A few years back I had cause to make a short trip onto the local hills in our hatchback. In the twenty minutes I was out there was a snow shower followed by freezing rain, unexpected and obviously no time for gritting. The roads were lethal. I descended into the valley in first gear, foot off the accelerator and with only the most hesitant touch on the brake as every time I went near it the car moved sideways. A fully rigged Landrover Defender appeared in the mirror, a farmer probably, and after after a few seconds of my 'farting about' he pulled out and accelerated past. At the first left-hander he pirouetted off into the ditch. The invincibility of 4-wheel drive has been in doubt ever since.