Transport for London told ITDP that they are at the early stages of studying the technical feasibility of the plan, as well as the extension of the current congestion pricing zone in central London.

A major consideration of the expansion, which would include most of the boroughs of Westminster, Kensington and Chelsea, is eliminating the 90% discount residents currently receive. It is likely that essentially exempting residents from the charge, particularly over a larger area, would drastically reduce the charge’s congestion mitigation effects.

Like with the congestion charge in central London, the revenue from Heathrow would be invested in public transportation for the corridor, which currently has very limited transit access. The Mayor said he planned to dedicate the funds to a railway line linking the airport to Central London via underground tunnels. The airport is 15 miles (24 km) west of central London.

A poll conducted during the second week of March by Market & Opinion Research International, the largest independently-owned market research company in Great Britain, found that the majority of Londoners support congestion charging in central London. Before the charge was implemented, polls showed an even split between those in favor of and opposed. Now, 50% said they backed the charge while 34% were against it.