The restructuring of the BMW line-up, which sees the latest 3 Series-based coupe and convertible become the 4 Series and the equivalent replacement 1 Series models transformed into the 2 Series, will be completed by the end of this year.

The 2 Series coupe goes on sale early in March and a convertible will be confirmed and shown in either concept or production form at one of the major auto exhibitions before year's end. BMW will also add a convertible 4 Series to its line-up next month.

That means all BMW saloons, estate cars and hatchbacks will have odd-number model designations while coupes and convertibles will have even-number badging.

But it is not set to stop there. At the Geneva Motor Show BMW will unveil the 2 Series Active Tourer and the 4 Series Gran Coupe.

The first of those is a compact premium sporty hatchback to rival the Mercedes-Benz B-Class. Unlike other 2 Series models, which are rear-driven, the Active Tourer - based on the platform of the new MINI - is transverse-engined and has front-wheel drive.

Both are firsts for BMW, and contrary to everything the company has always championed - rear-drive and a 50:50 weight distribution. However, BMW is adamant that front-drive will not be a factor for buyers.

"The rest of the class is front-wheel drive and we expect 75 per cent of customers for the Active Tourer to be new to BMW, so the driven wheels will not be a factor in the buying decision," says small cars product manager Alex Morgan.

"A few years ago we did some research and something like 80 per cent or 90 per cent of 1 Series buyers didn't even know which wheels were being driven. We have 10 years' experience of front-wheel drive with MINI, and I don't think many people would be critical of the way they drive. There might be a few purists who object , but we don't expect it will be many and our volume aspirations are very sensible."

The Active Tourer is set to arrive in the UK in September, three months after the 4 Series Gran Coupe. This will be a four-door fastback, similar in concept to, but smaller than, the 6 Series of the same name.

Before then BMW's booming UK sales - up 41 per cent on last year so far in 2014 - will get the twin fillip of the 2 Series coupe and 4 Series convertible.

The UK was the second-largest market in the world for the old 1 Series coupe, with 30,000 sold in its lifetime, and the replacement is larger, better-equipped and more practical for a price rise of less than 1 per cent.

Britain will also be the joint-third most important market for the folding-top 4 Series - we bought 27,000 of the last-generation 3 Series convertible. Here, too, there are upgrades in usability and specification for a small price increase of between £375 and £495.