In so many ways, I find this all a bit sad. I find it somehow sad that PSA group has decided that Citroen can no longer bear the burden of competing in the premium sphere and so, logically, the existing, ritzy DS models are being spun off into an entirely separate, standalone, very much premium DS brand.

It makes utterly logical sense. The world has gone premium brand mad and so the mathematics of the situation are inexorable. Around 10 per cent of global car sales are now premium badge products, and they contribute as much as 50 per cent of incoming profits.

PSA would be mad not to follow this particular rabbit down the hole. Its experience in China, where the DS badge has been uncoupled from Citroen since its introduction, is more than encouraging – in fact it's imperative. Split DS away, demerge it from memories of cashback Saxos and discounted C4s and, so say all the experts, the more solid will be the ground upon which your premium badge cash cow will stand.

So why am I sad? Because I remember when Citroen was both premium and affordable at the same time. All during our attendance at the launch of the DS5, now shorn of any Citroen badging or connection, the refrain ran the same confused line. Sixty years of heritage, 60 years since the launch of that inimitable original DS saloon, but this is a new brand, a premium brand.

And that's where the sadness comes in. Sadness that André Citroen's eponymous brand, the brand that in the space of three decades gave us the Traction Avant, the 2CV and that first DS, is no longer thought highly enough of such that it can't compete with Audi and BMW. To put that in context, when the original DS was launched, BMW was making its money from bubble cars and Audi was a forgotten brand of the 1930s.

Pining for past?

Is this just a middle-aged man, pining for a half-remembered past? I don’t think so. It’s a sense that the world has reached a poorer point when such amazing history has to be essentially abandoned in order to compete. And competing is going to be about so much more than just a badge and a brand.

Take the DS5. It is, of course, a car we already know as an upmarket Citroen, and it's meant to be an alternative to the German mid-size three- box-saloon hegemony. It's always been a pretty car, with a particularly gorgeous interior, but it's also always suffered from being too small inside, too harsh in its ride quality and being neither (a) German nor (b) a saloon.

Now that it's a DS, has anything changed? Well, some has. It gets a new grille, which is somewhat more Germanic- looking, and a mildly made- over interior. There are new engines too, and those are perhaps the points most deserving of praise. Peugeot and Citroen have traditionally been at the cutting edge of diesel engine design and development, and these new "BlueHDI" engines are right up with the best. The 2.0-litre 150hp version has a genuinely exceptional mix of refinement, acceleration and economy. 110g/km for the manual gearbox version pegs this powerful 2.0-litre engine to the same tax band as the old 115hp 1.6. That's impressive.

Fuel consumption

Slightly less so was the 180hp version, which is quicker and hardly any worse when it comes to fuel consumption and and

emissions

, but which sounded much less refined, more audibly grumpy, than the 150hp. The lesser engine, here, is the greater.

The cabin is a thing of utter beauty too. DS, as a brand, is making much fuss over its sense of craftsmanship and it's following in the footsteps of other great French luxury brands: Cartier. Chanel. DS. With this I have no trouble: the fit and finish are excellent, the quality of such things as the leather and metal used inside are terrific and the seats are wonderfully comfortable. It's not very practical though. Space in the back is quite poor and up front, things like decent cup holders are noticeable by their absence.

And then we come to the dynamic performance. When launched in 2012, the DS5 was, rightly, panned for being unacceptably rough over bumps and lumps, with no appreciable trade-off in driver entertainment. Improvements were made along the way, and improvements have been made again now for its relaunch, but the sad fact remains that here is a luxurious French car that cannot provide a relaxed ride comfort.

It's definitely better – the spring rates are easier, the sense of jitter and fidget reduced, but it remains noisy over bumps, with each creak and groan of the suspension transmitted through, and it's not as finely damped and controlled as a BMW 3 Series or Jaguar XE. As motorway transport, it's lovely – smooth, soothing and refined – but on rural or urban roads with poor surfaces, it's still behind the curve.

Holding pattern

PSA and DS kinda know this. The DS5 and, when they come on stream, the updated DS3 and DS4 are a holding pattern. We won’t see proper, designed- for-the-brand DS models until 2018 when it will kick off a new six-car range that will include a large SUV and a new big saloon, which is promised to include a radical new suspension set-up.

DS execs say that this is a long-term project, that they’re reckoning on 15 years and two full model cycles before the brand is on a parity with Audi. Quite whether the quarterly-result-obsessed investment community will give it that much breathing space remains to be seen.

And when all is said and done, 15 years is a long, long time to take when you think that Citroen took just a few seconds to turn the motoring world on its head, when it unveiled the first DS 60 years ago. Lowdown: DS5 2.0 BlueHDI 150hp

Price: From €36,000

Power: 150bhp

Torque: 370Nm

0-100kmh: 9.8sec

Top speed: 210kmh

Claimed economy: 4.0l/100km. (70mpg)

CO2 emissions: 110g/km

Motor tax: €190

Lowdown: DS5 2.0 BlueHDI 150hp