In the year to date, car sales were down 7.5 percent compared with the first nine months of 2017, the Society of Motor Manufacturers and Traders (SMMT) said.

On Sept. 1, the Worldwide Harmonised Light Vehicle Test Procedure came into force in the European Union, which led some brands to incentivise sales in August, pulling forward demand.

"These are exceptional circumstances with similar declines seen in other major European markets," SMMT chief executive Mike Hawes said.

(Reporting by Andy Bruce; Editing by William Schomberg)