Surging demand for diesels has doubled waiting lists for some popular models, according to dealers, leading to accusations that carmakers failed to recognise the expected boom. The average lead time for delivery has risen to 16 weeks.

Fleets have stimulated much of the demand, raising concerns about future residual values. HSBC Vehicle Finance said diesels accounted for 40% of vehicles ordered in April, as demand rose 43%.

The UK is playing catch-up with continental markets: diesels account for more than 30% of the market in Germany and almost 50% in France.