The LDS Mk III (also referred to as the Mk 3 or Mk 3B) represents the pinnacle of South African Formula One construction. Built by racing driver and engineer Doug Serrurier, it was the tenth and ultimate LDS chassis ever constructed.

Unlike the earlier LDS Mk 1 and Mk 2 models which were inspired by Cooper chassis, the Mk III was built with assistance from Jack Brabham's team. It was an authorized, faithful copy of the Brabham BT11 spaceframe design. The car was specially commissioned by local racing driver Sam Tingle and debuted at the tail end of 1965.

The car was specially commissioned by local racing driver Sam Tingle and debuted at the tail end of 1965.

 

It originally competed utilizing a 2.5-liter or 2.7-liter Coventry-Climax FPF four-cylinder engine, outputting roughly 180 horsepower. For the 1968 season, it was upgraded to a 3.0-liter Repco 620 V8 engine to comply with newer F1 engine regulations.

The Mk III found immense success in the South African Formula One Championship. Driven primarily by Sam Tingle, it secured 2 victories, 10 second-place finishes, and 7 third-places across 30 domestic and international races. Tingle finished runner-up in the overall SA F1 Championship in both 1966 and 1967.

The LDS Mk III holds a unique place in global motorsport history. For the 1968 South African Grand Prix, it was entered by Team Gunston. Painted in the brown, orange, and gold colors of the Gunston cigarette brand, it became part of the very first Formula 1 team in the world to feature full commercial tobacco sponsorship, predating Lotus's famous Imperial Tobacco sponsorship by a few months.