The Ultra Low Emission Zone could be expanded across all London boroughs by 2023 under plans announced over the weekend.

Mayor of London, Sadiq Khan, has asked TfL to consult on expanding the Ultra Low Emission Zone London-wide, warning the greatest number of deaths attributable to air pollution are in London’s outer boroughs.

He is also asking TfL to draw up plans for introducing a Greater London Boundary Charge for vehicles driving into London and implementing a low-level daily Clean Air Charge for all but the cleanest vehicles as alternative options.

He said that while smart road user charging would be the fairest solution in the future - which would enable existing road user charges to be scrapped - TfL is still many years away from being able to implement such a scheme.

Mayor Sadiq Khan, said: 'In weighing up the different options, the rising cost of living was a key consideration for me. Because at a time when people’s budgets are under pressure, I’m not willing to ask people to pay more unless I’m absolutely convinced it’s justified to save lives and protect the health of Londoners.

'I believe the proposal to extend the ULEZ London-wide will have the biggest effect on emissions and congestion relative to the potential financial impact on Londoners as a whole. We are also proposing to introduce the biggest scrappage scheme feasible to help Londoners on low incomes, disabled Londoners and businesses.'

The mayor has now ruled out both the Clean Air Charge and the Greater London Boundary Charge as options going forward.