The top-secret Atomic Weapons Establishment was fined £1 million pounds for breaching health and safety rules which caused an employee to suffer burns.

A district judge handed down the severe punishment after hearing about an incident at the AWE base in Aldermaston, the scene of numerous nuclear protests. He also ordered to nuclear base to pay court costs of £26,000.

Prosecutor Craig Morris, representing the Office of Nuclear Regulation (ONR), told district judge Davinder Lachhar that the worker received minor burns from molten metal after working on a dangerously exposed socket on one of 19 electrical switches at the site.

Mr Morris said the accident triggered power failures in the local area, lights to go off and emergency power to activate. He explained that the accident, although minor, had followed on from another health and safety breach in 2010, for which the firm was convicted in 2013.

The AWE had failed to follow the ONR’s simplistic health and safety regulations, after the controversial weapons maker was told to cover the exposed socket with industry standard protection following an ONR inspection.

Defence counsel James Maxwell-Scott QC, told District Judge Lachhar, sitting at Reading Magistrates’ Court: “This prosecution arose out of an indictment against the Atomic Weapons Establishment brought by the Office for Nuclear Regulation.

“It does not concern an issue of nuclear safety and was an incident that could have occurred at a more commonplace organisation.

“It is an incident the defendant watches very carefully and it has taken exemplary responsibility for. Co-operation with the defendant could not have been any fuller in this case,” he said.

“There were generally effective health and safety precautions in place and the defendant was effective in employing them.”

In mitigation, Mr Maxwell-Scott also cited the small risk of exposure to electrical shock, the minor nature of the accident and injuries and the early guilty plea entered by the firm.

However, the mitigation was not enough to influence District Judge Lachhar, who imposed one of the biggest health and safety breach fines of 2018.

A spokesman for the ONR had previously said: “An electrician suffered burns to his arms in the incident, which was a breach in conventional health and safety and did not involve any radiological risk factors.”

The AWE was convicted at Reading Magistrates’ Court of being an employer failing to discharge general health, safety and welfare duty to employee.