[3] British Nuclear Fuels Limited (BNFL) was set up in February 1971 from the demerger of the production division of the UK Atomic Energy Authority (UKAEA).

In 1984, BNFL became a public limited company as British Nuclear Fuels plc, wholly owned by the UK government.

[7] A Nuclear Installations Inspectorate (NII) investigation concluded that "the level of control and supervision ... had been virtually non-existent.

"[8] BNFL had to pay compensation to the Japanese customer, Kansai Electric, and take back a flawed shipment of MOX fuel from Japan.

Westinghouse's businesses are fuel manufacture, decommissioning of nuclear sites and reactor design, construction and servicing.

[19] In January 2003, the research and development arm of BNFL was relaunched as Nuclear Sciences and Technology Services (NSTS).

[22] This new BNFL operated largely through its major subsidiaries of Westinghouse and BNG as well as Nexia Solutions, its commercial nuclear technology business formed out of NSTS.

[26] On 6 February 2006, Toshiba confirmed it was buying Westinghouse Electric Company for $5.4bn and announced it would sell a minority stake to investors.

[30] In January 2007, BNFL announced that it would sell BNG's Magnox reactor sites operating business, Reactor Sites Management Company Ltd.[31] It was later sold in June 2007, along with its subsidiary that held the operating contracts with the NDA, Magnox Electric, to EnergySolutions.

In October 2006, Secretary of State for Trade and Industry, Alistair Darling confirmed the NNL would be formed out of Nexia Solutions and the British Technology Centre at Sellafield.

In March 2024, Great British Nuclear bought the Oldbury and Wylfa sites from Horizon in a deal worth £160m.

[43][44] GBN is led by Gwen Parry-Jones as interim chief executive officer, who was formerly the CEO of Magnox Ltd.[45] Its chair is Simon Bowen.