The GLC is based on a stretched version of the C-Class’s platform. The interior is based on that of the compact saloon, too, which is a good thing: it’s stylish and well laid-out, with multimedia functionality centred on a slick 7.0in screen and materials from the top drawer of the parts cupboard.
The firm front chairs, which offer plenty of electric adjustment as standard, yield the obligatory lofty seating position, and the generous rear cabin will swallow two adults in comfort; three if you’re among friends. The rear seatbacks split into three, and a powered tailgate is standard-fit, too, giving access to a largely uniform, lip-free boot that matches the X3’s for volume at a useful 550 litres.
At idle, the engine emits only a distant rumble; as revs rise it becomes quite loud, but doesn’t turn coarse. There’s minimal turbo lag, and strong, steady shove is available all the way from 2000rpm to the upshift point just below 5000rpm.
The nine-speed automatic gearbox (the only available transmission) manages progress well. It splashes serenely through the ratios in town, where choosing the drive control’s miserly Eco mode keeps revs low to subdue the engine. Firm suspension disrupts the peace, though, thumping over ridges in a controlled but hard-edged manner that’s exacerbated by our car’s optional 20-inch wheels.
At 70mph in ninth gear, the crankshaft turns at just 1500rpm, and while the engine’s distant rumble persists, the GLC is refined at a cruise save for tyre roar over coarser motorway surfaces.
The car is game for B-road sorties, too. There’s a fluidity to the body control that’s genuinely enjoyable as you leverage the 250 d’s 74lb ft advantage over the 220 d between corners and its traction-bearing four-wheel-drive system through them. Sport mode makes the gearbox’s shifts more aggressive, but there’s still a delay between requesting a manual shift on the steering wheel-mounted paddles and getting it.
The steering is a more serious gripe, though. It’s overly light in Comfort mode, and while it’s responsive enough and there’s more heft to the helm in Sport, there’s a lack of weight variation, which muddies messages of grip from the front wheels. The brakes disappoint, too - they’re certainly effective but have a wooden pedal feel.