Mercedes believes its sole-supply contract with cut-price rental firm EasyRentaCar will lead to a surge in demand for the A class.

A Mercedes spokesman said the deal, which involves 2,000 of the cars, would bring in additional business because “people will have the chance to try out the car”, but he stressed that Mercedes had staggered the roll-out to protect residual values.

“At the moment EasyRentaCar has 700 variants including different engines and colours. We won't flood the market - and we don't expect any adverse effect on residuals,” he said.

The A-class has become the UK's fastest selling Mercedes-Benz, retailing 23,000 units since the October 1998 launch, with retail buyers the largest proportion. Mercedes expects to sell more than 16,000 next year.