The “most important Aston Martin ever produced” became the most valuable British-made car ever when it sold for £17.5 million ($22.5 million) at the recent Monterey Car Week in California.

The 1956 Aston Martin DBR1 — the firm’s equivalent of the Ferrari 250 GTO and the Mercedes-Benz 300 SLR — was one of just five built between 1956 and 1958.

This one is chassis number one — a purpose-built model developed by racing design chief Ted Cutting. This particular car won the Nurburgring 1,000km race that same year.

It was subsequently sold, converted and made legal for street use in 1962. One of the other five won the 1959 24 Hours of Le Mans sports-car race.

The DBR1’s in-line six-cylinder engine evolved from its debut in 1956 though to its last race in 1959, ending up at 2,992cc and 268hp.

The original engine was included in the price of the car, which currently has a modern engine with no historical value. This new engine raised the car’s output to 301hp.

On the same day, rival auction house Bonham’s sold a 1995 McLaren F1 — the first of its model to sell in the USA — for £12.2 million ($15.62 million). The F1 was the most advanced car the world had ever seen, when it was launched in the early 1990s.

It was also the fastest, being capable of accelerating from 0 to 62mph in 3.2sec and hitting a top speed of 243mph.

Just 65 road cars were built, and this model, known as chassis 044, remains as it left the Woking factory in 1995.