How a big SUV manages 85 miles per gallon

Firstly, the sort of people who buy high-end motors no longer go exclusively for sleek saloons, with many preferring versatile SUVs (sport utility vehicles) instead.

And, secondly, economy and the environment play a major part in decision-making when it comes to choosing a new vehicle, something that wasn’t quite so evident a generation or so ago.

That’s why cars such as this hybrid BMW X5 is on sale. Not only is it very much a luxury SUV with hi-tech features and sports-car performance, but it also economical. Very economical, in fact, thanks to the plug-in electric motor which makes it capable of more than 80mpg, a figure which would be commendable for a lightweight city car, never mind a three-ton beast like this.

OK, so hybrid vehicles aren’t for everyone. It takes a certain amount of dedication to plug in your vehicle to the mains for several hours to ‘fill’ the vehicle’s electric tank.

But when you get a car of such power and prestige which can return such exceptional economy, the few seconds it takes to hook up to the mains has to be worth it.

It is the first of several such vehicles which BMW is launching because, the company believes, the market is ready for BMW plug-in hybrids, and it seems they may be right given that more recharging points are opening all the time at motorway service stations, shopping centres and the like.

And, of course, hybrids have the benefit of being able to drive on petrol only if they electricity charge runs out and there is nowhere to recharge, doing away with so-called range anxiety which affects drivers of purely electric vehicles occasionally.

So, how exactly does the X5 measure up? Well, it’s BMW’s answer to the Range Rover, Audi Q7 and co and it was first launched in 1999 branded as a sports activity vehicle rather than sport utility vehicle.

This X5 - the X5 xDrive40e to give its proper mouthful of a title - is a luxury model which is both brutish and beautiful.

It combines a great 2.0 litre petrol engine with an electric motor in the boot and together they emit 313bhp (245bhp from the petrol engine and 113bhp from the electric motor) which means this vehicle has the sort of performance once restricted to hot-hatches.

You can drive it various modes which can put greater or lesser emphasis on the electric motor.

It returns a combined fuel consumption of up to 85.6mpg and the emissions are just 77g/km which means this vehicle is far cheaper to run than you would imagine.

The ride is firm but comfortable, thankfully lacking the roll that some big SUVs sometimes have. And it does offer a sports-car ‘whoosh’, thanks to a very efficient eight-speed automatic transmission.

The lithium-ion high-voltage battery pack can be topped up with mains electricity from any domestic power socket, or more quickly from the BMW iWallbox, as well as at public charging stations.

The high-voltage battery is housed underneath the luggage compartment floor, where it is well protected in the event of a crash. With a capacity of 500 to 1,720-litres, the luggage area is only compromised a little compared with other X5s. The standard charging cable can also be stored in a hinged compartment under the luggage area floor.

Short journeys in urban areas can easily be completed with no tailpipe emissions, while actual fuel consumption is cut when driving for distances of up to 15 miles in urban traffic. Driving in this way equates to an equivalent 94.2mpg, setting a new benchmark for efficiency in its segment.

On longer journeys, when both engine and motor need to be deployed, the powertrain keeps the fuel consumption and emissions figures far lower than in comparable models with similar power outputs.

Assuming the battery is fully charged, daily commutes of up to 37 miles can be completed at 43.5mpg.

When the fuel tank is filled to its 85-litre capacity and the battery pack is charged, it manages 25.7mpg.

You can configure the driving style to suit your needs via the grandly-titled Driving Experience Control switch and eDrive button.

When the vehicle is first started, the default AUTO eDrive setting is activated, with both engine and electric motor working together. The electric motor alone is used for setting off, while the petrol engine cuts in at around 44mph or when the driver accelerates briskly.

The driver can also switch to the all-electric drive mode setting MAX eDrive, where it is powered solely by the electric motor. This mode is designed for comfortable driving with zero emissions, and offers a range of 19 miles at a limited top speed of 75mph.

The third mode is the SAVE Battery setting, which allows the driver to conserve or build up the battery’s reserves for later. When driving on the motorway, for instance, the state of charge can be kept constant or even boosted in order to use the high-voltage battery’s power for all-electric driving in urban areas later in the journey. In this way, the stored electrical energy can be used when required.

As you would expect for a £50,000-plus car, it is well equipped. The cabin is the highlight for me with stunning satellite navigation and ‘infotainment’ system which is good as any on the road and better than the majority.

The cabin is comfortable - the seats are excellent and the controls superbly positioned - and the reversing cameras and radar system are simply stunning.

To whizz from 0 to 60mph in 6.8 seconds is fabulous and it cruises at motorway speeds with great stability.

Other features such as seat-heaters, leather upholstery, allloy wheels, illuminated door handles and huge information screen are excellent, too.

To say it is such a big and beefy car, it is modestly styled compared to some of its rivals.

* When hooked up to a domestic power socket the high-voltage battery can be fully recharged from flat in three hours and 50 minutes. With a BMW iWallbox it takes two hours, 45 minutes. Charging can be checked on a graphic displayed in the vehicle’s instrument cluster or on a smartphone using the BMW Remote app.

BMW X5 xDrive40e

PRICE: £56,705 on the road. X5 starts at £44,575

ENGINE: It has a 1,997cc four cylinder petrol engine and an electric motor motor generating 313bhp between them

PERFORMANCE: Top speed 130mph and 0 to 60mph in 6.8 seconds

COSTS: 85.6mpg on a combined route

EMISSIONS: 77g/km

INSURANCE: Group 42E

WARRANTY: Three years’ unlimited mileage