August was the 18th month of consecutive rises in the UK's new car market as registrations ended 10.9% ahead year-on-year.
The 65,937 cars registered in the final month of the 13-plate has driven up the year-to-date total to 1,391,788 units.
Private registrations saw the biggest gain, up 14.7% to 31,608 cars, but the fleet and business sectors also experienced improvement, up 7.4% to 32,386 units and 13.4% to 1,943 units respectively.
"UK new car registrations have now risen consecutively for a year and a half. Private and fleet buyers are clearly capitalising on attractive deals and new technologies against a backdrop of increasing economic confidence," said Mike Hawes, the SMMT's new chief executive.
"Ahead of the September plate-change, August always has far fewer registrations, but the 10.9% rise this month bodes well for the new 63-plate."
The Ford Fiesta was remained the monthly best-seller, followed by the Vauxhall Astra in 2nd place, the Volkswagen Golf in 3rd spot and the Ford Focus in 4th.