
The problem Mr Blair set out for the Confederation of British Industry last Tuesday is that North Sea gas is dwindling and supplies from elsewhere are pricey and unstable. The nation is also falling way behind on its targets for cutting carbon dioxide emissions. "These facts put the replacement of nuclear power stations, a big push on renewable and a step change on energy efficiency, engaging both business and consumers, back on the agenda with a vengeance," the Prime Minister said.
Keith Parker heard the news on his car radio. "I was surprised," says the chief executive of the Nuclear Industry Association, which represents the groups involved in building and maintaining reactors, "but there is nothing we can do about it until we see the fine detail."
Ten more will produce only 10 per cent more waste, he says. But how would the man from the NIA feel if all Britain's nuclear doings were buried near his house? "Clapham Common is the nearest green field," he says, smiling uneasily. "I don't think I would have too much concern." Not too much? "You always have some concern about any large industrial facility being built near you. I might have concern about the effect on property prices." That is disingenuous. "I don't think I'd have a concern about safety."
Nuclear power stations work by splitting the atoms of enriched uranium. If the atoms split slowly, in a controlled chain reaction, you have a powerful source of energy. If they split quickly you have a bomb. Twenty years ago the reaction inside the Soviet power plant at Chernobyl was allowed to race out of control, creating the worst nuclear disaster in history. It is now estimated to have caused 100,000 deaths. British land is still contaminated and children here have cancer as a result of the fallout. Elena was five years old and lived close to the reactor. She remembers the clouds darkening, the wind blowing and a few drops of rain beginning to fall. "It was only later we found out that the rain was radioactive." So was the water in the river where they played, and the mushrooms they liked to eat from the forest. Both she and her sister spent their teenage years fighting brain cancer that nearly killed them. These days she campaigns against nuclear energy with Greenpeace. "Chernobyl poisoned my youth."
Such a tragedy "just couldn't happen here", says Keith Parker of the NIA. "The design at Chernobyl would not have been licensed." Modern systems shut themselves down if there is a problem. Still, it is hard to shake off Elena's story on the drive south, down to the coast.
There the sky is on fire, the sunset apocalyptic. The wind is racing in from the sea over a wide expanse of sandy, grassy shingle, clacking ropes against the masts of a few beached boats. The scattered huts and low clapboard homes that seem to perch on the shore waiting to be swept away could be on a remote spit in New England, but Dungeness is in Kent, beyond the marshes. France is out there somewhere, through the sea mist.
Turn to face the west and the scene changes in a breathtaking way. Behind the silhouette of the old lighthouse looms a sight as alien and shocking as a spacecraft: a huge grey-green shadow of a building bigger than several tower blocks. Pipes crawl over its surface; clouds of steam leak through the walls. As the darkness deepens this windowless building begins to glow with pulses of golden light. Now you notice the noise: a perpetual high-pitched metallic whine, and also the sound of air under pressure like the jets of an airliner preparing to taxi.
"Sometimes," says Joe Thomas, a fisherman who grew up here, "it sounds like a kettle boiling." Dungeness B, the second plant on the site, has been supplying the National Grid with electricity since 1983. British Energy announced last year that its life would be extended to 2018. This was greeted as good news by locals, not least because the plant provides 550 full-time jobs.
People living within a mile of it have have been issued with potassium iodate pills to take in the case of a nuclear emergency, but Louisa Whenday of the Dungeness Residents' Association says: "Most people aren't worried [about safety] because you wouldn't move here if you were." She told the BBC: "I find it no threat at all. The greatest fear for us is terrorism but even that would take something really big, much bigger than an aeroplane or a bomb. To be honest, everyone is so used to seeing it that they'd miss it. I think it's really quite gorgeous, especially at night when it's lit up. It looks like a ship at sea."
Signs warn that "the wildlife of the shingle is extremely rare and easily damaged". There are 600 plants growing among the pebbles, including sea kale and lichens on dwarf blackthorn "only found at Dungeness".
Roger Higman of Friends of the Earth says: "The English Channel is washing away the peninsula the power station sits on. It was a stupid site for a power station in the first place."
The eerie, isolated atmosphere is part of what made it attractive to the late film director Derek Jarman. Visitors can walk from his tiny cottage right up to the concrete perimeter fence of the power station, where the only warning is "please take your rubbish home with you".
The visitor centre was shut after the 9/11 attacks. From the beach it is too easy to imagine a jet coming low over the Channel. Then Dungeness would not be a refuge from the horrors of city life; it would be hell on earth. Friends of the Earth say a direct hit from a jumbo would cause a disaster 40 times worse than Chernobyl.
Nuclear power stations were designed to withstand such an accident even before 11 September, protested Keith Parker back at the NIA in London. "The studies that have been done show that the jet would vaporise. In terms of physical damage to the reactor there would be very little. And there would not be the release of radiation."
Whatever Mr Blair says, it will take time to overcome the legacy of safety scares and sci-fi thrillers, overspends and environmental fears. "It's not going to happen unless we have public support," says Mr Parker. "But if you put the proposition 'Would you support nuclear as part of a mix, with renewables?' then 60 per cent of people say yes."
The residents of Dungeness would, it seems. But to stand in the half-light looking up at the vast power plant is to remember that for many people the nuclear debate is settled in the pit of the stomach. So which do you instinctively fear more: global warming or radiation poisoning? Either way, from here on the shingle the future looks, and feels, quite frightening.
How a nuclear power station works
1. The reactor core produces heat. It contains hundreds of fuel rods, metal tubes filled with ceramic pellets. Inside each of these is uranium enriched for high concentrations of the atom U-235. The atoms split, throwing off neutrons at 10,000 miles per second, creating a chain reaction.
2. Control rods slow down the reaction. They are made of cadmium or boron and are lowered into the reactor core to absorb some of the neutrons being released, reducing the heat to the required levels. This process is also moderated by water.
3. The water is pressurised. It is pumped in a closed loop around the system at a very high pressure so that it will not boil even at 300C. It cools the core and helps to slow the nuclear reaction.
4. The flowing water carries heat from the core to the steam generator. If the Government approves 10 new power stations, as expected, they are likely to be pressurised water reactors like this. The only one in the UK at present is Sizewell B.
5. The steam generator works like a kettle. The water heated by the core is pumped through it in a pipe. This heats up water being pumped at a lower pressure around a second circuit, which turns to steam.
6. Thick concrete encases the system. This is to prevent radiation from escaping into the environment. If something goes wrong modern power stations are designed to shut themselves down.
7. Turbines are driven by the steam. This is then cooled by yet more pipes and condenses before going back round the system. The industry says its low carbon emissions make nuclear a green option. Environmentalists say wind farms produce less CO 2 and no radioactive waste.
8. The transformer turns energy from the turbine into electricity.
This can be sent on to the National Grid. Nuclear power stations generate about 20 per cent of the UK's electricity. If no new reactors are built then the output will fall dramatically, as all but one of the sites in operation close by 2023.