The manufacturer has already investigated consumer attitudes to smaller capacity engines, and said most found the sound and power delivery of three cylinder engines appealing.

BMW's first production three-cylinder engine, a 1.5-litre petrol unit with 220bhp, is destined for the i8 plug-in hybrid supercar and will be built at its Hams Hall factory near Birmingham alongside engines for its compact vehicles and MINIs.

Future engine developments will be based on global taxation and emissions regulations, and BMW remains open-minded about its ongoing diesel/petrol sales split. Despite a shift towards diesel across Europe, and with petrol engines fitted to a small minority of its larger models, sales of the latest 1 Series are split almost 50/50 between the two fuels in Europe, slightly in favour of petrol engines and increasingly so, albeit slowly.

The new 1 Series is also future-proofed for technology changes, designed to accommodate a small version of the ActiveHybrid drivetrain fitted to the 3, 5 and 7 Series and the X5 and X6 in some markets. But at the moment there are no plans for a production version due to the resulting loss of boot space in the hatchback. Future models, such as the Coupe, look to be more likely candidates depending on market demand, but with last-generation Coupe and Convertibles still selling well in North America the new model isn't due to include booted versions until around 2014. 

Not all vehicles are being considered for hybrid technology. The new 3 Series Touring, which joins the UK range in September, will not be getting an ActiveHybrid version, and a hybrid 1 Series is lower on the agenda than launching the i electric vehicle range.

There will also be no 320d EfficientDynamics Touring. Although this is available in most of Continental Europe, a spokesperson said fitting the drivetrain to the Touring bodyshell would probably result in CO2 emissions rising to around 112g/km, against the saloon's 109g/km, removing the UK tax breaks which have made the saloon popular with corporate buyers and denting demand.