The TMC Costin was a lightweight sports car built from 1983 to 1987 at the Thompson Motor Company in Wexford, Ireland.

It was designed by the aerodynamicist and Marcos founder Frank Costin and was intended to be an Irish-made rival to Lotus Seven-inspired cars as manufactured by companies such as Caterham and Westfield. Costin had previous associations with Lotus and Maserati for race-car chassis designs.

The cars were very successful in racing, but just 39 cars were built before TMC went bankrupt in 1987. The chassis rights were sold to the American Daniel Panoz, founder of Panoz Auto Development, which still builds the Panoz Roadster which is based on the Costin.

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