First ride: 2020 Mercedes-Benz GLA prototype

Mercedes confirms the new model is almost 20mm shorter than its 4424mm-long predecessor. Despite this, the wheelbase has been extended by 30mm to 2729mm, endowing it with greater rear leg room and the scope for an adjustable rear seat similar to that already offered as an option in the B-Class and GLB.

The biggest change in overall dimensions, however, comes with the height. It has been increased by almost 100mm, giving the GLA less of a hatchback-on-stills optic in favour of a more dedicated crossover appearance. It also helps to provide greater head room, especially in the rear, which is now considerably roomier than before.

Inside, the new GLA combines elements from both the A-Class and GLB. With clear and precise digital instruments, a touchscreen infotainment system housed with a single panel and 64-colour ambient lighting, it's big on upmarket appeal. Standard equipment includes automatic emergency braking, lane-keeping assistance, speed limit assistance, driver attention monitoring and keyless ignition.

With our time in the new GLA limited to an off-road course at low speeds, we can’t tell you much about its character just yet. What we can confirm, though, is that it's capable of going places most prospective owners will never consider taking it.

As with other new Mercedes compact models, its optional 4Matic four-wheel drive system has been re-engineered to offer fully variable apportioning of power to either the front or rear wheels. Traction on slippery surfaces is obviously a key strength, allowing it to climb and descend tricky obstacles without much trouble at all.

Despite Mercedes' insistence on showcasing the GLA's off-road ability, though, it will only be offered with standard bodywork. A more rugged variant in the style of the company’s All-Terrain models isn't on the cards, according to Mercedes representative Markus Nast. He says the new model, which goes under the internal codename H247, will be available exclusively with a standard or, in combination with an AMG bodykit, lowered ride height.

The engines for the new GLA mirror those of the other Mercedes compact models. Exclusively four-cylinder, they include 1.3-litre and 2.0-litre petrols delivering 163bhp and 225bhp, plus a 1.5-litre diesel with 114bhp and a pair of 2.0-litre diesels developing 148bhp and 187bhp.

Standard GLA models will retain front wheel drive, while gearboxes are set to be a six-speed manual and a seven-speed automatic Getrag or eight-speed dual-clutch Mercedes unit, depending on the engine. 

A new GLA 250e EQ Power plug-in hybrid will join the new GLA line-up shortly after the beginning of sales in the UK next summer. It uses the same powertrain as the recently introduced A250e EQ Power, with a 1.3-litre four-cylinder petrol engine and gearbox-mounted electric motor developing a combined 215bhp. With a 15.6kWh lithium ion battery mounted underneath the rear seat, it's expected to provide an electric-only range of more than 40 miles on the WLTP test cycle.