Sinclair C5 | legacy
Sinclair envisaged producing follow-up vehicles such as the C10, a two-seater city car, and the C15, a four-seater capable of travelling at 80 miles per hour (130 km/h).
 As Wills put it at the launch event, "We're developing a family of traffic-compatible, quiet, economic and pollution-free vehicles for the end of the '80s." The C5 was described as "the baby of the family".
 The C10 was intended to be a city car, capable of carrying two passengers at up to 40 miles per hour (64 km/h) in a roofed but open-sided compartment with two wheels at the front and one at the back. Wood Rogers intended it to effectively be an updated version of the
Sinclair described the C15 as having "a futuristic design with an elongated 'tear-drop' shape, a lightweight body made of self-coloured polypropylene and a single, possibly 'roller' type rear wheel".
 It would have been launched at the 1988 International Motor Show in Birmingham following a development programme costed at £2 million. Unlike the relatively conventional technology used in the C5, Sinclair intended to use
Although Sinclair went on to produce more (but much smaller) electric vehicles, the C5 debacle did lasting damage to the reputation of subsequent EVs in the UK, which the media routinely compared to the C5. It was not until a highly regarded manufacturer,
Despite its lack of commercial success when it was first released, the C5 gained an unexpected degree of cult status in the later years.  Collectors began purchasing them as investment items,  reselling them for considerably more than their original retail price. One such investor, Adam Harper, bought 600 C5s from a film company as a speculative investment in 1987. He sold all but four within two years, selling them to customers who wanted a novel or more environmentally friendly form of transportation. He also found willing customers among drivers who had been banned from the road, as the C5 did not need a driving licence or vehicle tax.  According to Harper, C5s could be resold for as much as £2,500 – more than six times the original retail price.  By 1996, a Special Edition C5 in its original box was reported to be worth more than £5,000 to collectors. 
C5 owners began modifying their vehicles to achieve levels of performance far beyond anything envisaged by Sinclair. Adam Harper used one C5 as a stunt vehicle, driving it through a 70 ft (21 m) tunnel of fire,  and adapted another to run at 150 miles per hour (240 km/h), aiming to break a world land speed record for a three-wheeled electric vehicle and the British record for any type of electric vehicle.   He said later: "Up to 100 mph it's like you're running on rails, it's really stable. Then at about 110 to 120 mph it starts getting tricky. At that point if a tyre blew up or something happened you would be surely dead." 
As quoted in the 1987 Guinness Book of Records under battery powered vehicle; 'John W. Owen and Roy Harvey travelled 919 miles 1479 km from John O'Groats to Land's End in a Sinclair C5 in 103 hr 15 min on 30 Apr-4 May 1985.'(8.9 mph avg.)
Chris Crosskey, an engineer from