BMW is the past master of spinning a wide range of different bodystyles from a single model family.

The celebrated 3-series range is a blueprint of how to produce saloon, estate, coupé and folding hard-top convertible models all off one platform. It’s a tactic that’s worked well – so it’s now repeating the formula with the 1-series.

We’ve caught the first photos of the One coupe and cabrio spin-offs cold-weather testing in snowy Scandinavia; BMW is sticking with a fabric roof for its convertible, so there’s a separate fixed-head coupe, rather than combining the two in a folding tin-top CC.

As well as differentiating its open-top baby from the new 3-series Convertible, this helps the 1-series’ packaging; engineers say the boot has decent space even with the fabric stowed.

BMW recently unveiled the three-door hatchback One as part of a mid-life facelift, and the sporty coupé and cabrio duo will roll into UK showrooms in 2008, after launch at a motor show next winter.

Both two-door 1-series models will be offered with engines familiar from the current range. Expect capacities from 1.6 to 3.0, depending on the size of your wallet, and there may yet be an M-badged performance variant for enthusiasts.

It’ll be unusual in this class for being rear-wheel drive, which BMW claims offers the best possible handling. Under the skin the 1-series shares more than half its components with the 3-series, one of the best compact executive cars on sale today.

Design
Regular 1-series hatch meets notchback. Separate coupé and cabrio.

Engines
Familiar petrol and diesel engines from 1.6 to 3.0 litres

Range
1-series will now comprise three- and five-door hatch, coupé and cabrio