This 406 is a unique Bristol in that it’s fitted with the Armstrong Siddeley Star Sapphire engine.

In the late 1950s The Bristol Aeroplane Company and the Hawker Siddeley Group had agreed to co-ordinate their activities in order to win a contract from the government to build the Olympus aero engine.

The combination of their engine divisions, Bristol Aero Engines and Armstrong Siddeley Motors, resulted in Bristol Siddeley Engines Ltd.

This company, and later on Rolls-Royce Aero Engines eventually developed the Pegasus engine which was seen some twenty years later in the Harrier ‘jump jet’.

Bristol Cars Ltd became a subsidiary of Bristol Siddeley.

The new board expressed interest in increasing the number of Bristol cars produced, and the Siddeley engines could have proved useful to reach their targets.

With Siddeley three and four litre V8 engines in the pipeline they decided that the natural starting point was the three litre straight six: the Star Sapphire.

It was a large engine...