The Land Rover Freelander 2 TD4_e is the greenest car Land Rover has ever built.

It marks Land Rover’s first step to create greener cars, and boasts a Stop/Start system which automatically cuts the engine when the car is stationary.

Similar systems might already be available on conventional saloons and hatchbacks, but the Freelander TD4_e is the world’s first four-wheel drive to feature Stop/Start.

Stuart Milne took a Freelander TD4_e from Heathrow to the centre of London’s financial centre - via a custom-built off road course in the disused Battersea power station.

SUVs aren’t the first vehicles that spring to mind when thinking of eco-focused cars. It's partly thanks to this bad reputation that Land Rover is embarking on a programme of developments which will ultimately see it producing a 60mpg+ SUV developing less than 100g/km of CO2.

Fitting its baby Freelander with Stop/Start technology might not seem like the most significant development, but improving fuel consumption and emissions on its most popular model will make a huge impact.

The complexity of these systems shouldn’t be understated, which partly explains why no one has fitted Stop/Start to a four-wheel before.

The on-paper benefits are clear to see. Land Rover says it improves fuel consumption by around 4.5mpg, and reduces CO2 emissions by 8 per cent.

That last figure means the Freelander TD4_e drops from 194g/km to 179g/km; which adds up to a £40-a-year saving based on 2008 road tax prices.

And Land Rover has calculated that a £680 fuel saving is possible over non Stop/Start-equipped Freelanders. Official tests say fuel consumption is reduced from 37.7mpg to 42.2mpg.

The Stop/Start model replaces the standard manual 2.2-litre diesel Freelander, and despite the obvious potential for cash saving at the pumps, the Land Rover Freelander 2 TD4_e doesn’t cost any more than the model is replaces.

The Freelander TD4_e has been developed as part of Land Rover’s e_Terrain Technologies programme. Jaguar-Land Rover has invested a staggering £800m in sustainable technologies, which will see various hybrid models hitting the roads over the next few years.

Land Rover was keen for this green technology not to interfere with the on-road dynamics the Freelander offers, and the off-road ability the brand is famous for.

The Stop/Start system works seamlessly on the road. It shuts the engine down when the car is stationary in neutral and the clutch pedal is raised. To restart, all the driver need do is press the clutch pedal. It can be deactivated at the press of a button is desired.

The system will only activate when the engine is warm and if the battery is up to the job. That particular component is an Absorption Glass Mat Battery, which can work longer and harder than the conventional lead acid batteries found in most cars.

When it comes to exploiting the Freelander’s surprisingly competent off-road abilities, the system shuts down depending on the grip mode selected. The Freelander offers various different modes which adjust the chassis characteristics depending on the surface to be tackled.

We put the Freelander to the test in and around the disused Battersea power station, over a variety of obstacles.

And the good news is the new eco-system has affected none of the car’s mud-plugging power. For a soft-roader that’s likely to spend most of its time on the road, it is wonderfully competent.