Lexus RX 450h

The hybrid Lexus gave a good account of itself in its last road test appearance, but here it’s expensive and comfortably outclassed. Electric motors help in mild conditions, but torque steer and a clumsy CVT gearbox mean the RX 450h is only really suitable for dry tarmac.

Our final four-wheel-drive contender is definitely the odd one out. While most manufacturers agree that diesel power works best for off-roaders, Lexus has taken a different path, by using a pioneering petrol-electric hybrid in its RX 450h.

The benefits are clear, though: despite the fact it produces a healthy 246bhp, emissions of 145g/km mean it’s the cleanest car here.

It’s also the cleanest four-wheel-drive SUV on sale – costing just £135 a year to tax. Plus, the Lexus can run on electric power alone at speeds of up to 25mph, which makes for extremely quiet and refined driving in town.

The company’s hi-tech approach also extends to the four-wheel-drive system. It’s called E-Four Permanent All-Wheel Drive, and comprises a 3.5-litre V6 petrol engine that powers the front wheels, plus three electric motors – two on the front axle and another 50kW one that turns the rear wheels. Yet all this assistance only kicks in when extra acceleration or traction are required. Sensors constantly monitor how much grip each tyre has, but as in the BMW, the system is reactive, so the Lexus only becomes a true four-wheel-drive vehicle once slip has been detected.

You can really feel the difference in the way the RX drives. If you’re too demanding with the throttle, for instance, it’ll start to torque steer while you wait for drive to be sent to all four wheels – a strange feeling in a 4x4.

The driver can choose from four different settings for the drivetrain: EV, Eco, Snow and Sport. Snow mode constantly feeds power to every wheel for maximum grip in icy weather, while the on-board energy monitor shows you how the system is working in real time.

There are limits to what the part-time 4WD can cope with, though. Lexus makes no secret of the fact that the RX 450h was designed with smooth tarmac rather than muddy country lanes in mind. With no extra body protection and limited ground clearance, it’ll struggle to negotiate anything more than a wet field.

Still, there’s nothing wrong with how it performs on the road. It matched the BMW’s 7.9-second 0-60mph time, which is even more impressive when you consider that the 2,205kg Lexus is 157kg heavier than the Ford Ranger due to its large battery packs.

Direct steering and a decent amount of grip mean the RX corners neatly enough, while the F Sport model we tested comes with stiffer suspension than the standard car. Opt for Premier trim instead, and you get supple air-suspension, adaptive dampers and a self-levelling rear for when you’ve lots of luggage.

The hybrid drivetrain’s final trick was its surprising efficiency – thanks to driving the front wheels most of the time. In our hands, the Lexus returned 27mpg, which is more than the Audi or Ford. But like all hybrids, the RX is expensive compared to conventional rivals, and if you need to head off the beaten track, there are much better cars for the job.