He was trapped against a metal handrail in the receipt and storage facility, which houses fuel transport flasks prior to reprocessing.

Sellafield said: “An investigation is being carried out into how an employee was injured whilst working in the Thorp receipt and storage facility. It appears that the worker became trapped between a fuel transport flask and a handrail.”

It continued: “Sellafield emergency services were immediately called; initially the individual was taken to the site surgery and then transferred to the West Cumberland Hospital. At this stage we have no further details on the health of the employee. One of our site doctors is keeping in touch with the hospital and the family. We can confirm that there have been no nuclear safety consequences.”

And added: “It is not acceptable that any of our workforce get injured whilst at their place of work. We will thoroughly investigate the root cause of this accident to ensure that lessons are learned and shared throughout the business.”

The UK’s Health & Safety Executive (HSE) has been notified.