Business registrations also hit a record volume in 2003, taking an unprecedented market share, while relatively subdued fleet demand strengthened in December, when registrations were up 9 per cent year on year.
Vauxhall displaced Ford to take first place in the fleet sector with a 20.8 per cent share, supplying 221,806 cars against Ford's 213,947.
The supermini is now the largest market segment having risen more than 75 per cent over the last 10 years, to take a record 33.9 per cent market share in 2003.
Superminis also dominated the top ten best-sellers list, taking four of the top six places. The Focus retained its top spot for the fifth consecutive year.
Diesel volumes reached a record 704,637 units in 2003, representing a 27.3 per cent market share. The Mondeo was narrowly 2003's top selling diesel car.
Renault moved up into third place for the first time in 2003 with 189,427 sales, displacing Peugeot, and was also the leading marque in Scotland for the first time.