Motorway services are charging up to twice as much for meals as supermarkets, reports a survey commissioned by traffic information website www.keepmoving.co.uk.

Rip-off motorway meals won’t come as a surprise to Britain’s hard-pressed motorists, but the survey has also revealed a strong regional pricing bias, with drivers in the south and west paying most.

Six of the top ten most expensive services are on the M4 - five of these are run by Moto - with Reading topping the list.

Buying sandwiches, crisps, chocolate and bottled water for four costs £26.68 there – against a typical price of £12.24 for the same items at a supermarket.

The only motorway outlet that comes in for anything approaching praise is M&S’s growing chain of motorway ‘Simply Food’ outlets, which charge the same across the country and also undercut other food vendors on the same site.

The survey was commissioned by www.keepmoving.co.uk. The site offers a free service to help users find supermarkets within a one-minute drive of motorway and ‘A’ road junctions.