Lexus GS 300hBMW 5 Series. Audi A6. Mercedes-Benz E-Class. Since the demise of mainstream execs like the Vauxhall Omega, the demise of the Volvo S80’s competitiveness, the demise of Saab, executive car drivers have for years had but three choices.

Recently, Jaguar has successfully made it four, with savvy XF variants such as the 2.2D and R Sport. Lexus has long tried to do the same, with little success. But with the latest GS 300h, it reckons it’s finally in with a fighting chance.

Conventional logic says it’s misguided. The executive sector loves its 2.0-litre diesels, and variations of the four-pot oil-burner dominate the sales of all three big players.

And Lexus doesn’t offer a four-pot diesel. Indeed, doesn’t offer a diesel at all.

It does sell an expensive V6 hybrid, but despite appearances, that’s not where the volume in this sector is. Price is still key and the Lexus was just too expensive. And the old, slightly foolish, V6 petrol-engined GS 250 was just too staggeringly uncompetitive in terms of economy and emissions to be remotely within a shot of consideration.

At last, though, it’s brought something to market that exec buyers could actually consider: the GS 300h. Combining 2.5-litre petrol engine with hybrid drive, it costs from £31,495 and has emissions from 109g/km. Instant wins, both. On paper, these two fundamentals, combined with the Lexus premium image, mean it suddenly has everything necessary to jump into the ring alongside the Audi, BMW and Merc.

That’s why I’ve got one out for a week’s testing. I’m familiar with the German alternatives, and all are worthy of merit in their own right (indeed, the BMW leads the class, and is a fantastically well configured car). How does a petrol hybrid compare to these turbodiesels, then? Indeed, how does a Lexus fare alongside them?

First drive – Lexus GS 300h…

The first five minutes suggests, well, really rather ably, actually. The GS is a big car, that has presence, certainly an equal to the others. I’ve actually got the F Sport on test (£41k instead of £31k, but the drivetrain’s the same for all…), which looks even more flash and fantastic, but the basic shape certainly has lots of near-five-metre-long presence.

Inside, it’s lovely. Lexus may just build a better quality interior than Audi right now. Certainly it feels better crafted, with fantastic attention to detail and some utterly indulgent grades of leather and piano black plastic in evidence.

The seats feel ‘rich’ to sit on, the dashboard is an array of commanding high-tech sophistication and it basically feels not far shy of a luxury LS inside.

Lexus GS 300h 5Pedestrian-surprising treats in the start-up, as the engine doesn’t fire up until you’re actually rolling, in typical hybrid fashion. When it does, and when it’s cold, the gruff fast idle means there’s no missing it’s there, but it’s still quieter than the often surprisingly vocal four-cylinder German competition, so really shouldn’t be grumbled about.

Besides, the silence when it’s off – which it will be once you’re cruising – really is sector stand-out. This is an extremely refined car indeed: Lexus has eliminated wind noise, minimised road noise and even gone a long way to eradicating bump-thump bangs. Here, it genuinely does have the rolling plushness of a luxury car, and you’ll never know it’s a mere 178hp four-pot beneath the bonnet if you take it as easily as I did on the in-town few-mile first drive.

I’ve got surprisingly high hopes for this car. It’s one that, at last, has the potential to meet the needs of its key market perfectly, so I’m hoping the reality bears out. Come back next week for more – oh, and for an accurate economy roundout, too. I’m certainly planning to cover the miles necessary for some accurate real-world findings…