Mayor of London Ken Livingstone wants to broaden his congestion charging scheme and make drivers pay the £5 charge to drive to the airport. Money raised would be used to lower the cost of travelling to Heathrow on public transport.
Staff working at Heathrow and all firms supplying the airport would be exempt.
Meanwhile, Livingstone has given the clearest signal yet he will introduce congestion charging. He said the public consultation on the road charging scheme had produced 'no new arguments or any striking presentation of the arguments that leads me to think we should drop the proposals.'
Transport for London has already committed millions of pounds in development costs to the scheme, and has pledged to spend up to £20 million in development costs as part of its five-year £230 million contract with management firm Capita to run the scheme. Protesters say the contract commits the capital to congestion charging.
However, TfL says the money will be used to set up a congestion monitoring system.
Meanwhile, new research calls for company car drivers to be taxed according to how much they jam UK roads.
In a report due for publication next month, the Commission for Integrated Transport will argue a system of direct charging will encourage drivers to travel during off-peak hours.