4-door 5-seater saloon.

Structure, suspensions and styling all as Mk III 1800, but fitted with new transverse (in-line) overhead-cam six-cylinder engine, coded E6, really one-and-a-half Maxi 1500 units; 110bhp gave 100mph top speed, still with Hydrolastic suspension. Extra price partly justified by new facia. As this was early seventies BL, naturally there were Austin and Wolseley, but no MG badge-engineered equivalents. Replaced by 18-22 variety after only three years.