When the going gets tough, the G-Class proves its worth

The latter is one of the world’s most capable off-roaders. The model dates from 1979 and still retains its flat panels and flat windows which are practical for judging severe terrain.

There are trim upgrades and a new dashboard with the introduction of a colour screen display and “infotainment” system with navigation and internet access. The stability system includes trailer control. New options include blind-spot warning, parking assistance and distance control.

External changes are but light touches. The UK will get only the five-door 208bhp Blue TEC diesel with seven automatic gears, rated at 25mpg and 295g/km. Deliveries begin this autumn, with prices awaited.

The combination of three electrically controlled 100 per cent differential locks, a ladder frame and rigid axles make it so capable in terrible terrain.

The GL-Class is the nearest Mercedes gets to the opulence of a Range Rover. It looks like a large estate so lacks the visual allure but does seat seven. Styling changes are subtle, retaining the upright grille – this time with LED lights and a chromed under-tray for some bling. The 254bhp GL 350 BlueTEC 4 MATIC diesel model, returns 38mpg on the combined cycle, with CO2 ranging from 192g to 209g. Its 0-62mph time is 7.9 seconds.

The GL 500 4MATIC BlueEFFICIENCY V8 petrol version with 402bhp records 25mpg, 262 to 269g/km of CO2 and has a 0-62mph time of 5.9 seconds. Ride and noise refinement on the air suspension is said to be better. It incorporates crosswind mitigation. Deliveries: next year with UK specification and prices pending.

The US-built ML is here now. Prices open at £43,325 for the four-cylinder ML 250 BlueTEC with 201 bhp, combined consumption of 44.8mpg and CO2 emissions from 165g/km, while the V6-engined ML 350 BlueTEC at £46,335 has 254 bhp, 39.2mpg and 189g/km. Both are automatics with stop-start ignition, 19-inch wheels and metallic paint.