Fleets were urged to back European Car Free Day - In Town Without My Car - which aims to show town residents the benefits available from traffic reduction and encourage them to use alternative transport in future.
But Richard Evans, organiser of the event on behalf of the green motorists' group, the Environmental Transport Association, said: 'We have 10 local authorities taking part, despite the fact that there is no national support. The Government is now the only one in Europe not to have signed up to support the day.'
Last year 66 French cities and 92 Italian cities took part and car-free areas were established in large parts of city centres during the day, in which 22 million people took part and 85% said they wanted it to be regularly repeated.
Speaking at the launch event, Ken Livingstone, mayor of London, gave his backing to the event and promised that next year, he would consider closing some of the road's under his direct control as part of the day, which is held on September 22 every year.
- Details on the Car Free Day are available on the Environmental Transport Association website on the FNN Buyers guide in the Associations and official bodies section.