[2] Codenamed ADO61, the car was intended to be BMC's offering in the 3-litre executive class and was originally designed in the early 1960s,[3] before the British Leyland era.

Unlike the visually similar (but smaller) front-wheel drive Morris 1800 range, the 125 bhp 3-litre engine (a 7-bearing modification of the BMC C-Series with twin SU carburettors) drove the rear wheels through a conventional 4-speed gearbox.

[7] In the early days of British Leyland, proposals for a Rover-branded version were considered to replace the Rover P5 3-Litre but these did not progress beyond the drawing board.

Cars such as the Rover P6 and the Triumph 2000 had set new standards for handling in the class and had smaller but more efficient engines as well as more fashionable and modern styling.

The 3-Litre was very much in the spirit of its Austin Westminster predecessor – a large car with an understressed large-capacity engine that put an emphasis on luxury and ride comfort over handling and economy, although both these last two factors were becoming more important in the sector.