MINI is going greener than ever with two new diesel engines that achieve CO2 emissions of 99g/km.

And the company is also introducing its first MINI Convertible powered by a diesel engine.

It is part of a complete range makeover which kicks in during September and comes hot on the heels of the new, more economical petrol engines announced in the spring and the forthcoming MINI Countryman. 

Following the March introduction of more efficient petrol engines for the MINI range, two all new diesel engines make their debut in the revised and refreshed line-up.

The 1.6 litre units go into the MINI One D and Cooper D, both achieving the same fuel consumption of 74.3 mpg and CO emissions of 99 g/km - a record for any series production car produced by the BMW Group.

The Cooper D Hatch accelerates from 0-62 mph in 9.7 seconds and goes on to a top speed of 123mph, while the less powerful MINI One D Hatch (90hp as compared to the Cooper D's 112) still reaches 62mph in 11.4 seconds and hits a top speed of 115 mph.

In addition to the high efficiency, the new diesels employ technology like Brake Energy Regeneration, Auto Start-Stop, Gearshift Indicator and Electromechanical Power Steering.

The MINI Cooper D Convertible joins the range in August using the same 112bhp engine as the Hatch. It accelerates to 62mph in 10.3 seconds and can reach a top speed of 121mph.

Nonetheless it still sips diesel at 70 mpg and emits just 105g/km of CO2, making it the lowest emitting and most economical ‘full' convertible vehicle on the UK market.

All existing MINI models will benefit from design refreshments. At the front, a new bumper with a lower air intake serves not only to update MINI's face but also to improve pedestrian protection courtesy of larger deformation zones. 

And new style fog lamps adorn either side of the air intake which on MINI One and Cooper features a black cross bar to emphasize the car's low, wide stance.  On the Cooper S two air intakes feed the brake discs.

The typical round MINI headlights also display new light elements, with optional Xenon lamps featuring adaptive headlights as an option. At the rear, there's a new bumper while the tail and brake lights are now LEDs.

Inside, the centre console, steering wheel and the air conditioning and audio controls have all been modified and there are six new upholstery choices.

All radio systems in the refreshed MINI range are equipped with a CD player and AUX-in connection that supports MP3 players and features DAB radio standard across the range with the exception of the MINI First model.

MINI Connected, an optional extra, now offers owners of an Apple iPhone a range of features including web radio, which allows you to listen to any radio station in the world that has a web address, Google Local Search and Google Send to Car.

Prices are expected to be announced soon.