Announced in August 1964, the Princess 4-Litre R featured a Rolls-Royce, all-aluminium, 175bhp engine enabling an unusually high power-to-weight ratio enabling cruising at 90mph and a top speed in period of 112mph.

The engine was the product of over two years of technical collaboration between BMC and Rolls-Royce.

Twin SU carburettors were fitted, both the cylinder block and head were aluminium, tappets were hydraulic self-adjusting operating on overhead valves configuration and the counter-balanced crankshaft ran in seven main bearings, reducing vibration.

Pricing aimed at challenging the MkX Jaguar was a major change of market positioning, aiming at growth in the prestige and executive market segments of Europe and the United States.

The 4.0 R was luxurious with polished walnut fascia, padded top and bottom, fully reclinable leather seats and polished picnic tables for the rear passengers.

A new automatic transmission was provided by Borg-Warner; its first use in a British car, ...