These latest spy shots of the all-new Smart ForTwo and ForFour were taken in northern Sweden as the next-generation of fuel-efficient city cars underwent some essential winter testing. Built in collaboration with Renault, the rear-engine, rear-wheel drive models sport new Daimler platforms, with the four-door variant expected to spawn a new Twingo and possibly a Nissan-branded car as well. Even though the cars are being developed simultaneously, the ForTwo will be rolled out first, hitting the market sometime in 2014.

Smart will offer the two-seater with a range of petrol and diesel engines as well as a fully electric version, while the ForFour is due out in 2015. And while these prototypes remain heavily disguised - with some fresh body panels and some apparently borrowed from Renault hatchbacks - their styling cues are expected to be borrowed from the Smart Forstars concept unveiled at the Paris Motor Show.