But politically, shale is a long-term consideration. The politicians who now realise that their policies are inevitably inflating the cost of energy to the electorate also know that the benefits of shale probably won't be felt until 2020. Meanwhile they need to respond to the general disenchantment both with competitive markets and with renewable subsidies.

On the Left, many are calling for a partial renationalisation, certainly at retail level. They argue that as there is little to choose between energy retailers, whom they accuse also of price-gouging, it would be better to have one publicly owned retail electricity agency, with a monopsony in the wholesale market and a monopoly in retail.

The Tories are in disarray. On October 23, David Cameron told the Commons that he would like to scale back some of the subsidies. That will prove difficult while he is in harness with the Liberal Democrats.

The fundamental problem is the commitment, made by the last Labour government and restated by the Coalition, to derive 20 per cent of total energy and 30 per cent of electricity from renewable sources by 2020. Cameron seems to have neither the philosophical inclination nor the political courage to offer the electorate the possibility of scaling down or removing those objectives after the next election. But without cheap energy, he cannot win.