Sir Keir Starmer has praised Sadiq Khan’s commitment to clean air in London after last year urging the mayor to “reflect” on the expansion of the ultra-low emission zone (Ulez).

The Labour leader, who lives in north-west London, said he did not want his children to “breathe in dirty air” as he appeared alongside Mr Khan for the launch of the mayor’s re-election campaign.

The Ulez scheme was expanded last August to cover the entirety of Greater London, a controversial move overseen by Mr Khan.