On a early UK-spec Citroen C3 Picasso the only thing between the passenger's feet and the master cylinder is a thin piece of felt.

It's official: Citroen UK has recalled more than 20 000 C3 Picasso MPVs - because the brakes can be accidentally operated by the front-seat passenger!

Now that lends entirely new meaning to the term “back-seat driver”.

The problem is confined to right-hand drive models, and came about as result of the conversion from the original left-hand drive layout. The brake pedal has been moved to the right but is connected by a linkage to the master cylinder, which is still in its original place on the left.

This is nothing new - the same system was used successfully for many years on the VW Golf - but in the case of the C3 Picasso the only thing between the passenger's feet and the master cylinder is a thin piece of felt. If the passenger presses on the floor in exactly the right place, the brakes will be applied.

A British cleaning company that runs a small fleet of C3 Picassos alerted the BBC's Watchdog consumer show, and they called in expert automotive engineer Mark Brown.

“It's potentially very dangerous indeed,” he said, “because the passenger wouldn't know he's the one activating the brake - and neither the driver nor the people behind would know what was going on.”

That's when Citroen UK issued a recall: It turned out the designers had specified a little plate to cover the hole where the left-side brake-pedal had been but on the first 20 000 or so RHD C3 Picassos that plate got left out - a clear case of the left-hand drive not knowing what the right-hand drive was doing.

The current C3 Picasso was released in the UK a year before it was launched in South Africa - by which time the plate had been re-instated, so the 163 local South African owners of these versatile MPV's can breathe easy.

Nevertheless, when Citroen SA technical boffin Dinesh Govender heard about it on Thursday, he promptly pulled up the carpets on a couple of new Picassos to confirm that the plate was there - and removed one to confirm that, indeed, without it the passenger could inadvertantly apply sufficient braking to slow the car sharply - without the driver or passenger knowing why!