The SMMT has been doing its best to talk up the key September 55-plate market but dealer groups expect the month to be in step with the year-to-date decline.

There is little prospect of this month rescuing 2005 despite a huge marketing spend by volume manufacturers. There are also growing doubts among dealers about whether the September plate-change month is still a powerful catalyst for the market.

The SMMT says new car buyers are “all set for the 55-plate rush” and forecasts around 420,000 registrations, which would make this the second busiest month of the year after March.

Manufacturers have been forced to offer three or four years free credit to try to stimulate interest as they battle for market share. Car supermarkets and other traders are ready to snap up discounted units from brands needing to hit volume and market-share targets.

Ashley Winter, chairman and managing director of Patterson Ford, Newcastle-upon-Tyne, says: "The market continues to be tough and we did not see a stampede for sales at the beginning of the month."

Alan Pulham, motor industry consultant and former RMI franchised dealers director, expects September sales to be 5% or 6% down year-on-year. “The problem is many buyers regard their three-year-old car as ‘new’. They are not interested in buying a 55-plate model,” he says.