Mercedes-Benz is hard at work developing a convertible version of its SLS AMG supercar.

The drop top gets a folding roof in place of the fixed hard top while the gullwing doors are expected to be replaced with conventional ones. Official details are not yet available but the prototype has been snapped undergoing testing in Germany so work seems to be on progress.

Recently images from the German patent office have revealed sketches of the SLS AMG Cabriolet hinting at further development. The car is expected to match the coupe’s specifications including the 563bhp 6.2 litre V8 engine and is expected to be launched as a 2012 model.