Lord Lawson of Blaby of the House of Lords’ Economic Affairs committee criticised the government’s energy policy in an interview with The Times, saying that the coalition is misguided on energy and ‘doesn’t have an energy policy’ at all.

An opinion piece published in The Times on 13 May expanded on the criticism, saying: ‘What passes for a coalition energy policy is in fact a tangle of regulations, subsidies and incentives that is delaying investment, driving up prices over the long term and making blackouts a real possibility by as soon as next year.’

Davey responded to the opinion piece with an open letter, saying: ‘We’ve attracted £45 billion of investment since 2010, alongside introducing the most sweeping reforms of the energy sector in decades.’

The Times’ opinion piece quoted estimates from energy regulator Ofgem and others, suggesting that the UK must invest between £100 and £200 billion in new generating capacity and ‘smart grid’ technology by 2030 to keep the lights on, and said: ‘[The coalition] has sown confusion with its varying commitment to expensive renewables subsidies, which have a direct effect on household bills but also on industry’s appetite for investment in new gas-powered generating capacity.

‘It has given the Competition and Markets Authority far too long (two years) to report on the pricing strategies of the big six domestic energy suppliers. Above all, it has failed to recognise the potential of shale gas.’

Davey responded: ‘We have announced plans for the first new nuclear power station in a generation, doubled the amount of electricity we get from renewables, we have Europe’s leading carbon capture and storage projects, we are fast-tracking plans to maximise North Sea oil and gas, and we’re supporting the domestic shale gas sector.’