The clean-up of some the oldest and most contaminated nuclear sites will be completed up to 35 years earlier than proposed, saving the taxpayer billions of pounds, according to the UK Atomic Energy Authority.

Windscale, site of Britain's worst nuclear accident, is one of several facilities to benefit from the accelerated programme. This is expected to cut the bill for decommissioning former nuclear research and development sites to £4.8bn from £8.4bn.