Sadiq Khan’s controversial Ulez scheme has been described as the deciding factor in the Conservatives holding onto Boris Johnson’s old seat of Uxbridge and South Ruislip.

The cleaner-air levy has faced opposition since it was introduced 2019, with the intention of purifying London’s air. Drivers of more-polluting vehicles are subject to a £12.50 tax in the ultra low emission zone, in a move similar to the congestion charge.