The Rootes group (Triumph-Rover-MG-Austin Healy and maybe a few others) is no more.

Arrgh! Sacriledge! String the colonist up! Blasphemy!
The Rootes group was Hillman, Hunter (and before you start making comments, Hunter was a separate company before the Hilman Hunter was produced), Talbot and a few others that were bought up by Chrysler in the late 60's. The group collapsed when Chrysler pulled out of Europe, and the remains were bought up by Citroen/Peugeot Combine PSA.
The BMC, then British Leyland, then BL, then BL Cars, combine eventually split into Austin-Rover and Jaguar-Triumph. When Jaguar went private, the A-R group bought up the Triumph name and collapsed the product range to remove competiton from the superior Triumph saloons. Jag nearly folded again and were bought out by Ford. Austin disappeared as a brand as Honda came more onto the scene. When Rover were bought by BMW, and then split, they took the Mini as a separate brand, also taking Riley, Elf and Triumph with them (there is talk that BMW wants to resurrect the Triumph TR).
Like Cooper, Austin-Healey was a deal between a specialist and a major manufacturer to improve marque visibility; Healey dropped his arrangement with BL's arrival and went into partnership with Jensen to produce the truly awful Lotus engined Jensen Healey. This died a death and Healey's son now builds new Healey 1000's and 3000's to order based on modern mechanicals in the Isle of Wight.
Jag are in mass production, along with Rover, and Peugeot. Land Rover is now owned by Ford as well as A-M. The odd thing is, Jag and A-M have vastly improved under Ford, so I am pleased that they have bought L-R, as it means new models and improved reliability (at last).
Help enough?

One of the few remaining Mk1 owners...
#00015