Big Citroens don't come along very often, so the launch of the C5 X is a significant occasion.

Taking its DNA cues from the Experience concept car first shown six years ago, the C5 X is an important statement car and one that necessitated a new market approach. Sitting at the top of the Citroen range, it is, according to UK managing director Eurig Druce, a car that the company could not have launched three years ago.

“We lacked credibility to launch this type of product. Our residuals were poor, and we had a history of overtrading in the rental market,” he said.

Druce has since cleaned up the channel mix and says his sales plans assume no short-term business for the C5 X, which will be build-to-order only.

Volumes are fluid, but could potentially reach 7,000 a year, with at least half going into the true fleet sector. “We have to be led by customer demand, though – we won’t force the market,” said Druce.

So why is Citroen launching a halo car into the wilting D-segment, a category that last year accounted for just 0.9% of the UK market (and headed by the Skoda Superb with a little over 4,200 sales)?

The simple answer is: it isn’t. The C5 X has been designed as a segment-straddling car, one that is equally at ease challenging family hatchbacks as it is estate cars and – crucially – C-segment SUVs.

This means a voluminous 545-litre boot (surpassed only by the Superb), generous space for passengers, SUV-diameter 19-inch wheels, a high belt line and muscular rear.

It’s a family car that has been put on a diet of creatin, egg whites and weight training, resulting in a pumped-up model that offers a higher driving position but still encased within an aerodynamic silhouette.

Citroen believes people are getting tired of the “boxy design” of an SUV. It predicts 21% of customers will come from the traditional D-segment, 25% from D-segment estates and 20% from C-segment SUVs, with the rest shared between C-segment hatches, estates and MPVs.

There’s no disputing the C5 X stands out from the crowd, achieving Citroen’s desire for a “surprising and disruptive” design. It’s a throwback to the distinctive shapes of forebearers such as the original DS and CX.

That’s one Citroen brand value box ticked; what about comfort?

Let’s start with the seats, an unheralded element of a car, but the one with which drivers are most intimate. They consist of several layers of textured memory foam with a high density top sheet and elastic cover for ultimate wellbeing.

The degree of support, cushioning and comfort is incredible: wave goodbye to backaches, I defy anyone to feel the slightest twinge after even the longest, most arduous journeys.

On the road, the C5 X almost floats along – Citroen was aiming for a ‘flying carpet effect’ and it’s very nearly pulled it off. In comfort mode, the active suspension laughs in the face of road imperfections with sensors reading the road surface to trigger individually controlled hydraulic dampers that also limit swaying and body roll.

In our view, for the money, nothing gets close to these levels of comfort.

Select sport mode and the steering response tightens while the suspension stiffens, but it would be disingenuous to describe the C5 X as a sporty drive. It corners well enough, but everything feels remote and detached. Despite Citroen’s best attempts, it hasn’t found the magic formula to mix ultimate comfort and sport in one package, but it is a more convincing drive than most taller SUVs.

Noise insulation is another big tick, though. The acoustics are excellent, with very little road and wind noise intruding into the cabin. This is particularly noticeable while on electric mode in the PHEV.

The C5 X will be available with two PureTech petrol engines – 1.2-litre 130hp (136g/km) and 1.6-litre 180hp (147g/km) – plus the plug-in hybrid (225hp) which has 34 miles of electric-only range and charges to full in 1hr40mins on a 7.4kW charger.

Pricing starts at £26,490 for the 1.2-litre Shine, with the PHEV from £35,190.

The PHEV is the obvious fleet choice with its 30g/km attracting BIK at 12% (from April 2022) - around £70 per month for a 20% taxpayer. This compares to £140 per month for the entry 1.2 (32% BIK).

All three engines come with automatic eight-speed gearbox and a choice of three trims: Sense Plus (1.2 and PHEV only), Shine and Shine Plus.

A range of safety tech is standard, including lane assist, blind spot monitoring and parking sensors/rear camera. Shine and Shine Plus get a 21-inch head-up display and 12-inch infotainment screen (10-inch on entry level Sense Plus).

Available to order now, deliveries of the C5 X will begin in late spring.

Specification shown for Citroen C5 X PHEV Shine.