The new BMW 1 Series is a five-door hatchback that thinks it is first cousin to a roadster. It is not a two-seater, nor is it a convertible — yet — but it has the long bonnet, cabin set well back and stretched wheelbase that are distinctive signatures of BMW’s own Z4 roadster, and of its earlier Z3-based M coupé. The 1 Series is BMW’s idea of what a compact, premium hatchback capable of carrying out all the traditional family car chores should look like — and it continues the BMW tradition of rear-wheel drive and a choice of fine engines.

“The car has been designed to be the most agile, the most perfect in steering and handling — to be different to all other cars on the market,” Dr Burkhard Göschel, a member of the BMW main board, said. This focuses not only on dynamics (to get a 50:50 weight balance front and rear, the battery is tucked away beneath the boot floor), but also on sporty styling, and prestige. The new baby reflects the criteria that are central to the success of its siblings.

Styled in concept form at BMW’s Californian Design Works, its sculpted, almost razor-edge looks are distinctive, but not as daring as the 5, 6 and 7 Series, which is probably a good thing. Like other BMWs, it doesn’t photograph well and needs to be seen on the road for its aesthetics to be appreciated. It will certainly hold its own in the street-cred stakes and will look svelte and modern next to lumbering, matronly 4 x 4s.

But the 1 Series, on sale here from September 18, does not pretend to top the charts in terms of interior space. Even getting into and out of the back seats is a struggle for adults. This compromise packaging is the penalty of its roadster/coupé-like styling, rear-wheel drive and a north-south positioned power unit that sits way back in an engine bay that is just waiting for a big six cylinder. Luggage room is reasonable, with probably sufficient room for a goodhumoured Labrador. The rear seat is divided and folding.

All this, though, is only part of what BMWs are about. The real core of their success is superb dynamics: road-holding, handling and performance. The 1 Series is up with the best of its peers, although it did not give me quite the tingle that I had anticipated.

It sweeps through difficult corners with flowing precision, the steering is super-sharp, the six-speed manual gearbox (there is an auto option) light and quick. But I found the 2.0-litre petrol-engined version almost apologetically quiet and refined. Much more interesting and characterful was the powerful 2.0-litre, 163-bhp turbo-diesel, with 340 muscly Nm of torque. The range starts with the £15,690 116i, 1.6-litre petrol with 115 bhp, 0-62 mph time of 10.8 seconds and average 37.7 mpg.

Standard equipment across the range includes six airbags, run-flat tyres, on-board computer, CD player, dashboard stop/start button and lots of electronic chassis safety support systems. Options include the controversial BMW iDrive — thankfully simplified, because the car has conventional, commonsense climate controls instead of a set of totally unnecessary on-screen graphics, so it is possible to work out how to be warm or cool before reaching the end of a journey.

Pneumatically adjustable backrest side supports for both front seats are a worthwhile option. I spent five hours driving the car, with not so much as a twinge of backache. The 1 Series is an important car for BMW. In its first full production year about 150,000 will be built, but that figure is set to rise as other variants are introduced, and when sales start in the United States.

If you thought the 3 Series had become commonplace, just give the 1 Series a couple of years. It’ll be everywhere.

IN DETAIL

Engines: 1.6 (116i) and 2.0-litre (120i) petrol; 2.0-litre diesels (118d and 120d). Power: 1.6: 115 bhp; 2.0 150 bhp; 2.0 diesel, 122 bhp or 163 bhp.

Performance: Petrol: 1.6: 0-62 10.8 secs, top speed 125 mph, average 37.7 mpg; 2.0: 0-62 mph 8.7 secs, top speed 135 mph, average 38.2 mpg. Diesels: 2.0 (designated 118d) 0-62 mph 10 seconds, top speed 125 mph, average 50.4 mpg; 2.0 (120d) 0-62 mph 7.9 secs, top speed 137 mph, average 49.6 mpg.

CO2 emissions: 1.6, 181 g/km; 118d 150 g/km; 120i 178 g/km; 120d 152 g/km.

Prices: £15,690 to £20,800 — trim levels, Standard, Sport, SE.

On sale: September 18.

THE RIVALS

Volkswagen Golf: Dependable, quality product, understated. More enjoyable to drive than it used to be. Great diesels: fast 2.0 GT TDI 138 bhp — £18,530 for 5-door.

Audi A3: Premium compact, good looking, fine handling. Sportback five-door comes in September (prices from about £16,500); new 2.0-litre 200 bhp turbocharged direct injection petrol engine.

Alfa Romeo 147: Stylish, fine engines with 3.2 V6 the powerful star (£22,750) but only in three-door; five-door from £13,850 for 1.6 Twin-Spark petrol. 1.9 turbo-diesel, quick and well mannered, £15,450 as 5-door.

Ford Focus: Phenomenally successful, outstanding handling. Hatch, saloon, estate; five-door hatch from £11,695 for 1.4 CL to £17,000 for ST170. Due to be updated this year, but a hard act to follow.