What's it like?
Switch the ignition on and the 40e defaults to its Auto eDrive mode, which tries to use the electric motor as much as possible and engages the 2.0-litre petrol only when necessary. It does the usual electric thing of providing plenty of instant torque, while whisking you along in uncanny silence as you amble around town. You have to be judicious with the accelerator pedal, though, and keep your speed below 44mph, otherwise the engine will fire.
When it does, it cuts in smoothly and makes the 40e usefully quick, matching the 30d for outright acceleration and feeling livelier thanks to the engine’s eagerness to rev. It hasn’t got quite as much torque as the 30d, but the dual power sources help spread what it has over a wider range, and with more top-end power you don’t spend long in the danger zone when overtaking.
If you’ve got enough charge you can switch it to the Max eDrive mode, which runs on electric power up to 75mph. But if you do that speed you’ll get nowhere near the supposed 19-mile range - and, surprise surprise, 85.6mpg combined isn’t doable, either; on our trip to North Wales we couldn’t get much more than 25mpg, even when we were being sensible.
On stunning Welsh roads the 40e served up some typical X5 dynamic extremes. Our M Sport model on adaptive dampers offered great body control for a 2.3-ton car, happily resisting lateral g-forces and soaking up mid-corner bumps.
Unfortunately, the steering’s poor weighting and the front wheels' predilection to tramlining engenders distrust, which, combined with the grabby regenerative effect from the brakes, makes you disinclined to use all of the chassis' strengths.
It’s a tale of two halves inside, too. The cabin’s superbly made and hard to fault ergonomically, but at times the ride gets quite busy, while wind and road noise at speed diminish its effectiveness to cosset over long distances.
Should I buy one?
You need to do the sums to see if the 40e will give you any payback over a 30d but basically, if you’re not a company car user and spend most of the time on the motorway, chances are it’s not for you.
As a package, the X5 40e is great in many ways, but its weaknesses prevent it from being the automatic choice. The more practical Volvo XC90 T8 is certainly worth considering as well, and if you’re in the market for either, look out for our forthcoming group test when we'll pronounce definitively which is best.
BMW X5 xDrive40e M Sport
Location Wales; On sale now; Price £56,705; Engine 4 cyls, 1997cc, turbocharged petrol and electric motor; Power 309bhp at 5000-6000rpm; Torque 332lb ft at 1250-4800; Gearbox 8-spd automatic; Kerb weight 2305 kg; 0-62mph 6.8sec; Top speed 130mph; Economy 85.6mpg (combined); CO2/tax band 77g/km, 13%