Sector: Executive Price: £43,495–£50,995 Fuel: 45.6–64.2mpg CO2: 104–145g/km

The Lexus GS is a car of considerable prestige, which, as it turns out, is a quality mostly afforded by virtue of mystique. In 2015, while BMW, Audi, Mercedes and Jaguar were between them selling 73,000 executive saloons in the UK, Lexus sold 450.

The huge sales of those executive titans is easy to fathom: the 5 Series, E-Class, A6 and XF are each well established, each brilliant in their own way, and each available with a frugal diesel engine or two.

But the GS is, by now, well established too – a safe bet if ever there was one. Now in its fourth iteration since 1991, to buy a GS Is also to buy into a company whose reputation for quality and dealer service is second-to-none.

The problem is, despite an update for 2016 the latest GS is neither brilliant, nor in possession of a diesel or two. In a segment replete with four- and six-cylinder diesel engines, Lexus gives UK buyers a choice of two petrol-electric hybrids, named 300h and 450h.

In defence of this Lexus would point to the numbers. A typical 60,000-mile business user will save hundreds per year in BIK when choosing a GS 300h base model instead of a German diesel executive saloon, owing to a 15% rating. Fuel economy is excellent too: 65.7mpg and 104g/km, when on 17-inch wheels.

So that’s the diesel issue overcome. And then there’s the new base model, which is so squarely aimed at business executive that Lexus has called it Executive Edition. It adds leather upholstery, Lexus’s fancy new widescreen navigation system and a whole suite of safety technology including automatic low speed braking, all for a nominal fee over the SE model it replaces.

So if there’s one thing the GS does well, it’s the bottom line game. It also does the actual bottom game very well too – most of the time. The way the GS shuts out wind and road noise is exemplary, the chairs are soft and comfy, the steering light, and when it’s floating around on electric power, not being worked hard, it’s really as quiet as can be.

The problem comes when you need a bit more oomph, or on a less than perfect road. Quiet becomes din as the CVT gearbox whines its way to the most economical ratio. And suspension tightened to deal with the GS’s considerable heft thumps potholes like a whack-a-mole. That heft is the same reason the GS uses far more fuel than you’d expect, given the stats.

And then there’s the interior generally. The GS feels ‘techy’ inside, which is its own sort of appeal, but it’s not luxurious. It’s not very spacious either, lacking rear leg space and boot capacity – about 90 litres short of a Jaguar XF’s, which is quite a few golf clubs or smoking jackets.