Motoring: The first faltering steps of the Baby Benz

How the mighty fall - or, in this case, roll. Mercedes-Benz, a motoring exemplar that stands for solidity, safety and "engineering like no other car in the world", has had its latest model exposed for tipping over at only 40mph, and for being about as steady as Jeffrey Bernard after a session at the Coach and Horses. The new A-class - the "Baby Benz" - has been an unmitigated PR disaster for a company which hitherto has been as cushioned from bad publicity as most of its owners are from poverty.

While Mercedes undoubtedly has a problem, and the world's media enjoys some schadenfreude at the expense of Germany's biggest company, it's worth putting things in perspective. A Swedish motoring magazine tipped an A- class during severe "moose avoidance" tests on a frozen road in Scandinavia at 40mph. What's missing, from most of the accounts, is that the car had five people and 800lb of luggage - equivalent to three Mike Tysons - in the boot. In a car the size of a Metro, that may be a little over the top. None of the five passengers suffered more than superficial injuries.

Later, for the benefit of photographers, another A-class was blasted around cones on a dry track in Germany and got up on two wheels. Yet there are allegations that - to get the spectacular shots - the car was fitted with odd-sized tyres to encourage a flip.

Before the Swedish "moose test", an estimated 1,400 journalists had tested the A-class and, as far as I'm aware, none had criticised the car's stability. The TUV - Germany's equivalent of the AA - commended the car's handling. Equally, Mercedes' own test drivers had racked up 3 million test miles using 500 different cars. Critically, none of Mercedes' testers had done the "moose test" - a major oversight, as this is normally standard practice, despite the fact it's meaningless outside frozen northern countries. Reports that Mercedes has made engineering cut-backs, to compete with rival mass makers on price, probably hold more than a grain of truth.

For me, the A-class fiasco raises many issues. Is it realistic to condemn a car as dangerous, when it fails an unusual manoeuvre unlikely ever to be reproduced in real-world conditions? A number of cars on sale right now would probably fail a similar assault - or at least display unnerving instability if packed to the gunwales and swerved violently on frozen roads.

Which cars? Simple - any which are unusually tall. The law of physics is immutable. A tall car with a comparatively small road area - such as many smaller MPVs and 4x4s - is likely to roll over, in extremis, at speeds which would see normal saloons or coupe's stay on all fours. Can you imagine how a London bus would fare in the Scandinavian moose test? Yet tall and usually space-efficient cars have many attractions - not least, like a bus, that they can carry many people while occupying only a small road area.

The A-class has now been temporarily withdrawn from production, while various chassis modifications are made. It is probably an over reaction by Mercedes, as much PR stunt as a serious attempt to re-engineer the car.

It may also not be enough. The "fixes" are still largely superficial; this small and tall car will still be less stable, on the limit, than a normal saloon. And come February, when the A-class re-emerges from the factory, new bill of health proudly attached to windscreen, motoring journalists around the world will all be doing their "moose tests", photographers ever present, hoping to get some great footage of the A-class on tippy toe. If they succeed, the baby Benz may even be stillborn. And one of the cleverest new car concepts - even if its execution this time is flawed - may be lost for years.