New car registrations fell to their lowest level in nearly three decades last year, according to preliminary figures from the industry's trade body.
It was also the biggest one-year fall since World War Two, when factories were being turned over to military production, the Society for Motor Manufacturers and Traders said.
About 1.63 million new cars were registered in 2020, compared with 2.3 million in 2019 - a decline of 29%.
It was the lowest total since 1992.
The bulk of the lost sales occurred during the first lockdown in the Spring, when showrooms were forced to close, and factories shut down.
"We lost half a million units from March, April, May - and we never recovered them," said the SMMT's chief executive, Mike Hawes.
The restrictions introduced later in the year were less damaging, largely because dealers were able to sell cars remotely, using 'click and collect' services.
That remains the case during the new lockdown, announced on Monday.
"We can still do click and collect, which is important, because that's the very minimum we need," said Mr Hawes. "Not just to keep retail going, but also to keep manufacturing going."
Overall, the SMMT said the Covid crisis has cost the car industry some £20bn - and cost the exchequer nearly £2bn in lost VAT.
Source: BBC