It was Sadiq Khan’s extension of the Ultra Low Emission Zone (Ulez) to outer London that won it for the Tories. This diabolical scheme to penalise drivers of older cars and van-owning tradesmen in the outer suburbs has aroused a level of rage which must now be a lesson to all serious contenders in the general election. The ramifications go far beyond this single, apparently anomalous, success for the Conservatives.