RAC roads policy spokesman Nick Lyes said: "We welcome the introduction of the T-charge as nobody denies that action is needed to clean up London's air pollution and it quite rightly tackles the most polluting vehicles first.
“We are, however, concerned that it coming into force in October doesn't give owners of vehicles affected by the charge much time to acquire newer ones. What’s more, owners of these older vehicles are also those that are likely to be less well-off and therefore may struggle to purchase a cleaner vehicle in such a short period of time. It could also disproportionately impact on struggling smaller businesses.
“Given the short amount of time before the charge is brought in there really ought to be incentives to help owners trade in their older diesel vehicles.
“We also need to see a renewed push by City Hall to replace some of the dirtiest buses on London's roads and a renewed effort to get congested roads moving.
“Motorists need to be very careful in checking whether their vehicle is affected or not. The best advice is to visit the TfL website.”