The basic concept for the minicar was derived from a prototype built by Lawrence "Lawrie" Bond, an engineer from Preston. During the war, Bond had worked as an aeronautical designer for the Blackburn Aircraft Companybefore setting up a small engineering business in Blackpool, manufacturing aircraft and vehicle components for the government. After the war he moved his company to Longridge where he built a series of small, innovative racing cars, which raced with a modest amount of success. In the early part of 1948, he revealed the prototype of what was described as a new minicar to the press.
Described as a "short radius runabout, for the purpose of shopping and calls within a 20-30-mile radius", the prototype was demonstrated climbing a 25 per cent gradient with driver and passenger on board. It was reported to have a 125 cc (8 cu in) Villiers two-stroke engine with a three-speed gearbox, a dry weight of 195 pounds (88 kg) and a cruising speed of around 30 mph (48 km/h). At the time of the report (May 1948), it was stated that production was "expected to start in three months' time". The prototype was built at Bond's premises in Berry Lane, Longridge where it is now commemorated with a blue plaque.
Sharp's Commercials was a company contracted by the Ministry of Supply to rebuild military vehicles. Knowing that the Ministry were ending their contract in 1948, and recognising the limitations of his existing works as a base for mass production, Bond approached the Managing Director of Sharp's, Lt. Col. Charles Reginald 'Reg' Gray, to ask if he could rent the factory to build his car. Gray refused, but said that instead, Sharp's could manufacture the car for Bond and the two entered into an agreement on this basis. Bond carried out some further development work on the Minicar, but once mass production was underway, left the project and sold the design and manufacturing rights to Sharp's.
The prototype and early cars utilised stressed skin aluminium bodywork, though later models incorporated chassis members of steel. The Minicar was amongst the first British cars to use fibreglassbody panels.
Though retaining much of Lawrie Bond's original concept of a simple, lightweight, economical vehicle, the Minicar was gradually developed by Sharp's through several different incarnations. The majority of cars were convertibles, though later, hardtop models were offered, along with van and estate versions. Minicars were generally available either in standard or deluxe form, though the distinction between the two was largely one of mechanical detail rather than luxury. The cars were powered initially by a single-cylinder two-stroke Villiers engine of 122 cc (7 cu in). In December 1949 this was upgraded to a 197 cc (12 cu in) unit. The engine was further upgraded in 1958, first to a single-cylinder 247 cc (15 cu in) and then to a 247 cc (15 cu in) twin-cylinder Villiers 4T. These air-cooled engines were developed principally as motorcycle units and therefore had no reverse gear. However, this was a minimal inconvenience, because the engine, gearbox and front wheel were mounted as a single unit and could be turned by the steering wheel up to 90 degrees either side of the straight-ahead position, enabling the car to turn within its own length.
A method of reversing the car was offered on later models via a reversible Dynastart unit. The Dynastart unit, which doubled as both starter motor and dynamo on these models incorporated a built-in reversing solenoid switch. After stopping the engine and operating this switch the Dynastart, and consequently the engine, would rotate in the opposite direction.