The Lexus IS model range that went on sale earlier this year was the third to bear that name in fourteen years, but the first to be made available with a petrol-electric hybrid drivetrain.
While the IS 250 uses a 2.5-litre six-cylinder engine, the IS 300h has a four-cylinder unit of almost exactly the same capacity (there's only 6cc between the two) which combines with an electric motor to produce more power but less performance.
If that doesn't sound like much of a return for the hybrid's £3000 higher list price, take a look at the official green figures. The best ones, which apply to the 300h SE, are 65.7mpg and 99g/km, and while the Premier tested here can't match that because of its larger wheels, its 60.1mpg and 109g/km leave those of the IS 250 for dead.
In reality, 60.1mpg is a bit of a stretch, but on this test (which included a lot of motorway driving in foul weather conditions) the trip computer suggested that I averaged very nearly 50mpg. Even if that figure is optimistic by as much as 10%, it was a pretty good performance for a comfortable, almost luxurious saloon car.
It was achieved with the driving mode selector set to Eco. There are Normal and Sport modes too, and they make the hybrid system more keen to favour the engine over the electric motor than it is in Eco, but then you're sacrificing economy for performance, and there's very little about the car that makes performance seem like a good idea.
Lexus has been describing the different versions of the IS as "sports saloons" since the coughing-up-blood days of the 20th century, but none of the ones I have driven - including the undoubtedly quick and powerful IS F - seem to have been set up by anyone who shares my idea of what the word "sports" means.
It's the same with the IS 300h. Its ride and handling could reasonably be described as "stately", and once you start pushing harder it beings to feel flustered. As a sports saloon it's therefore quite disappointing.
It makes more sense to think of the IS 300h as a smallish luxury car. At moderate speeds it's very smooth, and I'm led to believe, on the basis of having transported four ladies in it one evening (oh yes) that it's very comfortable regardless of which part of it you're sitting in.
From the driver's point of view, it's very relaxing because all the major controls - in this case just the steering wheel and accelerator and brake pedals, since the car is available only with CVT automatic transmission - are beautifully weighted and very smooth. The fact that the motor becomes a generator and starts to slow the car down when you lift off the throttle means that it can take some time to get used to how little force is required on the brake pedal, but you get used to that quite quickly.
The IS 300h is also very quiet for most of the time. If you pull away from rest on electric power alone and continue to accelerate gently, it's almost impossible to tell when the engine has fired up without looking at the instrument panel to check. It's only when you start to use the throttle more vigorously that the unLexuslike four-cylinder engine note becomes apparent.
Perhaps the car's most unexpected trick is its ability to turn round in tight spaces. The turning circle is so small that the IS can be driven through 180 degrees in gaps for which nearly all superminis require a three-point turn. An odd talent for a car like this, but also a useful one.
You can experience nearly all of this in the £29,495 SE, but you have to pay an extra £9000 for the Premier tested here. Features unique to the Premier are 18" five-spoke alloy wheels (the cheaper Sport runs on 18s too but has twice as many spokes), satellite navigation displayed in a clear but not particularly adventurous manner on a 7" touchscreen, a very fine 15-speaker Mark Levinson sound system, leather upholstery, eight-way powered seats with heating and cooling functions, electric steering wheel adjustment, a rear-view camera and folding door mirrors.
The Premier also has the option, for a further £1540, of a Technology Pack, which is very much geared towards safety and includes a Pre-Crash system, adaptive cruise control, lane departure assist and automatic high beam selection for the headlights.