Sinclair C5 major consumer organisations published sceptical evaluations. The Automobile Association questioned many of Sinclair's claims in a report published at the start of May. It found that the range of the vehicle was typically only about 10 miles (16 km) rather than the promised by Sinclair, and reported that the C5's battery ran flat after only on a cold day. The C5's running speed was more usually around than the claimed , while its running costs compared unfavourably to that of a petrol-driven Honda PX50 moped. The stability, general roadworthiness, and especially the safety of the C5 were questioned, and the
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