This vehicle remained significant in the classic car industry and represented luxury during the 1950s and 1960s.

Armstrong Siddeley Sapphire or “Royal Car” is a vehicle which was designed and manufactured by Armstrong Siddeley Motors Limited from 1952 to 1960. The Royal Car symbolized luxury and power during the mid-20th century in the post-World War II era. It was utilized for ceremonial purposes by the royal palace.

The Armstrong Siddeley Sapphire R.R.L 21 is a special model produced for use by the Thai royal family. It features a longer chassis design than standard models and particularly luxurious interior decorations. The number of productions was limited. It was equipped with 6-cylinder 3,435 CC Radial engine, capable of producing up to 150 horsepower. This car was elegantly designed and suited for those seeking high-end vehicles of that era. Additionally, the new model — the Sapphire 346, was developed in 1956 with a larger 3,995 CC engine and a maximum power of 155 horsepower. This vehicle remained significant in the classic car industry and represented luxury during the 1950s and 1960s. It was renowned for its luxurious design and the highest quality production of its time.