Mercedes-Benz S400d 4Matic L AMG Line 2021 UK first drive

The S-Class’s old ‘sleeping seat’ functionality, which allowed the nearside front seat to slide and fold forwards and the rear seat behind it to extend almost flat like a bed, isn’t available on the new version yet. Like the rear-seat flatscreen displays, it’ll come later – and probably first on the Maybach version. It’ll be a bit of a theme, that.

Without that extra steered axle we covered earlier, the S-Class’s sheer size can make it tricky to drive in tight spaces; around multi-storey car parks, too, of the sort that posh airport transfer specialists do frequently have to negotiate, let’s not forget. The car will overhang a typical UK parking bay at both the front and rear. Visibility is better than in some big saloons, with a full suite of parking cameras seeking to cover for the car’s sizeable B-pillars and big, padded headrests (which can be near-impossible to crane your neck around at junctions).

Out on the road, though, the S-Class’s size is less of an issue. It feels wide on some single-carriageway roads, but its overall width is at least easy to judge, and the car is always surprisingly easy to operate and drive at a basic level. Performance, ride and handling all remain geared and tuned very much towards comfort, refinement and smoothness. Soft air suspension delivers the wafting ride that drivers and passengers alike will expect. By and large, this is a very comfy and quiet car.

However, that ride is considerably better on a well-sealed A-road than a craggy urban surface. The 21in alloy wheels and low-profile tyres of our higher-trim-level Premium Plus Executive test car made for good cabin isolation, but not outstanding on-board refinement. They failed to smooth over the sharpest ridges around town, the suspension thumping a little over drains and manhole covers (they can be hard to avoid in a car so big). They also made for a motorway ride that, while very agreeable in the main, could occasionally turn either fussy or slightly coarse, depending on the surface. Smaller wheels can be had, but not if you want a relatively equipment-rich car, and most surely will.

Mercedes’ 2.9-litre turbocharged diesel 400d engine is a good fit for the S-Class, proving torquey, quiet (except when working hard at revs) and real-world frugal, too (40mpg at a fast cruise). All it lacks is much in the way of alluring audible charm.

Pedal response is ever gentle and progressive, and the car’s outright performance level greater than most will regularly tap. Handling is secure, contained and very predictable, delivered through fairly light, filtered, medium-paced, easy-going steering. Although the S-Class will tolerate being hurried along, close body control and particular cornering agility don’t really feature among its dynamic strengths. Frankly, nor should they.

However, more so than the car’s size or how it rides or performs, it’ll be your reaction to the S-Class’s new ‘digitally enriched’ cockpit that will likely decide whether you’ll really get on with it or not. Between its 3D digital instruments, its busy, extra-large augmented-reality head-up display, and its looming 12.9in MBUX touchscreen infotainment system (the first two are options), the car seems to broadcast information at you in something of a distracting onslaught at first.

The 3D instrument display may be novel but it can also be a challenge to focus on, depending on what it's actually displaying at the time. (It's actually got two separate overlaid screens that target your left and right eyes independently.) Meanwhile, the navigation arrows that appear on the head-up display to indicate which exit you need to take at a roundabout, or which side road you’re aiming for, aren’t always as helpful as you might imagine they’d be.