The SD1, launched in 1976, was intended to replace Triumph's 2000/2500 range as well as the previous Rover models. The SD1 was face-lifted in 1981 and total production reached around 300,000.

An estate version was intended to compete against rivals from Volvo and Ford and Carbodies was commissioned to provide a full styling model but the two running prototypes were produced in-house at Solihull. The two estates were converted from saloons. The cars differed slightly in rear end design – this one with a recessed tailgate and the other with a clamshell type, as modelled by Carbodies.

During the late 1970s, an SD1 estate was used by Sir Michael Edwardes for commuting around London. Both prototypes still survive.