New car sales fell for the first time in six years last year with demand for diesel cars plunging by almost a fifth.
In total, there were around 2.5 million cars registered, according to industry body the Society of Motor Manufacturers and Traders (SMMT).
The figure was down 5.6% from 2016, while diesel sales fell 17% as higher taxes and pollution fears hit demand.
SMMT chief executive Mike Hawes said he expected car sales to continue to drop this year, predicting a 5 to 7% fall.
The figures are preliminary, with final numbers for the year due to be published later.
Mr Hawes blamed the sales fall on declining business and consumer confidence, but pointed out last year’s performance followed two years of record sales.
“We need to put it into context. This was still the third best year in a decade and the sixth best ever,” he added.
Mr Hawes said that confusion about the future of diesel had fuelled a backlash against diesel cars.
Diesel vehicles produce the overwhelming majority of nitrogen oxide gases coming from roadside sources.