According to a leaked document from Downing Street, green taxes could cost families an extra £300 a year which would be an extra 30% by 2020.

The note which was written by Ben Moxham, Prime Minister’s senior policy adviser, also question Chris Huhne’s believe that prices would be kept low because of energy efficiency.

Over time it is clear that the impact of our policies on consumer bills will become significantly greater,” Mr Moxham states.