Boris Johnson ran for London's mayoral office partly on a platform of stanching the spread of his predecessor's rampant congestion charging. Now Johnson has said he'll 'brood' on the subject of ending the congestion charge altogether.

Earlier this year Johnson followed through on his campaign promise to stop the congestion charge expansion and rate hikes planned by former mayor Ken Livingstone. But Johnson is being cautious about scrapping the charge altogether, since congestion is a serious problem in the UK's capital city, and he'd like to avoid making the problem any worse, reports the UK's Environmental Transport Association (ETA).

The ETA thinks road-user charging, as it refers generically to the idea of requiring motorists to pay for their road use, is a necessary element to any successful congestion reduction scheme. “Evidence from around the world shows that it does not matter how many billions is invested in buses, trains or trams, as in Paris, Munich or Tokyo, without a road-user charge of some kind, the policy is doomed to failure,” said the ETA in a statement.

London's congestion charge has been famously contested by Porsche, declared both harmful to the environment and a failure at reducing congestion by Transport for London and generally reviled by anyone having to pay the hefty daily fees to access - or escape from - central London.