But official figures show Seat finished the month 1.89 per cent up on April 2001 with a total of 2268 new cars registered. Now, the manufacturer's year-to-date sales stand at 10,658, up 16.85 per cent, from 9121 for the same period last year.

Seat says the delay in registrations is caused because it relies on postal votes rather than using the Driver and Vehicle Licensing Agency (DVLA) Automated First Registration and Licensing (AFRL) computer system favoured by other carmakers.

Most vehicles are registered through AFRL, which allows motor dealers to register and first license vehicles electronically. All other units are registered through Vehicle Registration Offices (VROs).The AFRL system links dealers and manufacturers to the DVLA electronically, so they can register and license new vehicles.

April registrations rose 16.1 per cent year-on-year to a record 208,976 units. Sales are up nine per cent for the first four months to 931,694 units, forcing the Society of Motor Manufacturers and Traders to revise its market forecasts upward by 50,000 to 2.4m units.

Supermini registrations provided the largest boost to April volumes with registrations up more than 20 per cent to 68,409 units. The top 10 sellers featured five superminis: Ford Fiesta, Vauxhall Corsa, Renault Clio, Peugeot 206 and VW Polo.

For the 24th successive month, the Ford Focus headed the monthly best-sellers with 14,076 registrations. Diesel registrations soared 60.5 per cent to 48,537 units with market share at 23.2 per cent compared to 16.8 per cent in April 2001, reflecting the move to low CO2 cars.