On Thursday, Chris Huhne admitted in a speech at the Royal Society the UK government has made a consistent foul-up on nuclear energy since the 1950s. "We have made pretty much every mistake human ingenuity could devise," he said, adding "And boy, are we British inventive."

He's right: the entire thing has been a disaster. The UK now manages the world's largest plutonium stocks. That's partly because we built reactors whose primary design criterion was to give us plutonium for military purposes rather than cheap electricity. As a result, we have stockpiles that may need to be guarded for tens of thousands of years. That's quite some legacy.

Huhne admitted that half of his department's budget goes in cleaning up nuclear waste, and it will rise to two thirds next year. "That is £2 billion a year, year in and year out, that we are continuing to pay for electricity that was consumed in the fifties, sixties and seventies on a false prospectus."

No wonder he said that nuclear policy is "a runner to be the most expensive failure of post-war British policy-making, and I am aware that this is a crowded and highly-contested field."

As a result all future nuclear builds will be chosen through open competition, and will not be financed via the public purse: there will be no more secrecy and there is to be no more "Robert Maxwell style plundering of the public piggybank."

It's a lovely idea, because nuclear power is, in theory, our best hope of a low-carbon future for energy production. It's safe too, despite what you might think in the light of Chernobyl and Fukushima.

In this rosy glow, Huhne declared, "I believe that nuclear electricity can and should play a part in our energy future provided that new nuclear is built without public subsidy."

Unfortunately, it's a belief that's difficult to share. It's clear that nuclear is difficult to build safely without being almost unfathomably expensive.

The only new plants being built in Europe (at Olkiluoto, Finland, and Flamanville in northern France) are already four years behind schedule and more than 2.5 billion euros over budget.

The late delivery messes up all the finance, which means the cost of electricity will have to be prohibitively high in an open, deregulated market. These were meant to be the flagship projects for new nuclear, and they are in trouble way before anyone has plugged them in. If new UK nuclear has to be built "without public subsidy", as Huhne said, it simply won't be built.

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