The Government has failed to improve the nation’s energy efficiency as more than half of Britain’s 27 million homes are still not properly insulated, it was claimed today.

Consumer body Which? has criticised the UK’s energy efficiency policies, claiming these could cost customers £8.4 billion by 2015.

Its new report suggests the Carbon Emissions Reduction Target (CERT), which ran from 2008 to 2012, cost consumers £5.5 billion while the Energy Company Obligation (ECO) which runs until 2015 could cost £2.9 billion in total.

Despite the huge price tag, the consumer group claims the schemes are not working and wants a “radical overhaul” of policies.

Executive Director Richard Lloyd said: “We’re calling on the Chancellor to use his Autumn Statement to take action by cutting the cost of Government energy policies down to size.”

The call comes as new statistics showed there were an extra 31,100 winter deaths in England and Wales last year, with nearly a hundred protestors in London demanding the Government renationalise UK energy companies.

Which? is also urging the Government to prioritise low-cost energy saving measures rather than expensive ones such as solid wall insulation, which could cost as much as £10,000. It claims this could save between £242 million to £363 million a year while “helping at least the same number of households and still meeting carbon targets”.

A DECC spokesperson said: “The Government is looking closely at the impact of green levies on consumer bills and how the measures they support are paid for. Details of the review will conclude shortly.”