NAMED after the Carrera Panamerican road race, Porsche’s Panamera hatchback is the brand’s offering to luxury segment buyers wanting spacious rear seat accommodation and a properly sporting Gran Turismo driving experience.

In this new generation guise, it’s smarter, faster, more efficient and, in E-hybrid form, impressively advanced too.

This being Porsche, we can’t just rely on more efficient engines. We also want more power. So that’s exactly what’s been delivered here.

Almost all British buyers are going to want to consider the new 4S V8 diesel, a 422bhp 4.0-litre unit that puts out an astonishing 627lbft of torque. It makes 62mph in just 4.5s (or 4.3s with launch control) on the way to 177mph.

Alternatively, for petrol people, there’s a 440bhp 2.9-litre V6 in the Panamera 4S and a 4.0-litre twin turbo V8 in the Panamera Turbo, developing 550bhp.

Initially, all Panameras will feature all-wheel drive and a ZF-sourced, eight-speed, dual-clutch automatic.

Underneath, the sleeker bodywork lies a new mixed-material MSB platform that will also be used for the next-generationBentley Continental GT. This is not only more rigid, but is also lighter.

Optional extras include a new, three-chamber air suspension, all-wheel steering and a clever cruise control system that takes into account speed limits, bends and inclines.

The shape is certainly sleeker – and so is what lies beneath. The Panamera is the first model built off the Volkswagen Group’s MSB (Modularer Standard-Baukasten) architecture, a lighter, stiffer set-up than before.

As before, the sloping roofline and large rear pillars mean that rearward visibility is a little compromised. Otherwise, inside, things are also much improved.

Porsche has moved many of the controls to a touch-sensitive panel, with other features accessible via a 12.3-inch colour touchscreen in the centre of the dash – though it’s annoying that you have to prod away at this to alter the airflow out of the central vents.

There are also a pair of configurable seven-inch screens in the instrument binnacle. Here, we’d still prefer a full screen set-up like Audi’s ‘virtual cockpit’.

In the back, as before, there are two sports chairs that position rear occupants for a great view out ahead.

Legroom still isn’t as generous as you’d get in a comparably-priced luxury saloon though. The boot isn’t as big as, say, an S-Class or a 7 Series either and has quite a high lip, though there is the bonus of hatchback practicality.

Prices range from around £66,500 to about £123,000 – a span which covers a huge range of competitors. Despite this, there’s really nothing quite like the Panamera. Others may be more elegant, but there are few cars you’d choose over this contender from Stuttgart for demolishing big mileages quite so effortlessly.

It’s also hard to argue with the amount of kit the car gets as standard. There’s a full leather interior, Porsche Active Suspension Management (PASM), bi-xenon headlights, front and rear park assist, tyre pressure monitoring, 19-inch alloy wheels, automatic dimming rear view mirrors, Porsche communication management with touchscreen satellite navigation and audio controls, cruise control and a three-year warranty. That’s on top of adaptive air suspension and a Porsche Vehicle Tracking System (VTS).

The big step forward with this generation Panamera is undoubtedly efficiency. Fuel consumption is said to be lower by more than 10 per cent in the mainstream models.

None of these can, of course, hold a candle to the Panamera 4 E-Hybrid plug-in model. The claimed combined cycle fuel economy figure with this variant is a faintly ridiculous-looking 113mpg, which in real world scenario will translate to the mid-sixties.

When connected to an industrial outlet, the batteries can be charged within around two and a half hours via the integrated on-board charger and the standard Porsche Universal Charger (AC), and it can be charged in less than four hours when connected to a conventional household electrical outlet.

Porsche quotes an emissions figure of 56g/km, which is a significant improvement on the previous plug-in model’s 71g/km showing.

The V8 diesel version most will choose in the UK manages 42.2mpg on the combined cycle and 176g/km of CO2.

As for depreciation across the range, well that’s been a bit of a mixed bag to date.

The diesel model fares extremely well, while the thirstier petrol variants get hit hard.

That’s about what you’d expect, but the improved efficiency of many of the petrol-engined models should take an edge off depreciation henceforth.

Want the cleverest of all the big supersaloons? You’re looking at it right here in the revitalised shape of the Porsche Panamera.

Granted, not everyone loves a smart alec, but there’s something about the depth of engineering in this car that’s both enormously reassuring and hugely effective.

Great driving manners are a given. This is a Porsche after all. What’s not quite so predictable is the way the Panamera manages to worm its way into your affections after a while.

Porsche has made great strides in improving the Panamera’s efficiency, while the plug-in hybrid model remains an interesting, if pricey left-field option.

At the top of the line-up, you still get the crazy Turbo model, while the diesel will remain popular. And overall?

Well, we would never have thought it four years ago, but the Panamera might just have become the car to beat in its class.