The new Lexus hybrid shows how a powerful car does not have to be a guilt trip, says motoring editor Andy Russell.

Let's talk green cars. if I claimed a 3.5-litre petrol V6 with total power of 341 brake horsepower, capable of 0-62mph in under six seconds and a top speed limited to 155mph was such a car you might think I was bonkers.

But there is such a car – the luxurious Lexus GS450h – and it's a hybrid, capable of running on battery power alone, eking more than 40 miles out of a gallon and with CO2 emissions on a par with a 1.6-litre petrol family hatchback.

It may not be what you think of as eco-friendly but what it does do is to prove that green cars don't have to be worthy but dull.

The fourth-generation GS looks far more dynamic than its predecessor, especially in F Sport guise with its more muscular bumpers, rear spoiler and dark-finish 19in alloy wheels, and that makes it more appealing against the likes of the Audi A6, BMW 5 Series and Mercedes-Benz E-Class.

So, in such illustious company, why should you go for the Lexus. For a start, it's going be more exclusive with fewer sold and, secondly, the range-topping hybrid version is mean and green.

The entry GS250 gets a 207bhp 2.5-litre V6 petrol engine but the real powerhouse green machine is the hybrid 450h which mates a 288bhp 3.5-litre V6 petrol with a 197bhp electric motor to give a total output of 341bhp with eco, normal, sport and, on F Sport versions, sport plus driving modes which not only varies the engine response but tweaks the car's suspension to improve stability and make it feel sportier to drive.

You can run on battery power alone for a couple of miles at city speeds with a light foot but I found that in real-world commuting, with the battery recharging when the car is slowing and braking as well as from the engine, you are unlikely to exhaust it with the power switching seamlessly between electric and petrol.

Put your foot down hard and both power systems combine to make this executive saloon surprisingly fleet of foot but it remains remarkably refined and quiet.

The new 450h cuts fuel consumption by more than 20pc and I saw 38mpg overall with a best of 43mpg – short of the official combined figure but not bad given the size of car and its performance.

And the more I drove it the more adept I became at making the most of the hybrid system to run on battery power and electric motor alone as much as possible, even maintaining 35mph.

With its hybrid drive system and hi-tech running gear if you like your gizmos you'll love the Lexus which in F Sport has a dynamic handling system. It's all very clever but it has made the latest GS much more rewarding to drive without losing that luxurious Lexus ride quality and so overcoming a criticism of earlier GS models.

It's not in the BMW 5 Series league but with the F Sport's retuned suspension and adaptive variable system it's certainly entertaining for such a big car, keeping the GS in check even when being pushed hard through corners and inspiring confidence. It hasn't been at the expense of ride comfort though and, despite giving taut body control, the suspension soaks up bumps and lumps in its stride.

The upmarket, elegant cabin oozes quality and tactile materials making it a soothing and most pleasant place to be. For all the complicated technology, the driving environment is straightforward with logical controls and switches although the computer-style mouse controller between the front seats for many of the infotainment system functions takes a little practice. But I loved the way the 'eco meter' magically changed to a rev counter in sport and sport plus modes.

The cabin isn't as roomy as some rivals and legroom in the back is only adequate for six-footers but the real bugbear is the size of the boot given the need to store a big drive battery somewhere. It sounds large at 465 litres but is much shorter than the conventional GS250.

As we have come to expect of Lexus, equipment levels are generous and the GS450h comes with just about everything you could ever want... apart from metallic paint which is an option!

The Lexus GS450h is not cheap, even against German rivals, with the flagship models topping �50,000 but they want for nothing, are beautifully built and engineered and, despite the power and performance, you are driving something that is seen as being relatively kind to the environment.

So if you want a big, luxurious saloon this handsome hybrid means owning one won't be a guilt trip.