Chown joined Sellafield as supply chain directors four years ago from Balfour, where he was procurement boss for the construction services business.

He said: “It’s an honour to become the chief executive of one of the most important companies in Britain.

“We’re responsible for some of the most significant and exciting environmental and engineering challenges anywhere in the world.

“I’m privileged to be able to lead a team of incredible professionals, supported by extremely capable supply chain partners at a critically important time in the evolution of the Sellafield site.”