We have driven the middle-sitting version of Jaguar’s brand new flagship four-door, the XJ 5.0-litre V8. It’ll be the biggest-selling XJ in the range globally, and is expected to account for 60 per cent of all XJs built on Jaguar’s Castle Bromwich production line.

It’s not difficult to see why Jaguar expects sales to pan out that way. A diesel XJ costs almost Rs 9lakh less than the petrol V8, and it also offers more torque, is barely half a second slower to 0-100kph. So should you automatically discount this latest version of new S-class fighter? Not if you’re smart.

So what’s it like? It’s quiet. That isn’t to imply that other versions of this car are noisy – far from it – but it’s amazing how hushed Jaguar has been able to make this car without high-pressure common-rail diesel injection or a whining supercharger to deal with.

Thumb the ‘Engine Start’ button and there’s a distant whirr of a starter motor, followed by a pleasant and momentarily loud exhaust woofle. Shortly afterwards, the engine settles into an idle that’s barely audible through the car’s thickly insulated door seals or via the padded front bulkhead.

On the move, the relatively low compression ratio of that big 5.0-litre V8 means that, while you’re very faintly aware of engine movements in a V6 diesel XJ, you feel no engine vibrations at all in this car. Plenty of low-end torque provides generous, old-fashioned ‘waftability’ around town, and in standard ‘D’ mode the car’s automatic gearbox is perfectly optimised for relaxed, refined urban cruising.

Jaguar’s development engineers claim that, although it’s a regrettable loss, the ‘dialling out’ of the old XJ’s cosseting secondary ride was worthwhile, given what this car gains as part of the compromise. And in this tester’s opinion, they’re right.

It’s true that, in Portfolio specification and riding on 20in alloys, this car feels more directly connected to the road surface than passengers used to travelling in some limousines will expect. At low speeds the new XJ doesn’t glide over ridges and cobblestones quite as imperviously as the old one did.

The trade-off for those lucky enough to be sitting behind the wheel of this new XJ is that it doesn’t float and heave its way along a swiftly tackled country road like the old one might have, either. It’s got body control that’s perfectly judged for barreling along at eight-tenths, quick, accurate and really communicative steering, an automatic gearbox that’s instantly responsive to the wheel-mounted paddles, and bountiful, tuneful performance.

Two facts in particular should whet your whistle when it comes to driving this car. The first is that, like all new XJs, it has the same steering rack as Jaguar’s excellent 503bhp XFR super-saloon. And the second? That this is the lightest new XJ you can buy. With its aluminium underbody, this car is actually 20kg lighter (in short-wheelbase form) than an identically engined XF. And it drives with every bit as much precision and sporting composure as the smaller saloon, as well as with even greater refinement.

If you don’t expect to do stellar mileages and you simply want the most hushed and limo-like XJ you can get, then this is the one you should put your money on. This car also happens to be just as grippy, composed and rewarding to drive quickly as the XJ Supersport, albeit slightly less grunty.

If you’re buying an XJ and you plan on keeping it for a long time, this model makes great sense for an entirely different reason: longevity. This car also represents keen value for money relative to its immediate competitors. This Portfolio version is cheaper than a Mercedes S500L and Jaguar’s long-wheelbase Premium Luxury spec undercuts even the BMW’s 750Li.