What's all this about?

Less fuel stops for your driver, or you, if you happen to be driving yourself, as you might well be in the Bentayga. Bentley has finally answered the question we've all been asking for years, and popped a diesel engine behind its flying B badge. It's in the Bentayga for now, the 4.0-litre triple-charged turbodiesel promising the massive torque outputs Bentley drivers expect, but with greater fuel range (620 miles), allowing it, says Bentley, to reach Verbier's slopes from London without having to stop.

Useful, but noisy?

That sort of range is undeniably useful and it comes, Bentley says, with no penalty in on- or off-road ability. It's not quite as quick as its W12 relation, but then the 435hp it delivers is enough to reach 62mph in just 4.8 seconds and 168mph, which is 0.1 seconds and 13mph quicker than the previously fastest diesel SUV in the world, the Audi SQ7 TDI. Annoyingly for those Audi engineers at Ingolstadt, the British motorcar achieves its class-leading speed by borrowing it V8 diesel engine from the car it beats. It's a cleverly engineered unit, with twin sequential variable vane turbochargers aided by an infill electric turbo. That allows the V8 to produce a whopping 900Nm from just 1,000rpm. It's a surprisingly tuneful diesel in its Audi setting, too. Under the Bentayga's bonnet the engineers at Crewe will have busied themselves to make sure that the Shire horses 1,740 clattering hooves contained within are muted to the soft delicate pads of a fine dressage horse with slippers on.

A stealth diesel, then?

We expect so, though we'll only be sure when we get to drive it. What's certain is it'll be cheaper to run, as if that really matters in this class. Emissions output is down from the 296g/km of the W12, to 210g/km, which represents an initial tax saving of £460 and £215 a year thereafter, which would be a nice little bonus to one of your staff. Outwardly, nobody will know if you delete the 'V8 Diesel' badges at the bottom of the front doors and select a different grille than the standard black and chrome surrounded one that comes with it.

Now the seal is broken?

Now Bentley's gone and delivered what we've all been asking about for ages, it does leave us asking whether it'll be used elsewhere. Seems inevitable, doesn't it? The diesel V8 engine would work well in the Continental range, for example, which is long overdue a refresh.