Top Gear's Big Road Test: 1,400 miles in a Bentley Bentayga

A diesel Bentley. I’m cursing the idea right now, but not due to misplaced nostalgia. Nope. The Bentayga diesel has inspired the boss back at TG Towers to lay me down a seemingly impossible task: driving one back home from the Marbella press launch on just two tanks of fuel. That’s 1,400 miles, if you’re wondering.

The theory is sound. Bentley knows that its owners don’t require 35mpg economy, but that there is luxury in making as few monotonous fuel stops as possible. The reality, though, is that I’ll need to squeeze 700 miles from a tank of fuel, when Bentley’s claimed range is 621. Impressive for a 2.5-tonne, 429bhp V8-engined SUV, but not enough.

Photography: Stuart Price

This feature was originally published in issue 291 of Top Gear magazine

Upon brimming the 85-litre tank as the sun sets on southern Spain, I’m immediately crestfallen: the range is reading 730km. Or 454 miles. I’m picking the Bentayga up off the back of being manhandled by journalists, though, and the reading is probably pessimistic after several days of “testing”. Sure enough, the first hour out of Marbella and onto the motorway goes by without the number dipping. I’ve made a conscious decision to travel at the speed limit, too. There’s no luxury in crawling along in the slow lane.

But as we approach our Seville hotel, the range drops to 720. Then 710. It’s falling neatly with the distance, but it’s doing so way too early in the journey. Against better judgement, I drop below 60mph and tuck into the inside lane. I even elbow photographer Stuart into turning off his massaging seat, though spying his seven tonnes of camera gear (approx.) in the rear-view mirror, it’s a vain gesture.

Whatever speed you travel at, the Bentayga is serenely quiet. It shares its 4.0-litre twin-turbo V8 with the Audi SQ7, but uses it in a gentler tune, without any sound actuation. While the Audi pretends it’s a V8 petrol, the Bentley gives you the impression it has no engine at all. Seriously: unless you force the eight-speed automatic gearbox to kick down a few gears, then everything from aloof acceleration to 70mph-plus cruising is all but silent.

The flip side is that you’re a bit desensitised, and it’s all too easy for speed to creep up with even the slightest twitch of your foot. Sticking to 56mph straddles the fine line between torture and plain impossibility. When a beaten-up Dacia Logan overtakes as if we’re a moped, I return to the 120kph (75mph) limit.

We’re up against it, but inspiration comes with a sunrise visit to a wonder of efficiency, the PS10 solar power plant on Seville’s outskirts. It might sound beardy, but it’s staggering: a field of hundreds of mirrors project the sun’s rays at a “power tower”, which converts them to electricity. Minutes after the sun has poked its head above the horizon, dozens of rays can be seen with the naked eye, connecting the ground with the tower’s peak. It’s genuinely astonishing.

It’s also a perfect visual pep talk to get my arse in gear and drive home efficiently, like the boss demands. We venture north, but no matter how smoothly I’m driving – and how little of the LaFerrari-matching 664lb ft I’m actually using – the range is shrinking too hastily. After a few pictures at Corta Atalaya, Europe’s largest open-pit mine, Stu informs me where he’d like to shoot sunset. It’s a hill in Valdezcaray, in Spain’s north-east, barely a detour from our route. In fact, it shortens the distance. But as I plug the location into the Bentley’s nav, the 7pm arrival time – an hour after sunset – tees up a fateful decision.

What happens next, dear reader, I’m not proud to retell. With the choice between bringing back a cool photograph or following the editor’s orders – and the brilliantly twisting A-461 separating me from either – my hand slips in the direction of the Bentley’s driving mode selector. It knocks the car into Sport as it does so and we head away from the mine with quite a lot of torque bombastically awoken from its slumber, not unleashed since the last journalist climbed out. I’ll get a verbal warning for this.

My first counter argument in the disciplinary meeting, though, will be that I’m testing the car. Despite its diesel power, rotund weight and wanton luxury, there’s still some handling beneath the Bentayga’s skin. It doesn’t shrink around you like a Porsche Cayenne, or even the SQ7. But the steering is nicely weighty, and it grips and turns unthinkably well for something so large. There are some clever electronics to thank, in the shape of an optional active anti-roll system. With the car in its feistiest mode, you can really sense its effect.

We’ve cut 20 minutes from the ETA as we return to the motorway, with all but the rest of the day a 120kph whisper. Stu has promptly fallen asleep, though not before reactivating a full-strength lumbar workout. It seems he’s given up on the fuel-sipping mission, too. And with gloomy inevitability, the refuel light pings on. The barren Spanish landscape is enlivened only by copious birds of prey, ready to gnaw on hopeless Brits who’ve ran out of diesel, so I pull in for our second brimming of the tank. It totals 72.3 litres, after 448 miles at 29.1mpg. We’re 13 litres shy of filling the tank from empty, proving you’d have to play some serious fuel-light roulette to have any hope of 621 miles per tank. My second point when I’m grovelling to the boss.

Though the range has tumbled quicker than we’d like, the miles have not, and we arrive at the foot of Stu’s “hill” – I’d err more on the side of “small mountain” – long after sunset. The gravelly hairpins leading there should be sign enough this isn’t the place for a £177k Bentley (with options), and when the road runs out, replaced by two eerie tyre tracks in the rocky, snow-speckled hillside, I know we should turn around. Problem is, my rebellious streak has been provoked. Again my hand falls onto the drive select dial, knocking us into Mud and Trail mode and the ride height to its max, and we’re soon clambering slowly over terrain no Bentley has ever seen. Oh God, now it’ll be a written warning.

To warrant my fate, the view that greets us at the top is utterly… um, cloaked in darkness. But that’s because we’re looking ahead. There’s a magical sky of stars above us, and Stu gets an even better shot than he’d hoped. Our crawl back down is a doddle: the Bentayga makes ludicrously easy work of off-roading, and with Hill Descent Control activated, we slither back to civilisation in as much comfort as we conquered Spain’s highways. I’m deeply impressed.

Beds are awaiting us in Bordeaux, and an hour from sleep, the fuel light is back on. I decide to eke out some more miles this time, and pull in when the range is almost zero. Yet the Bentayga still only takes 77.5 litres, having covered a spookily identical 448 miles. I think I’ve found its realistic range...

So yes, we’re barely in France and I’ve officially failed. Time to enjoy the run home, then, as I’m not sure I still have a job. There’s an alluring detour between us and the Eurotunnel, in the shape of a little town called Le Mans. You might have heard of it. I’ve never been outside of 24-Hour weekend, and just to ramp up the “ghost town” vibe, there’s deep mist pierced only by bright blue and yellow kerbing, tantalisingly marking out the bits of circuit that are actually public road.

Driving them should be on every car geek’s bucket list. Blasting a Bentley down the Mulsanne Straight, besides being a colossal cliché, is also a good opportunity to assess its drivetrain. Power is plentiful, though while Bentley claims this is faster than the SQ7, I’m not sure it feels it. But then Audi diesels have form in this part of the world. Get too impish with the throttle, and the soundtrack betrays the Bentayga’s fuel source, too, though it’s not clattery or unpleasant. It’s just evidently not petrol. Keep it to yourself, but I think I’d enjoy Audi’s sound effects software in here.

Our journey back to England, and a final photo on Margate’s despondently quiet strip, is punctuated by one more fuel stop. The final few hours are as blissfully quiet as the rest, and as we complete the inaugural “1,533 Miles of Marbs to Margs”, the final reckoning is three-and-a-half tanks of diesel, slurped at 28.1mpg.

Alright, I’ve failed at my task. Spectacularly. But I don’t think the Bentley has failed at its. Going 621 miles between fuel stops may be improbable, but in all other areas, the Bentayga makes shunning petrol as plush as can be. It’s even proved fun on a circuit and faultless off-road. If I have lost my job, it’s been the most luxurious sacking imaginable.