“We've exited retail business in the UK because it was going down the price-not-content route,” said a Trafficmaster spokesman. It's starting by concentrating on CV fleets and manufacturers where it believes built-in systems are rare. Citroën is already on board and fits the Smartnav system as standard to its new Relay and Dispatch.

“One possibility is an HGV-specific product that can take into account low bridges, sharp turns and the like. We'll have this service available later this year,” said the spokesman. The idea came from the company's US arm, where it's heavily involved in truck fleets.

“In the US we've lowered fleets' journey times and mileage by 13 per cent on a before/after basis of using Trafficmaster. Imagine what that could do for a UK fleet's running costs.