Mini bosses are “confident but cautious” after latest sales figures slumped by almost 18 per pent.

Statistics compiled by the Society of Motor Manufacturers and Traders (SMMT) show 753 of the Cowley-built cars were sold in the UK during August, compared to 918 for the same month last year.

Mini director of communications Graham Biggs said: “This remains a difficult economic environment and there remains a lot of economic uncertainty.

“People are concerned about factors such as the rise in VAT in January which may affect the general cost of living.”

But Mr Biggs said he is upbeat about the future with the launch of the Austrian-built Countryman model on September 18. Just 2,500 of the new cars, which come with optional four wheel drive, have been put on sale this year and all have been snapped up in advance.

And he added that the further expansion of the Cowley plant to accommodate the Coupe and Roadster models in 2011 and 2012 will help boost sales in the long-term.

He said: “The market remains difficult but the Countryman will boost volumes and we are very positive about that.

“The Government needs to provide stability that allows people a firm base on which to make decisions.”

In the year to date, Mini sales are more than 19 per cent ahead of last year with 25,523 cars sold in the UK and the car occupies ninth spot in the top ten best sellers for 2010.

Nationally, registrations fell 17.5 per cent in August to 55,305 units compared with 2009 which was boosted by the Government’s scrappage scheme that offered drivers £2,000 towards a new vehicle, provided they traded in their car of more than ten years old.

SMMT chief executive Paul Everitt said: “Conditions will remain challenging through the rest of the year.

“The industry enjoyed a better than expected first half of the year and, despite the difficulties, SMMT is forecasting that new car registrations will close just ahead of 2009 figures.”

• The Ford Fiesta was the best selling model in August and over the course of the year.