The RX 450h is a slightly baffling vehicle. Just what is the point of hybrid technology when the vehicle doesn’t return exceptional economy and isn’t that quick either?

Admittedly, emissions are fairly low at 120 g/km – making it cheap to run as a company car – but the similarly priced BMW X5 xDrive40e petrol-hybrid reduces CO2 emissions to a lowly 78 g/km.

Not only that, the BMW, like the Audi Q7 and the Volvo XC90 T8 hybrid, offers the option of seven seats. A feature missing from the Lexus for some reason.

So while I love the look of the Lexus – by far the prettiest of the bunch – it’s what drives the RX 450h that ultimately lets it down…

There is something rather lovely about rolling around town in the 450h – you sit in a silent cabin as the electric motors do all the work.

The only worry is the pedestrian who doesn’t hear the Lexus approaching and steps onto the road without looking.

And the cabin is a truly great place to sit. I can only imagine the seats were designed primarily for the US market because they are big and squidgy. Perfectly supportive but super sumptuous too.

The Lexus has grown on me but somehow it just lacks the dynamic nature of key hybrid rivals, like versions of the Porsche Cayenne and Volvo XC90. It’s an ‘almost car’ – almost rather good…

I’m loving the widescreen infotainment screen in our Lexus 450h test car this week. The sat nav screen is massive, the graphics are clear and somehow the screen doesn’t dazzle you at night either.

So why then is the control stalk that acts as a mouse so damn difficult to use?

BMW suffered abuse when their iDrive system first came on the market about 13 years ago. But the mushroomed-shape mouse in the Lexus requires the dexterity of a neurosurgeon.

It’s so sensitive that any road surface other than smooth will jog the cursor on to the next icon. And every time the mouse is clicked, it gives off an annoying sound.

It’s fiddly and awkward – possibly designed by a five-year-old and lets down the rest of the interior big time…

As already noted, fuel economy is not a strong point for the RX 450h. To the man in the street, this might seem a little odd, given that this is an expensive petrol-hybrid car.

To the long in the tooth motoring writer, it’s a little strange too. Today I drove the Lexus around Cirencester and the slightest blip with the right foot brought the petrol engine in to play.

I know this because the RX has a huge infotainment screen that dominates the top of the dashboard in w-i-d-e-s-c-r-e-e-n. And I mean wide.

In the ‘CAR’ setting, you can monitor a diagram of the Lexus showing where the energy is coming from to drive the wheels.

Now, I tried damn hard to keep it in electric motor only but it’s almost impossible. A decent diesel SUV would do better, if I’m totally honest.

So, just what is the point of the RX 450h. Great technology but rather useless in the real world…

The wicked styling may not be enough – the Lexus RX just doesn’t drive well enough to tempt people away from the Porsche Cayenne and BMW X5.

The problem is the CVT automatic gearbox. It just doesn’t put the power available to good use. The 450h feels like it’s straining, the steering isn’t quite on the money and there’s body roll on cornering.

This latest RX is far better than the previous model but it lacks the driving dynamics to make it a great SUV – or live up to those incredibly stylish looks.

And why is the fuel economy so poor for a hybrid? Around town you might get up to 45mpg if you drive carefully and the electric motors do the work. But in the real world, I can barely hit 30mpg.

That means the RX 450h with all its technology is trounced by your average diesel SUV – many of which are faster off the mark too….

Let’s not worry about the technology. Just stand back and marvel at the styling of the latest RX 450h.

I’m genuinely surprised – it knocks the style-less X5 for six (not difficult) and gives the Range Rover Sport a kicking too. Is there a prettier SUV out there? I think possibly not.

The angular lines are aided by some gunmetal paintwork. It costs an additional £645 but the result is a fantastic statement of futuristic design. This is a spaceship on four wheels. I’ve been marveling at it all day.

On Friday I will try the RX on the road and see if it lives up to all that promise…