Car Clubs

Carplus – UK's non-profit network for car clubs
Smart Moves – largest car club operator in the UK
WhizzGo – book a car nearby instantly by phone or online

Cities

London 21 Sustainability Network – aims to promote, support and network community-based action for sustainability in London

Transport

Critical Mass – bicycle movement
Cycle Campaign Network – UK federation of cycle campaign groups
Cycling Touring Club – offers a comprehensive and specialised service for the leisure and commuting cyclist
Environmental Transport Association – aims to raise awareness of the impact of excessive car use and help individuals and organisations to make positive changes
International Forum for Rural Transport and Development (IFRTD) – global network of individuals and organisations interested in rural transport issues in developing countries
Sustrans – sustainable transport charity works on practical projects to encourage people to walk, cycle and use public transport
Transport 2000 – national environmental transport body