Sellafield cleanup cost rises to £136bn amid tensions with Treasury

National Audit Office questions value for money as predicted bill for decommissioning increases by 21bn

The cost of cleaning up Sellafield is expected to spiral to 136bn and Europe's biggest nuclear waste dump cannot show how it offers taxpayers value for money, the public spending watchdog has said.

Projects to fix buildings containing hazardous and radioactive material at the state-owned site on the Cumbrian coast are running years late and over budget. Sellafield's spending is so vast - with costs of more than 2.7bn a year - that it is causing tension with the Treasury, the report from the National Audit Office (NAO) suggests.