The highlights are a new 2.0-litre diesel for the 220d and, for the first time in a BMW convertible, and an M Performance power unit for the M235i.

The diesel produces 190 PS and 400 Nm of torque – CO2 emissions are 124g/km for the manual and 116g/km for the optional eight-speed automatic. Combined fuel consumption is 60.1 mpg for the manual and 64.2 for the automatic.

The M Performance 3.0-litre six in the M235i produces 326hp and 450Nm of torque, enough for a 0-62 mph time of 5.2 seconds for the manual gearbox and 5.0 seconds with the automatic. Combined fuel economy is 33.2 mpg in the manual and 35.8 mpg in the automatic; CO2 emissions are 199g/km and 184g/km respectively.

The remaining petrol engines are both 2.0s, one badged 220i (184 PS), the other 228i (245 PS).

Three trim levels will be offered – Sport, Luxury and M Sport trim – although the M235i has its own unique specification. SE models will be available later on. The new car goes on sale from 28 February, 2015 and is priced from £29,180 for the 220i Sport Convertible.