“We've heard that there are instances of this happening, people have contacted our customer relations department to tell us so, and we're looking into the situation,” says a company spokesman.

Ducato-based motorhomes seem to be particularly afflicted by the problem. Like Citroën's Relay, Peugeot's Boxer is almost identical to Ducato so far as its basic design is concern and a spokesman suggests that the supposed fault is more likely to be clutch than gearbox related.

“It's not something that's been raised with us recently, but it's something we've seen in the past and it usually turns out to be clutch judder, possibly caused by a worn plate,” he says. “It's something that can particularly afflict chassis cabs that have had large, badly-specified, bodies mounted on them that turn out to be heavier than the clutch can cope with once they are fully laden.”

“So far as I'm aware there has been no indication that there is a reverse-gear problem with Relay,” says a Citroën spokesman.