LONDON (Reuters) - New car registrations in Britain fell an annual 18.6 percent last month to record the market's weakest August since 1966, a survey showed yesterday.

The Society of Motor Manufacturers and Traders said there were just 63,225 car registrations last month.

"The August market was the lowest since 1966 and accounted for a quarter of the fall in volumes over the year-to-date," the SMMT said. "The last three months account for 89 percent of the drop."

August is traditionally a quiet month as consumers wait for a change in number plates in September before buying new cars. Nevertheless, the fall is also indicative of the strains on British consumer finances as a housing market bubble bursts.

"Sharply deteriorating car sales is a further clear sign that consumers are increasingly cutting back on their spending," said Howard Archer, an economist at Global Insight.