New Range Rover draws a line in the sand MORNING in Marrakesh, and the traffic is at its most mental. Eight lanes"-worth of trucks, cars, mopeds and livestock scrap for two lanes of asphalt. From all points of the compass they come, at all speeds, cutting in front, alongside and behind. The ancient city walls that kept desert tribesmen at bay for centuries can't do anything to contain the clatter of diesel and two-stroke engines. And the horns! The endless horns. It doesn't matter if you've rolled into town in the driver's seat of a decades-old Merc or on the back of a donkey - nobody has right of way here. At roundabouts, pick your moment, press the accelerator and pray you don't hear a crunch. At first glance, it's not the sort of place you'd choose to take a brand new Range Rover for a quick spin but, if anything is going to convince the locals to keep a safe distance, it's the site of a terrified driver at the wheel of a very big car with foreign number plates. It works. Despite nearly coming a cropper at a couple of vaguely signposted crossroads, I survive my first taste of a North African rush hour unscathed. Glad to be alive, but glad I got the chance. With the city behind me, I make tracks for my next stop, a village in the Atlas Mountains, perched twice as high as the peak of Ben Nevis and accessed by a track barely wider than the car I'm in. It sounds daunting but, after what I've just survived, I'm ready for anything. Which is just as well, since the Range Rover will have to navigate a three-mile stretch of river bed before we arrive at the foot of the mountains. Yesterday, we drove it over sand dunes the size of castles, up a rock-strewn hillside and through a gorge with one, sometimes two, wheels off the ground. In 30C heat, it never broke sweat. Yes, the fourth-generation Range Rover is here. Given the extent of its go-anywhere, conquer-anything capability, you can expect to find it there and everywhere as well. It's bigger than ever but, thanks in part to an all-aluminium bodyshell, weighs an astonishing 420kg less than its predecessor. That's five reasonably-sized adults, or three Americans. As a result, performance and economy are boosted and, for the first time, UK buyers can now choose a 3.0-litre, six-cylinder diesel engine to spirit their Range Rover along. That crash diet means the small diesel gives the Range Rover the same turn of speed the 4.4-litre V8 diesel used to without gulping nearly as much fuel. The V8 diesel now boasts performance on a par with the 5.0-litre supercharged petrol cars of old and the supercharged Range Rover moves in a manner that will make you question everything you learned in physics class. All engines are now paired to an eight-speed automatic gearbox. However, this being a Range Rover, performance is only part of the package. There's rival-smashing off-road ability, impeccable on-road manners and regal opulence to factor in as well. There's also a new look. It's evolutionary, rather than revolutionary, testament to how right the first Range Rover looked more than 40 years ago. The swept-back front headlamps and spangly rear-light clusters are the most obvious changes, but look a little closer and you'll notice the distance between the front and rear wheels has grown. Gills on the flanks are for decoration only, since the engine now breathes via a series of funnels hidden away between the wing tops and the bonnet. This means the Range Rover can now paddle in water 90 centimetres deep - 20cm deeper than before - without spluttering. The Range Rover's cabin is a wonderful place to seek refuge from sub-Saharan dust and heat, or the glaur of a Scottish November morning. In the front, the seats are large and comfortable, the dashboard is less cluttered than before and the view ahead is commanding. Deep door pockets, two gloveboxes and four Coke cans"-worth of fridge in the console between the seats are just what you need for a trans-African daunder. The Range Rover's terrain response system now has an automatic mode, which allows the car to sense the conditions for itself and adjust ride heights, throttle settings and gearing accordingly. Don't ask me to explain, for I haven't got a clue, but it works. But it's in the back where the biggest change has happened. That stretched wheelbase means almost 12cm more legroom for rear passengers, and getting in and out is easier too. An optional centre console replaces the middle rear seat and turns the Range Rover into a road-going executive jet for four. On road, the benefit of that weight-loss programme can be felt in the way the Range Rover acquits itself in the corners. You know it's a big car - its motto ought to be "here comes another car, breathe in" - yet it never feels less than nimble. Braking distances are reassuringly short as well, as scores of still-living stray donkeys, camels, dogs and a tortoise will testify. The suspension does a magnificent job of soaking up the bumps, be they ripples on the road or fist-size rocks on tracks where peering over the edge automatically invalidates your clean underpant warranty. While the Range Rover convoy pauses for coffee almost 9,000 feet up in the High Atlas, drivers swap tales of derring do. Well done us, well done the Range Rover. Then a man on a moped wobbles into view. He has followed us here, on the same rocky track we've just conquered, in the hope of selling us some jewellery. Having deflated a dozen egos, he scoots off again, empty handed. On the motorway back to Marrakesh, the Range Rover whispers along at 70, its tacho showing just 1,400rpm in top. Every so often, a Transit van, its axles groaning under the weight of livestock in the back, on the roof rack, in the passenger's seat, meanders into our lane without warning. Radar-assisted cruise control, which can bring the car to a standstill should the need arise, is a blessing. The new Range Rover. It's as nimble as a mountain goat, and as posh and potent as a brand new Bentley. But it can't teach Moroccans much about road sense. CAR Range Rover PERFORMANCE Max speed 130-155mph; 0-60mph 5.1-7.4secs MPG 20.5-37.7 combined