Like a good many motoring publications, BBC Autos has heaped no small amount of praise on the Bentley Bentayga. With a 6-litre petrol W12 engine producing 600 horsepower, the off-roader from Crewe has claimed the title of the world’s fastest SUV. For 2017, a new model joins the family: a diesel. It’s not only the first diesel-powered Bentayga, it’s the first diesel-powered Bentley. The diesel-sipping Bentayga makes use of a turbocharged 4-liter V8 -- a revised version of the engine in the Audi SQ7 sport-utility vehicle -- that produces as much torque as the 12-cylinder petrol engine, but manages to be both more fuel efficient and cleaner.

Top Gear’s Ollie Marriage recently had the opportunity to sample the Europe-only Bentayga Diesel. How does it compare with the petrol model? “It’s every bit as effortless, but much more efficient,” he writes. And yet, this is a surprising time for a carmaker to unveil a new diesel model. “The mayors of Paris, Madrid, Athens and Mexico City want diesel banned by 2025, writes Marriage. “A London ULEZ (Ultra Low Emissions Zone) is planned to come into force in September 2020, likely to charge all diesels £10 to drive into the city.”

Below, find some of Ollie's thoughts on the world's fastest (and priciest) diesel SUV.

On its engine
I’ve never driven a smoother diesel. There is noise, or rather an awareness of noise, but only in the same way that you’re aware of a W12 — it’s a background hum. Unless you’re standing outside, where there is a detectable diesel clatter. Even then it’s not offensive, though. Inside, the engine note isn’t as deep and woofly as the W12’s, but there’s no vibration, no intrusion, no rattle or clank. The power delivery and speak-softly-carry-big-stick character fits the Bentayga every bit as well as the W12. I reckon that if you didn’t tell your passengers, they’d never guess the Bentayga was diesel powered.

On its performance and efficiency
There’s a lot of clever technology packed within, not least a triple-charged 4.0-litre engine. That develops 429bhp and 664lb-ft of torque, the latter from only 1,000rpm. And yes, you did read that right: maximum torque at 1,000rpm. 0-62mph takes 4.8secs and top speed is 168mph. It develops as much torque as Bentley’s W12 petrol Bentayga and makes it available 350rpm sooner, and although it isn’t quite as startlingly rapid on paper (the numbers for the W12 are 4.0secs to 62mph and a 187mph maximum), it makes up for that by being much cleaner (210g/km of CO2 plays 296g/km) and more efficient (35.8mpg on the combined cycle for the diesel, against 21.6mpg). That makes the Bentayga diesel the cleanest, most efficient Bentley ever.

On its design and aesthetics
There’s something about the proportions that jars. It’s better inside, where the quality is unimpeachable, the materials majestic. There is no other SUV, not even a Range Rover, that comes close to the tactility the Bentayga offers. That said, the cabin is complex, arguably over-burdened with electronics — but isn’t everything these days? It’s logical enough, mind you, and although I wouldn’t describe rear space as palatial, rear seat passengers aren’t going to complain too much. But given the exterior dimensions, you expect a bit more. Boot space as well as rear legroom.

On its road manners
The basics of the driving are fantastic. It’s a silent cruiser, steers precisely enough and the active anti-roll is uncanny at keeping the body level and getting the best from the hard-pressed (literally) tyres. Just don’t think it’s a sports SUV in the mould of a Cayenne, because it’s not. This is a GT SUV. It’s every bit as responsive and sporting as the W12. Which is to say not very, but also to point out that the diesel is by no means the weaker choice. You need to know that the anti-roll system isn’t standard here, and you have to have it.

On its price
It starts at £135,800, which is £24,400 less than the W12, potentially opening up the Bentayga to a (slightly) less affluent market. In the UK Bentley believes it could account for 50 per cent of sales — which incidentally, are very healthy at the moment. Bentley expected to sell 3,600 Bentaygas this year, but has actually produced 5,600.

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