A national energy policy must rest on three unshakeable pillars: diversity, security and cost. None of these pillars is as firm as it was. Britain’s “dash for gas”, the virtual death of the domestic coal industry and the planned closure of ageing nuclear power stations have skewed the balance. Security is threatened by growing reliance on imports from countries where wars, turmoil or the use of energy for political ends are leading to unpredictable supplies. And the rapidly changing balance between imported gas and oil in China, and in Britain itself, will inevitably mean price rises. Meanwhile, the new technology that is bringing down the price of nuclear as well as renewable energy means that long-term costs are difficult to calculate accurately.

There is, therefore, every reason why a comprehensive energy review is needed. It should focus on the expensive pledge to cut carbon emissions, the global surge in oil prices, the rapid depletion of North Sea gas and the looming “energy gap” resulting from a future demand for electricity greater than the projected generating capacity. All this, however, has been overshadowed. Instead, the review is in danger of becoming a noisy and simplistic argument over nuclear power.

The fault lies partly with the Prime Minister. His recent declaration that nuclear was “back with a vengeance” was an honest recognition of its rapidly changing balance of benefit. But it appeared to pre-empt the results of the review published yesterday, as well as goading the passionate anti- nuclear lobby. As a result, the energy debate threatens to be caricatured as a simple clash between idealistic but impractical environmentalists and hard-headed pro-nuclear lobbyists.

There is no doubt that nuclear must have a place in the energy mix. There are much rehearsed arguments against nuclear power: long-term radiation threats; vulnerability to terrorist attack; clean-up costs and high operating charges. Improved technology, in-built security systems and safer plans for waste disposal have left only the question of whether future power stations can operate economically without government subsidy. They can, and that will be more obvious as other sources become even more expensive.

The issue is critical. Planned decommissioning will bring nuclear’s share of electricity generation down to only 6 per cent by 2025; even the proposed building of six new power stations — to be built on existing sites — will still leave their future share lower than today’s 20 per cent. But whatever the energy savings and greater efficiency, alternative sources such as wind, wave or biomass, all important, will never make up the difference in an industrial society where the only safe prediction is that demand will increase.

This does not mean that the environmentalists are not right to press the case for energy efficiency. This is essential, whatever the generating capacity. Japan has shown that an industrial society can take conservation seriously, and the Government must now focus on aggressively cutting waste. It should also underpin technological innovation in fuel cells, energy storage and distribution networks. There must also be flexibility in thinking beyond the present, centralised grid with its large but often wasteful distribution system. Is there a place for microgeneration, using combined heat and power plants? The energy debate goes far beyond the narrow but emotional issue of nuclear power.