The overall new car market plummeted by 20.5% in September, figures released by the Society of Motor Manufacturers and Traders show.

According to the SMMT, 338,834 cars were registered during the crucial plate-change month, 87,000 less than in September 2017 with the SMMT blaming the late introduction of the new WLTP testing regime.

The fleet sector was hardest hit, with fleet registrations dropping by 22.4% to 155,417 units – 45,000 less than 12 months ago.

Diesel car registrations continued to fall – by 42.5% compared with September 2017 – as did the number of petrol cars registered (down by 6.7%), however, the number of alternatively-fuelled vehicles registered during the month increased by 3.9% to 23,507 units.

New cars

Year-to-date performance is currently down by 7.5% compared with the first nine months of 2017, with the SMMT attributing this drop to weakening consumer confidence in the wake of the Brexit vote.

“With the industry given barely a year to reapprove the entire European model line-up, it’s no surprise that we’ve seen bottlenecks and a squeeze on supply. These are exceptional circumstances with similar declines seen in other major European markets. The good news is that, as backlogs ease, consumers and businesses can look forward to a raft of exciting high-tech cars and a market keen to recover lost momentum,” said Mike Hawes, SMMT chief executive.

Ashley Barnett, head of consultancy at Lex Autolease, added: “September’s decline is not unexpected, as new emissions testing has disrupted supply and uncertainty in the market is still affecting motorists’ ability to make confident purchasing decisions.  From a company car driver’s perspective, the lack of long-term clarity around tax means there’s no way of knowing a vehicle’s cost for the contract duration. Drivers of low-emission vehicles can be fairly confident that the government will favour them in its longer-term tax planning, but even they are keen for some assurance.