Sinclair C5 Isetta, a 1960s Italian microcar. Sinclair built a full-scale mock-up of it; according to Wood Rogers, "it looked great. I specified open sides to keep the cost down and having no doors meant it escaped a lot of regulations too." The design is strikingly similar to the modern Renault Twizy electric vehicle; Wood Rogers comments that "you could put the C10 into production today and it would still look contemporary." At the time of the C5's launch, 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
Sinclair C5 until late 1979 that Sinclair returned to electric vehicle development. Around Christmas that year, he approached Tony Wood Rogers, an ex-Radionics employee, to carry out consultancy work on "a preliminary investigation into a personal electric vehicle". The brief was to assess the options for producing a one-person vehicle which would be a replacement for a moped and would have a maximum speed of . Although Wood Rogers was initially reluctant, he was intrigued by the idea of an electric vehicle and agreed to help Sinclair. The vehicle was dubbed the C1 (the C standing for Clive). He built a number