Mercedes-Benz has just been caught testing a 2012 Mercedes-Benz B-Class prototype out in the public. These images show the new model in its most revealing detail yet, showing much of the body, some of the front grille layout and lots of paintwork instead of the typical black covering.

Usually, the more a company reveals on a test mule means the further along development the car is. This B-Class seems to be in almost production guise. The headlight shape looks as though it's finalised, as do the doors and major panel layouts and contours.

Overall though, the next-generation B-Class is very similar to the current model in terms of body layout. It presents a kind of mini MPV design with a short front snout/bonnet and a large rear cargo area with a relatively level roof that extends high right until the tailgate.

This test mule is the hatch variant, a coupe and a convertible are also expected to come out with the new model. It looks like Mercedes-Benz is continuing to develop the hatch version first as there's been no sign of a coupe or convertible test mule yet.

As far as engine specifics go, the new model will be available with a range of small four-cylinder engines, both turbo and non-turbo as well as a turbo-diesel variant. The B-Class is also expected to come out with a hybrid package of some kind which will be in tune with the company's plans to introduce a hybrid version of every model by 2014.

An AMG model is also rumoured to be in the mix sporting a 2.2-litre turbocharged engine producing around 200kW.

The new model is set to be unveiled at this year's Frankfurt Motor Show in September, with production models in showrooms early next year.