Nuclear is a tried, tested and failed technology. New nuclear would be economically foolhardy, environmentally irresponsible, and pose long-term security questions that are impossible to address.

Investors have taken a shrewd view of the risk, and have decided not to build. Not a single nuclear reactor has been built anywhere in the world since Chernobyl in 1986 without lashings of government subsidy. Even the Finnish reactor – much touted by the prime minister – has a guaranteed price for its output and a taxpayer commitment to deal with all waste after 60 years and with any overrun costs of decommissioning.

The latest estimate of the clean-up costs of retiring our existing reactors and their waste has soared to £70 billion, and will not stop there. There is still no long-term solution to nuclear waste other than burying it in the most expensive hole in the ground. And nuclear reactors are uninsurable so that there is a cap on the liability of the generator.

Nuclear technology has an unblemished record of budgetary incontinence. Not a single nuclear reactor in this country has ever been built on time or to budget. The reactor with the smallest overrun was Torness, where the excess was a confidence-sapping 35 per cent in real terms (after allowing for inflation). Nor is this a UK phenomenon: the Finnish reactor is running a year behind schedule and the World Bank will no longer lend on nuclear projects.

So what are the alternatives to nuclear? A large part of the electricity gap should be met by energy saving measures: the National Audit Office recently found that efficiency schemes cost 1.8 pence to save a kilowatt hour of electricity, cheaper than all known means of generating electricity.

Decentralised energy is already a proven technology, supplying 40 per cent of the electricity in the Netherlands. Combined heat and power is already economical for large houses, and smaller scale boilers will be on the market next year. The technical advantage is that local generation eliminates the enormous losses of wasted heat and long transmission that consume more than half the energy used in electricity generation by fossil fuels or nuclear.

Renewable sources, notably onshore wind, are increasingly attractive to investors, though many of the newer forms still require substantial subsidy to get to the scale of output where they can compete without it.

Wind projects like Airtricity – a vast offshore proposal the size of several nuclear power stations – can provide big solutions too, and these islands are ideally placed for tidal and wave power. A scheme that captures the natural energy in the Severn – the second highest tidal rise and fall in the world – could meet five to seven per cent of UK electricity needs.

If we opt for a new generation of nuclear reactors, future generations may rue the day. We will be encumbering them with high costs and enormous and unknowable liabilities. We will miss a key opportunity to pioneer a green future.

Chris Huhne is the Liberal Democrats’ environment spokesman and MP for Eastleigh.