A union has warned the Chancellor against making cuts to the Sellafield nuclear site ahead of Wednesday’s Budget.

The GMB sent a letter to Rachel Reeves arguing that any potential cuts to the country’s nuclear estate would lead to fewer resources for “maintenance, monitoring and emergency preparedness” at Sellafield in Cumbria, increasing the risk of a “serious incident “.

A spokesman for Sellafield and the Nuclear Decommissioning Authority (NDA) said it was “working closely” with the Treasury.

The Treasury has been contacted for comment.

Last week, the spending watchdog, the National Audit Office, said the site was not “value for money” and spent £1.9 billion more than it earned in 2023-24.

Around 11,500 people work at the Sellafield site.

In its letter, the GMB said any cuts would reduce the number of staff available to “carry out critical safety-related tasks”.

He also said that cuts to new technology and infrastructure at the plant could slow disposal of “legacy waste”.

Sellafield said it was working to “further improve safety performance”.

The GMB said “a safety incident at Sellafield could have devastating consequences”, adding: “The economic damage of such an event would be incalculable.”

“The potential risks of reduced safety standards far outweigh any short-term financial savings resulting from funding cuts,” the document said.

A spokesman for Sellafield and the NDA said it would always prioritize “the safety and security of our employees, sites and communities as we deliver our important national mission”.

Reeves previously warned the budget, Labour’s first for 14 years, would involve “difficult decisions” and government sources told the BBC it could involve tax rises and spending cuts of up to £40bn.

Ahead of the election, Labor said it would end a “decade of divisiveness” in which the Conservatives “walked away from decisions on nuclear power” and would “ensure the long-term security of the sector by extending the life of existing plants”. .