The Quantum Mark 1 was manufactured by Quantum Sports Cars in the 1980s. It was based on the Mark 1 Ford Fiesta. The car reused all of the donor's mechanical and trim components in an elongated, more rounded shape. Due to its reduced weight over the donor vehicle, performance was significantly improved. The Coupé is unusual for low-volume car manufacture in that it has a glass-reinforced plastic (grp) monocoque rather than a separate metal chassis. This approach relied upon the use of computer analysis to ensure that structural rigidity would not be compromised, offering the strength of a steel chassis but without the weight penalty.

The first Mark 1 Quantum, bearing chassis number 001, was a development mule and was subject to so much adjustment that the Wooldridge brothers eventually decided the car would be too dangerous to keep on the road. This car was therefore disposed of in landfill. Chassis 002 was later damaged beyond repair in a head-on collision, so chassis 003 is now the oldest surviving example of a Quantum model and the first to be sold, after a short period being used for magazine tests and promotional materials. To ensure this historic car survives, the Quantum Owners Club has acquired this car and are in the process of restoring it. The last Mark 1 Coupé produced, chassis number 017, is also now owned by the club.

In 1991, a restyled version was introduced, now based on the Mark2 Ford Fiesta with the rear-end shape changed from a hatchback to a saloon. This and other styling revisions led to far greater sales success: a total of 215 saloon models were produced before that model also ceased production.