Road Test: Mercedes-Benz M Class ML250 CDi BlueTEC SE 5dr Auto

Finally, Mercedes has sussed the M-Class. This is the car that started the whole posh SUV boom with the original version back in '97 (the slabby one). A year later, the first BMW X5 came along (the slabby one), and together they began splitting opinion like two-tonne cleavers. They've been equally loved and rebuked, but there was always one thing to agree on: the Merc was a total clunker. It cornered like a trifle, and it was so poorly made that Clarkson once inserted a whole finger into the gap between the lights and the bumper. Luckily, the designers made a much better effort in 2002, and an even better one with this shiny new version. That didn't take long, did it?

So this one's entirely new, and although it started life on the same drawing board as the also-new Jeep Grand Cherokee - they were part of the same company before Fiat relieved Daimler of anything Jeepish - the similarities are limited to a bit of sub-frame and some floor. Otherwise, it's unmistakably a Mercedes-Benz - from the star on the grille (now a similar size to a human head) to the boutiquey cabin. The basic M-Class outline remains, including the wrap-around rear screen and slanted C-pillar, though the whole car is now a bit larger.

The big changes are ones you can't see. Let's start with the entry-level ML 250 CDI, because it has a 2.1-litre, four-cylinder diesel engine, and, until now, cars like this never had those. It's not as effortless as the 350 CDI V6 diesel, but 204bhp is just enough to shift the considerable mass around without running out of breath, and the auto 'box is seamless and smooth. It has AdBlue tech - urea is added to exhaust gases to neutralise noxious fumes - so it's ahead of the game on Euro emissions standards, and anyone with a clichéd loathing for SUVs will have to dream up some new argument once they see the CO2 figure of 158g/km.

If there's one thing the last M did well, it was comfort. This one's no different, and it now has active anti-roll bars - an optional extra - to help it ride even better by reducing choppiness over lumpy roads. You're better off choosing this over the optional active ride system, because it's more useful more of the time, and you can sense it smoothing out the tarmac. It also helps it clamber around rocks and boulders, something we tried with success on the test route, and when combined with the optional off-road pack, the M could happily chase a Land Rover over some geological weirdness.

But, whatever. You might have an occasional interest in getting it grubby, but what you really want is a big SUV without a correspondingly hefty tax or fuel bill. So keep it simple, and take the 250. Merc hasn't released prices yet, but apparently we should expect it to be quite a lot less than the price of a basic £45,055 X5 3.0d SE. Cheaper, but not much poorer.