British Leyland was a vehicle manufacturing company formed in the United Kingdom in 1968 as British Leyland Motor Corporation Ltd (BLMC). It was partlynationalised in 1975 with the government creating a new holding company called British Leyland Ltd which became BL Ltd (later BL plc) in 1978. It incorporated much of the British owned motor vehicle industry, and held 40% of the UK car market, with roots going back to 1895.
Despite containing profitable marques such as Jaguar, Rover and Land Rover, as well as the best-selling Mini, British Leyland had a troubled history. In 1986 it was renamed as the Rover Group, later to become MG Rover Group, which went into administration in 2005, bringing an end to mass car production by British owned manufacturers—with MG and the Austin, Morris and Wolseley marques becoming part of China’s SAIC, with whom MG Rover attempted to merge prior to administration.
Info gleaned from Wikipedia