Mayors of Oslo, Montreal and Milan back Sadiq Khan on London Ulez plan

City leaders say UK capital's scheme to improve air quality is inspiring and explain their own measures

Mayors from cities around the globe have urged Sadiq Khan to stay strong in the face of harsh criticism of his clean air policies.

The Conservative party narrowly held the constituency of Uxbridge in a recent byelection, with its victory attributed partly to opposition to the London mayor's upcoming extension of the capital's ultra-low emissions zone (Ulez). A culture war over the role of cars in cities has erupted which has included arch comments from Keir Starmer, the Labour leader, who suggested his party was doing something very wrong".