This distinctive-looking five-door family saloon is the only surviving prototype of the SD2, a design scheduled to replace Dolomite. Proposed engines were the Triumph 1500cc, the O-series and a fuel-injected Dolomite Sprint 16-valve two‐litre. This SD2 prototype carries the Sprint unit.

British Leyland's financial state in the late 1970s was poor and it faced drastic rationalisation. It became evident that considerable investment would have been necessary to put SD2 into production. There was also debate within BL whether a rear-wheel-drive car was the best technical format for the medium-sized car market

Instead Triumph's history took a different turn and the Dolomite was replaced by a BL-Honda collaboration which emerged in 1981 as the Triumph Acclaim.