THE risk of power blackouts in the UK within 18 months has trebled since a year ago, according to energy regulator Ofgem.

It believes the UK has failed to build enough new wind farms and nuclear powers stations to replace old fossil fuel plants, meaning electricty power capacity could fall to 2% in 2015.

It now believes the risk of blackouts in 2015 has trebled from one-in-12 it estimated in October to one-in-four, if energy demand remains at current levels. More investment in power generation and other action was needed to protect consumers, Ofgem said.

Ed Davey, the energy secretary, said he was putting in place measures to counter the threat, but admitted: "Without timely action there would be risks to security of supply. If we didn't do anything, if we allowed this supply crunch to happen, we would see spikes in power prices and that would be damaging for the consumer."

The problem is the result of forcing old coal and oil plants to switch off in favour of wind farms and nuclear plants. To counter the problems, the National Grid could ask businesses to cut their electricity use at peak times.

Ofgem said the findings showed the need for "timely implementation of the Department of Energy and Climate Change's capacity market".