THE NEW INSIGNIA is essentially a whole new car - with the emphasis on car. Rather than take on any of the high-rise, slidey-seat trappings of the booming crossover style, the Vauxhall has gone the other way: it’s not just longer and wider than the old car, it’s also lower. If the body style is very traditional, the rest of the car is all modern, going big on small-cc turbocharged engines, touchscreen interfaces, electronic safety aids and connectivity. The hatchback is now called the Insignia Grand Sport and arrives in the UK in June. It’s followed a few weeks later by the estate, called the Insignia Sports Tourer, which has the same choice of petrol and diesel engines. There’s no saloon version.

The car we’ve driven is the hatchback with the more powerful of the 1.5 turbo petrols, here in the second highest of the seven trim levels. All but the most basic Insignias are well specified; the entry-level model lacks alloy wheels and sat-nav, but comes in at £1500 cheaper than the nearest equivalent old Insignia, starting at £17,115 on the road.

Much of the technology and construction know-how is derived from the current Astra, and posher versions get an even better version of the Astra’s LED lighting. The result is a car that (depending on engine and spec) weighs in at up to 175kg less than its predecessor.

The petrol engine range includes two versions of a new 1.5 turbo and a 2.0 turbo (which has allwheel drive). The turbodiesel range involves two 1.6s and a 2.0. Your gearbox choice is six-speed manual or eight-speed auto - lighter and more compact than the old six-speed auto.

From the outside, it looks significantly different - a bit Volvo S90, a hint of Mazda 6 - while still being unmistakably a big Vauxhall. The lights are narrower, there’s a sharp crease on the aluminium bonnet and along the sides, and the wheelbase is longer, with the front wheels positioned further forwards and the rears further back. The benefits of this are most obvious when you drop into the back seat. It’s got usefully more legroom, and a bit more headroom despite the coupe styling. In the front it’s slightly more roomy than before, but the focus is on making you feel in rather than on, a bit like a traditional Jaguar set-up. The view down the long bonnet emphasises this. On the road, it’s no Jaguar. It’s at its best when you’re breezing along a suburban ring road: it’s calm and composed, with a smooth manual gearbox and comfort-orientated suspension that makes light work of poor road surfaces, and it steers reasonably fluently. But when you up the pace you find an excess of body roll through corners, and a lack of precision to the steering. And when you work the engine hard, it’s horrible. At around 4000rpm the turbo four feels strained, and you find there isn’t much grunt in reserve.

At higher revs and higher speeds it gets noisy in the Insignia. You wonder if they’ve gone way too far in weight-trimming; a bit more sound deadening would restore some refinement. The climate control is intuitive and effective, helped by the use of an optional electrically heated front windscreen (once found only on Fords). Apple or Android phone connectivity comes as standard, as does a connection to the OnStar rescue and information service (although an annual subscription is required after your free three months). Some of the switchgear is bizarrely small and fiddly - things you use every day, like the volume control on the steering wheel. But there’s a clear logic to the distinction between physical knobs (for adjustments you’ll make on the move) and touchscreen controls (fiddling at a standstill). The shelf at the bottom of the screen, for resting your fingers on, is a neat touch.

The Insignia Grand Sport is a mixed bag, but largely a disappointment. I suspect it might all make more sense in the estate, where we’re promised a bigger and more usefully shaped luggage space, as well as the hatch’s improved rear leg room and spec upgrades.