The Lexus RX is a long-time player in the large premium SUV market, having been around since 1998, and it's now reached its fifth model generation.

For fleets, the big news will be the arrival of a plug-in hybrid powertrain option, with corresponding very low official CO2 emissions and an 8% BIK company car tax rate. Two conventional hybrids are also available, but Lexus expects the PHEV - badged 450h+ - to account for 55% of UK sales. It features a 2.5-litre petrol engine and two electric motors - one on each axle - with a combined output of 309hp, and an 18.1kWh battery which allows an official electric-only range of 42 miles, securing that 8% rate.

Everyday driving is easily achievable with electric power alone. When the petrol engine is called for, although it isn't the most pleasant acoustically, the noise is fairly well suppressed even under heavy acceleration. Despite hot hatch-bothering official performance figures, the 450h+ never feels rushed or unrefined, just usefully rapid for a large SUV. It certainly never risks overwhelming the chassis - the RX's steering has a reassuring bit of heft to it, and its cornering manners are nicely controlled with no unwieldy wallowing. As for ride comfort, it's very well cushioned at A-road speeds in particular, and glides over expansion joints nicely, although over larger potholes the effects of the heavy SUV body and big alloy wheels are harder to mitigate.

Although Lexus is proud of its extensive package of driver assistance technology - and most of this is highly commendable - there are irritations. An audible warning every time the road's speed limit changes is annoying, and although it can be turned off this needs to be done again for every journey, and also requires delving into set-up menus. And the driver inattention warning system was as annoyingly overzealous as we've previously found in the Toyota BZ4X - sounding at one point during our test of the Lexus because we were looking at the door mirror in order to merge onto a dual carriageway.

Inside, a headline feature of the new RX is a new-generation infotainment system with a 14in touchscreen. This is an impressive set-up - the screen is large and easy to read, with clear graphics, and there's a good blend of touch and physical audio and ventilation controls. 

A head-up display is standard on Premium Plus Pack-spec cars and above, and as well as displaying the usual driving information is also cleverly linked with the steering wheel-mounted controls, giving the functions of buttons as the driver interacts with them. This seems a neat way of keeping the driver's eyes on the road, though we're not sure how useful it would be once a long-term driver learns what all the buttons do. 

Interior trim is to a high standard, with leather and high-quality plastics deployed, and the front seats are automatically heated or cooled based on the climate control temperature settings. However, when  taken with the infotainment set-up, while there's nothing really to fault here, we're not sure the interior as a whole offers quite the same wow factor as German rivals. 

Lexus says the new RX offers more legroom than its predecessor, and there is plenty of this in the back, as well as headroom, as you would expect. The boot is a decent size, but shallower than you might expect due to the need to accommodate the electric powertrain - although the 461 litres offered by our plug-in hybrid test car is no worse than the conventional hybrid alternatives in the RX range. On the subject of practicality, there's no longer a seven-seat option, the previous RX L variant being discontinued.