It’s official: Bentley is going big. Two and half billion pounds of self-funded investment will do that to a company.

It has an ambitious rollout programme of building five electric models in five years from 2025. But that doesn’t mean they’re not still developing the current stock. Case in point: the Bentley Bentayga EWB – in many ways the successor to the magnificent Mulsanne (RIP).

As the market for luxury coupés dwindles, the demand for luxury SUVs continues to skyrocket – and not in a NASA-fail kinda way; it’s genuinely in outer space territory now.

It’s been seven years since Bentley released its first Bentayga, and it remains the company’s biggest selling car with 40 per cent of total sales. So what’s the next natural step?

Make it bigger, of course. One hundred and eighty millimetres bigger to be exact. Once you compute that only means 18cm, it doesn’t sound like that much. But ensconce yourself in one of its new airline seats (a £8,395 extra), and you’ll rapidly take a different view.

View is the apposite word here, as there’s so much glass it’s like you’re in an observation gallery. The windows are the size of flatscreen TVs and the panoramic sunroof has been shifted backwards purposefully for the better enjoyment of the rear passengers.

There are very few car reviews I’ve begun as a backseat driver, but this one deserves an exception. If you hadn’t figured it out yet, EWB stands for Extended Wheelbase (not, as a colleague helpfully suggested, Extra Willy Brandishing). It now has more rear legroom than a Rolls-Royce Cullinan or a Range Rover Long Wheelbase, and that new airline seat option offers 22 adjustments and 40 degrees of recline. It’s the kind of space you’d only expect travelling in First Class.

The new EWB also has powerclose doors – meaning the rear doors will shut at the literal press of a button. The next step you’ll want to take is to unclip the remote control unit housed in the rear console. This is a satisfying experience in itself: press the eject button on the haptic touchscreen and the remote extends forward on magnetic arms – offering itself to you. With this in your hands you can control pretty much every element of the car bar the steering wheel.

Enter ‘Relax’ mode, and it will push the front passenger seat forward allowing room for a foot stand to descend automatically in front of you. Sit back, adjust your headrest, and you’d be forgiven for thinking you’d stepped into the Relaxation Room of a hotel spa.

You see, the Bentley designers have done everything in their power to make the rear as calming as scientifically possible. So much so they employed cognitive scientists to help evaluate exactly what makes road travel tiring.

The result in the cabin is cleaner lines and less fuss to distract your eyes. And a seat that literally shifts itself so you don’t have to; with spooky insight it will move around during a long journey to ensure you don’t go numb. This new Postural Adjustment function uses thigh and shoulder pockets, plus additional lumbar massage pockets, to subtly yet continuously change the shape of the seat to ease pressure points around the body.

The seat also automatically changes temperatures in different areas – the first seat in the world to be able to cool your torso but warm your bum, for example. The auto temperature function is rather ingenious in reality; at one point we drove from shade into direct sunlight and the seat reacted with pleasing jets of cool air.

It’s a testament to the exterior designers that all this extra space hasn’t affected the car’s aesthetics. Indeed the swooping haunch line arguably works even better on this model.

It took more than 2,500 new parts to execute the EWB. But how has it affected the drive? Well, as this is a big car, where better to test it than Big Country? And it doesn’t get much bigger than the Canadian Rockies.

The amazing thing about Vancouver is that one minute you can be downtown surrounded by skyscrapers, and the next you’ll have swapped the concrete jungle for a rainforest of 1,000-year-old conifers.

The glorious Highway 99, rebranded in that North American way to the ‘Sea to Sky Highway’, takes you from West Vancouver over the Lions Gate bridge up to Whistler.

The serpentine road follows the coastline of Howe Sound, before winding into the mountains. The views are Middle Earth good – it’s suitably epic scenery for a suitably epic car.

It’s also the perfect place to move into the front seat, too. The launch model comes with Bentley’s much-lauded four-litre twin-turbo V8.

Packed with 542bhp, it delivers a zero-60mph time of 4.5 seconds – only 0.1 seconds shy of a standard Bentayga V8.

The EWB is less than 100kg heavier, and has the most advanced chassis ever fitted to a Bentley. Which you’ll need if you take it up to its 180mph top speed. Impressively, it now has rear-wheel steering so the turning circle is actually tighter than its little brother’s.

All this adds up to a surprisingly sporty package. As with any Bentley, you’ll find that size and stature does not come at the cost of speed.

When you’re ready for a more spirited drive, select Sport mode, and everything tightens up obediently; you get a little more V8 rasp to help encourage your right foot.

When it comes to choosing your spec, you may want to sit down – preferably in one of those lovely rear seats – because there are 24 billion configurations you can choose from. Yes, billion. And that’s before you consider upgrading to a bespoke Mulliner version.

The new Azure range [pictured] is a particularly handsome option, with its old-school vertical pane grille. The Azure package is all about wellbeing – creating as relaxing an environment as possible in something that can travel 180mph. This comes down to the details such as open pore veneers whose softer, satin quality evokes a mood of calm.

The Bentayga was launched in 2015 at the Frankfurt Motorshow as officially the world’s first luxury SUV. Seven years on, the new EWB version has ensured it remains the best.

For more info, see bentleymotors.com