Sadiq Khan
The Labour leader is facing a growing backlash over his response to the war.
The Tories claim the scheme is part of Labour's "war on motorists".
Susan Hall has earlier been defended by home secretary Suella Braverman.
Susan Hall was accused of "dog whistle politics" over her comments at the Conservative conference.
London's mayor has announced a new scheme following the fallout from the Uxbridge by-election.
Sadiq Khan's clean air scheme has caused a rift with Keir Starmer after it was blamed for Labour's by-election loss in Uxbridge.
“British journalism has lost a talent,” Labour leader Keir Starmer tweeted.
Sources close to the London mayor now say he is "listening" in the wake of Labour's defeat in Uxbridge.
Danny Beales said it had "cut us off at the knees" as the Tories clung on by just 495 votes.
The results in Selby and Uxbridge threw up as many questions as answers for Labour.