In a letter to London’s transport commissioner Andy Lord, Sadiq Khan has pledged not to expand London’s ULEZ scheme if he if he is re-elected as Mayor in May. and he also “categorically” ruled out the introduction of a pay-per-mile scheme as well as any additional emissions measures, reports the London Evening Standard.

“There is clearly still more to do to tackle air pollution, and I’m determined to continue leading from the front in London,” wrote Mayor Khan. But my commitment to Londoners is this will not include a new pay-per-mile road user charging scheme or amending the standards for the Ulez scheme.

“The introduction and expansion of the Ulez has been necessary and effective. But now it’s in place and working, I will ensure the goalposts are not moved for drivers.”

Khan also wrote that other measures to tackle air pollution, including improving walking and cycling routes, making buildings more energy efficient and expanding the network of electric vehicle charging stations will be his focus should be win a third term.

A spokesman for the mayor said: “Sadiq has been clear that he has ruled out the introduction of a pay-per-mile road user charging scheme but the Tories are clearly trying to mislead Londoners by repeatedly saying this is not the case. “The mayor has now put in writing to the TfL commissioner his clear pledge to London: no pay-per-mile scheme will be introduced while he is mayor.”