Ever since the i8 coupé was launched in 2013, the convertible version of BMW’s plug-in hybrid sportscar had been on the cards. And our spy has now caught what seems to be a near production-ready version of the i8 Spyder undergoing testing in Europe.

The styling remains faithful to the 2012 i8 Spyder concept, which means some notable design changes from the fixed-top. And we don’t just mean the missing bit of roof.

The sloping back window has been replaced by a small upright item, while the rear buttresses flow into two individual spoilers. The roof looks to be a mechanical jobbie, however, it could even be one of those trick folding tops like the new Porsche 911 Targa. The coupé’s 1.5-litre three-cylinder turbocharged engine combined with an electric motor makes 362 horsepower, but this number will almost certainly be upped in the Spyder as well as the updated hard-top (likely to be launched prior to the convertible). We expect the number to easily edge past the 420bhp mark, with the benchmark 0-100kph split dispatched in about 4.0 seconds dead.

The newcomer should also get a lighter, albeit more efficient battery pack, which should further improve the dynamic balance of the car as well as enhance the all-electric driving range beyond the current i8’s 24-kilometre limit. The i8 Spyder will be launched in 2018.