Competition model developed from the 'M'-type. 746-cc, 4-cylinder, ohc engine. Single SU carburetor (44 bhp at 6400 rpm) or supercharged (52.4 bhp at 6500 rpm). Four-speed gearbox. Half-eliptic springs. Centre-lock wire wheels. Two-seater racing body with cowled radiator. 44 built.

See magazine article:
Road Test Montlhery M.G.Midget - Autocar November 20, 1931 (0.4-MB pdf)

EX121 leads to the "Montlhery Midget" above,
and to EX 127, the "Magic Midget" record setting car below.