The Austrian ski resort of Hochgurgl is 2150 metres above sea level - roughly equivalent to two Mount Snowdons or nearly three Burj Khalifas. When we visit in early December, temperatures on the exposed, wind-chilled summit of the road that winds up from here and across the Italian border – usually closed for winter – have reached a balmy peak of -15dec C by mid-morning. 

The wind is unforgivingly biting and the road completely covered in thick, heavily compacted snow. There are darker patches that you might mistake for the safe, grippy refuge of uncovered Tarmac, but more fool he who seeks traction on this blackest of black ice. 

We’re here partly because “driving on this road is cool”, admits Mercedes-Benz CLA project leader Oliver Zolke as he casually lets the back step out midway through a particularly icy hairpin, but primarily because it’s the best environment for showing off three defining characteristics of the newly electric saloon: "The ability of the recuperation, the traction and uphill acceleration, and the softness of the suspension”.

From the passenger seat, the third-generation CLA feels to all intents and purposes finished. Camouflage cloaks the finer design details outside and the obligatory black bedsheet shields the dashboard from view, but Zolke says it’s “99% there” ahead of an unveiling in March and a launch around summer, with just “some homework” to do on the software and user interface.

Even with much still left to the imagination, it’s clear just how closely this car will be to the pleasingly proportioned concept from last year - right down to the full-width digital display we can see peeking through the gaps in the sheeting. For better or worse. 

Our test car is the range-topping four-wheel-drive model (Mercedes-Benz CLA 4Matic with EQ Technology, to give its full name), equipped with a 268bhp motor on the rear axle and another with 107bhp at the front. Mercedes has yet to confirm a combined output, but bank on around 375bhp, which should give it a slight accelerative edge over the Tesla Model 3 Long Range AWD and the dual-motor Hyundai Ioniq 6. 

This is one of two electric powertrains being introduced for the next-generation CLA, which is described as the first car of the ‘EV 2.0’ era for Mercedes, so dramatically different is it from the current EQE and EQS. The other forgoes the front motor for a smaller list price (expect low-£40,000s for the version with the smaller 58kWh LFP battery) and a higher maximum range of somewhere around 440 miles from the 85kWh NMC pack. 

There will also be a combustion version, pairing a 1.5-litre petrol four-cylinder engine with a small electric motor in the gearbox for up to 188bhp and claimed "diesel levels of efficiency". It's due around six months after the EV, towards the end of 2025. 

The range-topping EV certainly feels brisk enough, even on this glassy terrain, when Zolke floors it from a standstill, the lack of scrabbling and sliding off the line testament to the advanced stage of development this all-new powertrain is at - although potentially also the legally mandated chunky winter tyres that our mule is wearing… 

A long straight section of the otherwise ceaselessly meandering Timmelsjoch pass provides the opportunity to briefly exploit the CLA’s full reserves, and we surge quickly and confidently to north of 60mph, which wouldn’t feel especially rapid but for the unnerving sense of detachment that comes from having such limited reference points. With the roadside largely indistinguishable from the blacktop and no fixed landmarks flicking past the window, we might as well be doing 150mph, or 20mph. 

Either way, the CLA is unflustered. I did the same thing in the same place a few minutes previously in a Mercedes-AMG C63 and, even allowing for the assistance of 4WD and winter tyres, found myself making constant small corrections to my line in order to keep the nose pointing the right way. Zolke’s arms remain rigid by comparison: “There’s not much work to do from the driver’s seat,” he remarks, the car tracking straight and true with no perceptible directional input from either man or machine. 

Zolke maintains his relaxed demeanour as a tight right-hander approaches, carrying our cruising speed well beyond the point at which I would have started bleeding off the pace. As the apex comes into focus, he lifts off the accelerator but leaves the brake pedal alone to demonstrate the efficacy of the regenerative deceleration, which can send power back to the battery at speeds of up to 200kW. 

"There's no need to do any mechanical braking" in D mode, Zolke explains. It would be more efficient in terms of energy usage, but "more smooth is the recuperation, as you don't feel it". To demonstrate the contrast, he gives the left pedal a good stab and our conversation is interrupted by the noisy and juddering intervention of the ABS, which despite its best efforts is unable to bring the car’s speed down any quicker than the motors.

The 4Matic model has an advantage here, because the second motor on the front axle boosts the maximum regeneration rate, but the rear-driven CLA will also be able to stop with no physical brake input. "And that's more or less a side effect of efficiency. We didn't do it for these conditions; we did it to get maximum energy back from the car," says Zolke.

Judging the suppleness of the chassis is trickier, given the tyres don’t really come into direct contact with the road itself during our time in the car, but the fact that I’m able to chat with Zolke while simultaneously writing in my notebook on one of Europe’s most challenging roads is probably an indication of its composure. Unlike the bigger electric Mercs, the CLA will be exclusively coil-sprung, but with optional adaptive dampers for greater control over the suspension characteristics - as with the BMW i4 and Tesla Model 3.

Beyond its dynamic credentials and straight-line performance, the CLA is aiming to steal sales from its rivals with a claimed cruising efficiency of 5.18mpkWh - giving it long-distance abilities that it has proven by breaking the record for the longest distance travelled by an EV in 24 hours: 2410 miles around Italy’s Nardò high speed ring. Minimising power wastage at a cruise is crucial to attaining that figure, but being able to charge at up to 320kW dramatically reduces time spent idle.

Zolke acknowledges that it's a big ask to marry segment-leading efficiency (Mercedes loftily refers to the CLA as “the one-litre car of the efficiency age”) with highly competent dynamics and engagement, but "the biggest challenge of the project" was instilling the new saloon with all those attributes while also keeping it tightly proportioned and low to the ground.

He explained that Mercedes' focus for EVs has so far been focused on 'higher' – both taller and more premium-focused – model lines, because of the cost and bulk of EV batteries, but as both of them come down, lower ride heights become possible. Nonetheless, Zolke said, there was a paradox to address: "The challenge was the height of the car, because we need space for the battery underneath but to keep the height comparable to the predecessor for styling, you don't want to have it too high – also for aerodynamics.”

Even with the car still heavily camouflaged, it's clear that the CLA is a close proportional match to its predecessor, and the seating position feels roughly as low-slung as it would in a petrol saloon. Comparing the two with each other – and with their respective rivals – post-launch will give a clearer picture, but the early signs point to the new CLA being a remarkably uncompromised all-rounder.