IN THIS PREVIEW An embarrassing leak What's new Performance figures revealed

A Slovenian early-draft of a marketing brochure for the new 3-Series has been leaked by an unknown source. A BMW UK spokesman told 4Car: "The background of this incident is under investigation. I'm not saying its industrial espionage at this stage, but clearly, it's a funny business. This is not an authorised document, nor is it an official leak on our part."

The document, slickly produced and as detailed as any showroom brochure, offers an unprecedented level of information about the new 3-Series. Diagrams show that the new 3-Series is longer and wider than the car it replaces. Crucially for interior space, the new car's wheelbase, at 2760mm, is stretched by 35mm compared to the current car. In particular, there is more legroom in the rear. And for even better stability, front and rear tracks are 1500mm and 1513mm wide respectively, an increase of about 20mm. At 4,520mm long, the new E90 3-Series is 30mm longer than the current model. It's a full 60mm wider, at 1817mm to the edge of the body, and virtually the same height, at 1424mm. So the new 3-Series will definitely be more spacious inside, and model for model, it'll be about 100kg heavier.

Design not as controversial as some recent BMWs

The exterior images show that the car has a simpler taillight design than had been expected, as well as a nose that echoes the family look, with strong undertones of the 6-Series in particular. The styling also features style elements introduced throughout the range by BMW design chief Chris Bangle, such as the deep swages down the car's sides, and a dynamic short-front, long-tail profile.