The Princess is a badge engineered variant of the Austin A99 Westminster, manufactured by BMC from 1959 to 1968 and marketed under the Vanden Plas marque.

The interior was lavish in typical Vanden Plas style, featuring burr walnut wood trim, leather seats and panels, and high-quality carpeting.

A Vanden Plas Princess 3-litre with automatic transmission was tested by the British magazine The Motor in 1961 and had a top speed of 99.3 mph (159.8 km/h).

Better brakes were fitted, and interior improvements included built-in drop-down "picnic tables" for the rear seat passengers.

[9] The engine resulted from more than two years technical collaboration between BMC and Rolls-Royce, and featured a cubic capacity of3.909 litres (239 cu in).

A new automatic transmission was provided, Borg-Warner model 8, its first use in a British car and Hydrosteer variable ratio power steering accompanied wider tyres.

However, its close appearance to its predecessor and its pricing (near to that of the Jaguar, which was bigger with a far more advanced chassis design and more prestigious, though itself without a useful market in the United States), resulted in slow sales.

[4] The late Queen Elizabeth ll owned an estate model of the Vanden Plas Princess, with an estimated production of 4-7.

Prototypes were made using the Austin-engineered central portion of the Vanden Plas, with restyled Rolls-Royce and Bentley panels front and rear.