BMW will unveil an eco concept car at March’s Geneva motor show featuring future technology that will be added to its popular Efficient Dynamics package.

The German brand is keeping details of the car secret until the show, which kicks off at the start of March.

However, BMW has confirmed it will also display a 320d convertible and a 125i coupe at the show.

The 320d convertible will be available in both SE and M Sport trim levels and uses the same 177PS 2.0-litre diesel engine from other 320d models in the 3-series range.

This will give the convertible a 0-62mph time of 8.6 seconds and a top speed of 139mph.

The car will also feature Efficient Dynamics technology to keep emissions low, including stop-start technology on manual cars giving the open-topped 320d a 53.3mpg average and CO2 emissions of 140g/km.

Going on sale in the UK in March, prices start from £33,110 for the SE car.

Alongside the 320d will be a new addition to the 1-series coupe range – the 125i.

The 125i, also going on sale in March, is powered buy a 218PS 3.0-litre petrol engine and is capable of 0-62mph in 6.4 seconds. BMW also claims a 35.8mpg combined figure with a CO2 output of 190g/km. Prices start from £23,195.