Registrations last month reached 451,642 units, making it the best sales month since March 2004.

Latest figures from the SMMT show that the UK market proved to be surprisingly resilient, despite the impact of the global economic slowdown.

New car demand rose by 2,355 units year-on-year as the new number plate proved more popular than expected.

“March continues to be the biggest month for new car registrations and this year has proved to be better than anticipated,” said Paul Everitt, SMMT chief executive.

“We expect 2008 to be a challenging year but registrations to date are in line with industry forecasts.”

The strong March registrations brought quarter one volumes on a par with 2007's strong level, prompting the SMMT to announce it would review its annual prediction of 2.345 million units later this month.

Consumer spending remained robust as the private sector recorded a modest dip of just 1.4 per cent to 222,788 units – equal to a 49.3 per cent share of the monthly market.

Fleet and business sales increased by 2.6 per cent and 1.8 per cent respectively to help March record its marginal increase.

Demand for diesel cars showed no sign of abating as sales of oil burners rose 7.4 per cent to 182,533 units and a 40.4 per cent share of the market.

While the Volkswagen Gold remained the UK's bestselling diesel model, it was Ford that took the top two spots overall.

The Focus was again the bestselling car in the plate-change month with 21,850 units sold, pipping its stablemate the Fiesta by just under 1,500 units.

Vauxhall was third in the bestsellers list with the Corsa and its Astra model took fourth position. The Peugeot 207 completed the top five.

Despite the unexpected sales boost, the SMMT warned that current economic uncertainty meant it was prudent to prepare for a sudden change in consumer's ability and willingness to sustain new car purchases at current levels.