The successor models to the existing first-generation BMW 1-series coupé and cabriolet have been spied testing just over a year before their planned UK showroom debut.

Set to adopt a new 2-series nameplate as part of BMW’s plans to provide greater differentiation between its volume-selling saloons and hatchbacks and their coupé and cabriolet siblings, the new two door pairing, codenamed F22 and F23 respectively, have been extensively re-engineered in a move that sees them grow incrementally in size, providing them with increased levels of interior accommodation and luggage capacity together with improved safety credentials.

The heavily disguised prototypes caught here testing in Germany provide few clues as to the look of the 2-series coupé and cabriolet, although BMW sources suggest they will follow the example of the recently unveiled 4-series by adopting a more individual appearance than today’s models, albeit with various exterior design elements from the second-generation 1-series hatchback. One obvious design element is the retention of a fabric hood on the cabriolet pictured here.

The 2-series coupé and cabriolet are based around the same mechanical package as the second-generation 1-series hatchback, alongside which they will be produced at BMW’s Leipzig factory in Germany. Key among the changes is the adoption of a modified platform. It uses a 30mm longer wheelbase and supports front and rear tracks that have been extended by a significant 55mm and 60mm respectively. It has also been engineered to support both standard rear- and optional four-wheel drive.

Among the engines set to power the new 2-series are turbocharged 1.6- and 2.0-litre four-cylinder direct-injection petrol and 2.0-litre four-cylinder common rail diesels together with a turbocharged 3.0-litre in-line six-cylinder, which in range-topping form is expected to provide a 235i M Performance range topper with 320bhp.