October car registrations were up by a third compared to the same month last year.
Last month, 186,942 cars were registered, a 31.6% increase.
Year-to-date registrations are down 12.3%.
New car registrations were up 31.6% in October to 168,942 units.
It is the fourth month of growth sustained by the scrappage scheme.
Private demand is up 86% this month, further demonstrating the impact of scrappage.
Paul Everitt, SMMT chief executive, said: “October has seen this year’s biggest monthly increase in registrations with the successful scrappage scheme accounting for over 20% of them.
“We have seen additional demand created by the extension of the scheme and customers wanting to avoid the VAT increase planned for January.
He added: “Encouragingly, there has also been an increase in demand in the fleet and business sectors, which will be critical in sustaining recovery next year.”
'Car sales figures confirm the most significant year-on-year monthly gain for 2009.
"The vehicle scrappage scheme has played a vital role in the return of consumer confidence,' said Sue Robinson, director of the Retail Motor Industry Federation (RMI).
* To view manufacturer October sales and year-to-date figures click here.
* To view regional registration figures click here.
* Scrappage totals: click here.
* For full analysis see AMe on Monday.
Registration data sourced from the SMMT