The expanded Wrangler line-up offers more on-road comfort and day-to-day practicality than ever, and it manages to achieve this without sacrificing Jeep’s famous off-road abilities. This spacious four-door model has a unique appeal, while the new 2.8-litre diesel engine is another welcome introduction to the range. The Wrangler is a truly charismatic off-roader, and the new model is the best version yet.

The Jeep Wrangler Unlimited will become the world’s only four-door production convertible when it hits dealers next year.

Along with a traditional two-door model, the Unlimited is part of an all-new Wrangler line-up that also includes a fresh 2.8-litre diesel engine. Jeep claims the unit is so good, it will account for 99 per cent of all UK sales.

Outside, trademark styling cues include the famous seven-slot grille and round headlamps, plus a fold-flat windscreen, exposed door hinges and rugged bonnet catches.

All models in the range come with Jeep’s three-piece ‘Freedom’ roof. This comprises a pair of rigid panels above the front seats that can be individually removed and stored inside the car. At the rear, a large canvas top folds down and sits on the rear deck.

The latter section is bulky but lightweight, and taking it off transforms the chunky off-roader. There’s still a beefy rollcage for protection, but if you need more exposure, simply lift the doors off their hinges for the ultimate in open-air motoring.

Climbing aboard is easier than before, with no awkward sill to negotiate. Once inside, luxuries such as electric windows all-round will be unfamiliar to owners of the existing car, as will the wide range of adjustment on the driver’s seat and generous shoulder room – 14cm more than its predecessor.

An extra 52cm between the wheels makes the Unlimited a genuine five-seater, and there’s even a large 1,315-litre boot.

Head off-road, and the Wrangler has lost none of its prowess, with high and low-range four-wheel-drive ratios helping it in the rough. The length of the four-door model hinders mud-plugging compared to the short-wheelbase car, but few owners are likely to bother to find out by how much.

On road is where the biggest gains have been made. Refinement on the motorway is impressive, and for such a boxy shape, wind noise is restrained. So is tyre roar, which is notable for its absence at high cruising speeds.

Admittedly the diesel engine is raucous under acceleration, but the Wrangler can keep up with traffic and the five-speed auto gearbox is smooth and responsive. Body roll is also well controlled. Weak points include the steering, which although much improved over its predecessor is still vague around the straight-ahead. Standard ABS and a three-stage ESP system – which can be disengaged for off-road work – combine with six airbags to boost safety.

The Wrangler is aimed at motorists in search of a stylish and durable off-roader, and it’s full of character. You can forgive it almost anything – noisy diesel engine included.