In 1921 Frenchman Bertrand Montet founded the firm Derby at a time when cycle cars were riding a wave of popularity.  The first Derby was  fitted with a motorcycle V- twin imported from America.  This was soon replaced by a Chapuis-Dornier 4 cylinder 900 cc, water cooled engine  Both these models had three speeds.  The radiator of the Chapuis-Dornier Motor looked a bit like the then popular 5 CV Citroen.  
In the following year different kinds of motors were used including Ruby and SCAP.  The Derby was made in several sport versions the most powerful being the Special, with a SCAP 1100 cc engine with three valves for cylinder and, as an option, a Cozette supercharger.  Although in 1928 two 6 cylinder touring cars with lateral valves were produced, the marque was particularly known for its sports cars.  
The Derby was sold in England in the 1920s under the name of Vernon-Derby for Vernon Balls. (See picture of blue car below)  
When Bertrand Montet died in 1928, the firm was taken over by the Englishman W. D. Hawkes who produced a front wheel drive car inspired by the revolutionary American Miller.  Its reputation was enhanced in 1930 when Miss Gwenda Stewart established several records at Montlhery driving a Derby with a Miller racing engine  
This new sporty model was presented to the public in 1931, three years ahead of the ‘traction avant’ Citroen. The new Derby had the reputation of exceptional road handling.  The marque was deluged with orders, but it could only produce 200 models a year.   
Although the firm shifted to bigger premises in 1932 financial difficulties had begun to appear.  
The last Derby cars were the most interesting.  The L2 of 1931 was a four cylinder, 6 CV (horsepower) front wheel drive, and the L.8 of 1933 was an 11 CV front wheel drive, with a 2 litre V8 motor.  Also at that time there was another model fitted with a Meadows  ED 1.5 litre engine.  
In 1933, the market seemed doomed, but in one last effort, W. D. Hawkes launched a luxury front wheel drive V8, at a time when this kind of car was not popular. However, it stunned the opposition and stung Citroen into presenting its own V8 (a front wheel drive 22 horsepower car) a year later (but this car was not produced in any number).   The firm decided to stop making cars in 1936, probably because they were overly crafted compared to big volume production cars.  
 Picture kindly made available from http://www.velocityjournal.com