Longer, wider and roomier inside than the old model, it still has BMW's trademark longitudinally mounted engine and rear-wheel drive. New features include an ECO-PRO fuel-saving mode, revised diesel engines and two all-new 1.6 twin-turbo petrol units with 136 and 170bhp respectively and emissions under 140g/km CO2.

The diesel range will include a 118d and 120d, both of which emit less than 120g/km with no performance sacrifice – the 120d passes 62mph in 7.2 seconds. These will be joined by the most efficient BMW car to date, the 116d, shortly afterwards. Featuring congestion charge dodging 99g/km emissions, it will be priced from £20,195.

Other highlights include optional driver assistance systems and mobility services such as High-beam Assistant, Adaptive Headlights, Park Assist, Reversing Assist Camera, Lane Departure Warning including Collision Warning, cruise control with brake function, speed-limit and no-passing information.

In addition, the latest ConnectedDrive system offers internet connectivity, smartphone and music player integration, real-time traffic information, as well as web radio, Facebook and Twitter apps.

The new 1 Series goes on sale on 17 September, priced from £19,375 for the 116i ES.