There has been a real shift-change in the luxury saloon market, as far as how these models are powered. The latest Mercedes S-Class is available as a plug-in hybrid, and if that's not enough there is its full-electric sister car, the EQS. 

BMW's response is the i7, which was launched in all-electric xDrive60 form (that we have here) earlier this year. However, BMW will also be offering two plug-in hybrid versions of the i7. 

Whether you choose PHEV or EV power, all models have four-wheel drive. Top M Performance versions are models in their own right - elsewhere there's the choice of Excellence and M Sport (like our car). Confusingly, on top of this, M Sport Pro and Ultimate option packages can be added - our car had both.    

The i7 sits on the same CLAR architecture as the X5, but this is its longest application yet, and equals a comfortable and spacious driving position, but almost palatial levels of space in the back and a 500-litre boot. 

Considering the £140,000+ (including option packs) price of our test car, the i7's interior feels worthy of the price in our opinion, from the soft quilted leather on the seats, to the carbon and cut-glass trim on the dash and the metal speaker guard on the doors. 

Our test car also benefited from £28,000 of 'Ultimate Pack' which includes the incredible BMW Theatre Screen and Bowers & Wilkins surround sound system. With a 31.3in screen that folds down from the roof, combined with iPad-like controllers in the rear doors and the sounds, this BMW was transformed into a mobile cinema - it was very impressive. 

Outside, the looks will divide. The i7 is a tall, chunky, and distinctive design, but was improved with our M Sport spec's dechrome and 21in M Star-spoke alloy wheels. Like other recent BMW designs, we think it will look better the more there are on UK roads.

The BMW i7 xDrive60 is powered by one electric motor at the front axle, with the drive units delivering a combined output of 544hp and overall torque of 745Nm. Despite weighing more than 2,600kg, this i7 can sprint to 60mph in just 4.5 seconds and on to a highly illegal licence-losing but equally impressive 149mph top speed.

The i7 also benefits from a 101.7kWh high-voltage battery, which is positioned in the car's underbody, meaning that BMW is quoting a range of up to 387 miles - although we saw around 300 miles to charge. 

When it comes to charging, the i7's combined unit allows single- and three-phase AC charging up to 11kW, which can be optionally increased to 22kW (three-phase AC). As such, the battery can be fully recharged from empty to full in a rather slow 10.5 hours. DC charging up to 195kW also means the i7 can be charged from 20 to 80 per cent in a period of 30 minutes.