Taxpayers face a near £130billion bill to wind down the UK's old nuclear sites, in a blow to Energy Secretary Ed Miliband.

An investigation by the National Audit Office (NAO) reports it will cost £128.8bn to do the job, £23.5bn more than previously believed.

France's state-owned energy giant, EDF, is due to hand seven nuclear stations back to the Government for decommissioning as they close in 2028.

Sizewell B on the Suffolk coast will continue operating in the 2030s before it too will be decommissioned.

The NAO report said the current, best estimate is that the eight existing sites will cost £23.5bn to defuel and decommission, which adds to the £103.5bn pot set aside to deal with other clean up projects.

A fund set up to secure the money needed to decommission the eight nuclear stations overseen by Mr Miliband's Department for Energy Security and Net Zero (DESNZ) has proven inadequate, according to the NAO.

Taxpayers could be on the hook for even more money as costs "could rise further" if defuelling takes longer than planned, the NAO said.

Around 70 percent of the cost of cleaning up Britain's nuclear sites stem from Cumbria's Sellafield site, according to the Telegraph.

A previous NAO report identified Sellafield as the UK's "most complex and challenging nuclear site" with "highly hazardous" materials stored there from Britain's nuclear industry.

It notes that the Government regards some of Sellafield's buildings and what's housed inside them pose an "intolerable risk".

The Nuclear Decommissioning Authority (NDA) is in charge of Sellafield, with its clean up expected to take until 2125.

According to the NAO report, Sellafield has made "slower progress" in reducing site risks than it would have liked and needs to accelerate the pace at which it retrieves waste from the oldest storage facilities.

The NAO concluded in October that while management of major projects has started to improve, some are significantly over budget and behind schedule.

Meanwhile, Mr Miliband announced at the COP29 climate summit in Baku earlier this month that the UK has teamed up with the US to accelerate the deployment of "cutting edge" nuclear tech, such as small modular reactors.

The Government maintains that new nuclear will help to secure thousands of jobs, boost Britain's energy independence and support efforts to decarbonise industries, including steel and aviation.