What had been the Austin A135 Princess in 1952 became a Vanden Plas model in 1957, the prestigious badge being regarded as a way of making it seem even more upmarket. This cut-price Rolls-Royce had much to recommend it, becoming a particular favourite of mayors and successful businessman across Britain. Its 3993cc six-cylinder 122bhp engine made it a capable cruiser, and it could be had in three body styles; saloon, six-seater limousine or landaulette. An offshoot was the Princess IV of 1956, an expensive grand touring version intended to compete with Jaguar.
info from Octane