Almost 430,000 new cars were sold nationally last month - the biggest September total in a decade - new figures have shown.
The Society of Motor Manufacturers and Traders (SMMT) reported sales reached 425,861, which is 5.6 per cent up on the same time last year and represents the 31st consecutive monthly increase.
Almost two million new cars have been sold so far this year - 9.1 per cent up on the same period last year, showing the continued success of the British motor industry.
September is usually a busy month for car sales because of the new registration plate.
SMMT chief executive Mike Hawes said: “September’s strong performance underlined the continuing robustness of the UK new car market, particularly in the context of last September’s bumper volumes.
“Demand for the new 64-plate has been boosted by intensifying confidence in the UK economy, with consumers attracted by a wide range of exciting, increasingly fuel-efficient, new cars.
“In the months since March - which saw an 18 per cent jump in registrations - the growth has shown signs of levelling off as the market starts to find its natural running rate.”
Best sellers in September were the Ford Fiesta, Ford Focus, Volkswagen Golf, Vauxhall Corsa and Volkswagen Polo, making up the top five.
The UK switched to a twice-yearly plate change 15 years ago, with the arrival of the T-plate in 1999. Previously, plate changes happened once a year, in August.
Number plates now change in March and September, with consumer demand for the latest plate meaning that these months typically account for a third of the entire year’s registrations.
From 2004 to 2013, March averaged just over 400,000 cars per year, with September slightly less at 380,000.
But the SMMT said that, following an 18 per cent surge in sales in March, the more moderate increase last month indicates that demand is starting to level off.
Richard Lowe, head of retail and wholesale at Barclays, said: “The heady cocktail of a new plate change, great finance deals and the appeal of increasingly fuel-efficient cars resulted in September being another strong month for new car sales.
“Consumers are also benefiting from stable residual values, enabling them to trade in their old cars for shiny new models at a similar monthly cost.
“While the market is likely to balance out over the final few months of the year, 2014 is destined to be another success story for dealers and manufacturers.”