The Volvo P1800 is one, and two-passenger, front engine, rear-wheel drive two-door touring car (instead of a real sports car) manufactured and marketed by Volvo Cars as a coupe (1961-1973) and brake-shot (1972- 1973).

Widely known as the car driven by Roger Moore on the television series The Saint (1962-1969), the P1800 featured styling by Pietro Frua and mechanicals derived from the Amazon / 122 Volvo series.

In 1998, a P1800 was certified as the largest private mileage vehicle driven by the original owner in non-commercial service - having exceeded three million miles as of 2013.

The project was originally started in 1957 because Volvo wanted a sports car to compete in the North American and European markets, despite the fact that its previous attempt, the P1900, failed to take off with only 68 cars sold. The man behind the project was an engineering consultant for Volvo, Helmer Petterson, who in 1940 was responsible for the Volvo PV444. The design work was done by the son of Pelle Petterson Helmer, who worked at Pietro Frua at that time. Volvo insisted that it was an Italian design by Frua and only officially recognized that Pelle Petterson designed it in 2009. The Italian company Carrozzeria Pietro Frua project (then a newly acquired subsidiary of Ghia) built the first three prototypes between September 1957 and early 1958 , later designated by Volvo in September 1958: P958-X1, X2 and P958-P958-X3 (P: Project, 9: September, 58: Year 1958 = P958, X: experimental.).

In December 1957 Helmer Petterson drove X1, (the first hand-built P1800 prototype) to Osnabrück, West Germany, Karmann's headquarters. Petterson hoped that Karmann would be able to take over the tooling and construction of the P1800. Karmann engineers had previously been preparing work drawings of the wooden styling buck at Frua. Petterson and Volvo chief engineer Thor Berthelius met there, tested the car and discussed the construction with Karmann. They were ready to build it and that meant that the first cars could hit the market as early as December 1958. But in February, Karmann's most important customer, Volkswagen VAG, forbade Karmann to take on the task.

They feared that the P1800 would compete with sales of their own cars, and threatened to cancel all of their contracts with Karmann if they took over this car. This setback almost caused the project to be abandoned.
Other German companies, NSU, Drautz and Hanomag, were contacted, but none were chosen because Volvo does not believe that they met Volvo's quality control manufacturing standards.

It started to look like Volvo might never produce the P1800. This motivated Helmer Petterson to obtain financial support from two financial companies with the intention of buying the components directly from Volvo and marketing the car itself. At this point Volvo had made no mention of the P1800 and the factory declined to comment. Then, a press release surfaced with a photo of the car, putting Volvo in a position where they had to acknowledge its existence. These events influenced the company to renew its efforts: the car was first presented to the public at the Brussels Motor Show in January 1960 and Volvo turned to Jensen Motors, whose production lines were underutilized, and they agreed to a contract for 10,000 cars.

The Linwood, Scotland, vegetable manufacturer's pressed steel body was in turn subcontracted by Jensen to create the unibody shells, which were then taken by rail to be assembled at Jensen in West Bromwich, England. In September 1960, the first production P1800 (for the 1961 model year) left Jensen for an anxious audience.
P1800

The engine was the B18 (B for the Swedish word for gasoline: Bensin; 18 for 1,800 cc displacement) with double SU carburetors, producing 100 hp (75 kW). This variant (named B18B) had a higher compression ratio than the slightly less powerful twin-carb B18D used in the contemporary Amazon 122S, as well as a different camshaft. The 'new' B18 was actually developed from the existing B36 V8 engine used on Volvo trucks at the time.

This reduced production costs, as well as providing the P1800 with a strong engine boasting five main crankshaft bearings.

The B18 was combined with the new and more robust M40 manual gearbox through 1963. From 1963-1972 the electrically driven M41 overdrive gearbox was a popular option.

Two types of overtaking were used, the D-Type until 1969, and the J type to 1973. The J type had a slightly shorter ratio of 0.777: 1, as opposed to 0.756: 1 for the D type.

Overtaking effectively gave the 1800 series a fifth gear, to improve fuel efficiency and less drivetrain wear.

Cars without overdrive had a numerically lower differential ratio, which had the interesting effect of giving them a slightly higher maximum speed (just under 120 mph (193 km / h)) than the most popular overdrive models.

This was because non-overtaking cars could reach the engine's redline at the highest gear, while overtaking-equipped cars could not, giving them a top speed of around 110 mph (177 km / h).