In a recent vehicle test in a major car magazine which was testing wet weather braking in 6 vehicles one of which was the Range Rover Sport. The task was to stop on a wet road as quickly as they could. They then say " Here, 4 wheel drive is no use whatsoever as none of the wheels is driving" If somebody could explain this I would be grateful. I thought that even in the Sport as you slow down however quickly the gears drop down until you are stopped and in first therefore as you are in a gear the wheels must be driving,

Thanks John

The transmission will downshift as you slow down to stop the engine from stalling, but other than a small amount of engine braking it won't be doing anything useful. The majority of the braking effort is done by the wheel brakes, and every car has four-wheel braking.

As FlyingPete says, if you slam the brakes on then all vehicles have similar braking. If you are descending a snow covered road or a or a muddy track, then engine braking through 4WD, low box, hill descent control (in modern vehicles) etc gives you a massive advantage over a 2WD vehicle. Their test is not testing the capability of a 4WD

If I understand correctly, braking under wet weather conditions is all about:
Vehicle mass (and distribution thereof), velocity, contact surfaces, i.e. tyres and road. And to a certain degree, the efficiency of brake response and brake balance.

The engine or the fact that it is 4WD has no real affect. To put it another way, if all of the cars tested had the same mass, tyres and brake set-up, the test being conducted is about the ABS or similar traction control system integrated in the vehicle's computer. If you're slowing to a stop, there may be an element of engine braking as per FlyingPete's comment.

There are better ways to stop in the case of snow/ice as Al203 rightly points out; and IMO understanding the way your vehicle works and a manual technique is much better than a blind computer that can't see the tree 10m in behind you as you hurl down a hill backwards

Alm.