However, total year-to-date registrations were up by 2.2% to 1,521,225 units.
Christopher Macgowan, chief executive of SMMT, said: “Since the introduction of the twice yearly plate-change prefix, August has vied with February for the dubious honour of being the smallest volume month for new car registrations. This year August was down just 312 units compared to 2006 and at 77,649 units, was slightly above the February figure.”
The Astra topped the best sellers list for the second consecutive month, helping Vauxhall to remain the top selling manufacturer for each of the past three months. The Ford Focus continues to be the UK's top selling model over the year-to-date.
Supermini volumes dipped in August, but overall remain positive for the year-to-date, up 4.5%.
Diesel-powered car registrations rose for a sixth successive time in August. Their market share moved up to 41.4%, the highest rate of the year, and well above the 38.9% share taken a year ago. Year-to-date diesel registrations rose by 6.5% to 595,033 units. The Ford Focus remains the best selling diesel model in 2007, although the VW Passat was number one in August.
Sue Robinson, director of the RMI National Franchised Dealers Association (NFDA), part of the Retail Motor Industry Federation (RMIF), said: "September's dominance of the new car market during late summer means that August is a quiet month, but it is encouraging to see that the market has remained stable in the run-up to the September number plate change."
Also today, the Bank of England announced that interest rates will stay at 5.75%. Robinson believes that consumer confidence will continue to benefit from this: "Holding the interest rate at its current level may help car sales. "Interest rates need to stay at the current level for the time being, in order to allow for a long-term market stabilization."
UK new car registrations
Top 10 best sellers