They accounted for 25.7% of car sales last month, up by 6.2% on the same period last year. Year-on-year diesel registrations are up to 73,374 units, a 9.5% increase, figures from the Society of Motor Manufacturers and Traders show.
Experts at the organisation believe diesel will account for 30% of overall sales by 2004 and will be 28% of overall sales, equivalent to 672,000 vehicles, if there are no unexpected changes in the Budget on April 9.
Fleet diesel sales have already reached this milestone, covering 29.52% of the fleet market during February, with total sales of 12,368 units.
Ford was the best-selling diesel manufacturer last month, with 2,142 sales, down 7%, one of five manufacturers that saw sales drop. Big winners last month were Renault, with sales up 51% to 1,366, and Volvo, with sales up 52% to 349.
The Ford Focus remained the best-selling fleet diesel last month, with 875 sales, down 19%. It is the best-selling diesel so far this year, with 2,511 sales, down 16%, followed by the Ford Mondeo, with 2,455 sales, up 7.82%.
For the year-to-date, fleet diesel sales have reached 37,559, accounting for 31.3% of sales.
Ford is the best-selling fleet diesel manufacturer, with 6,283 sales, despite year-to-date demand dropping by 2.79%.
Volkswagen is second, with sales equalling the same period last year, at 5,566, while Vauxhall has so far achieved 5,556 diesel sales, a rise of 5.67%.
Peugeot's sales are down 24% to 4,915, while the biggest winner so far this year is Volvo, with demand up 72.25% to 1,111.