This prototype Range Rover undergoing testing is understood to show the progress being made to productionise a parallel hybrid version of the next generation of Britain’s best-selling luxury car.

With the promise of a CO2 rating below 150g/km, the Range Rover hybrid is likely to make a big impact in the luxury car market when it launches around 2013/14.

The giveaway on this prototype is said to be the alloy-framed dark box positioned behind and below the rear bumper where the spare wheel would normally be fitted.

See the spy spics of the new Range Rover hybrid

This is a convenient location to package hybrid parts on a prototype, although in production a more protected position, possibly inside the car, would be preferable.

Under the skin the powertrain of the Range_e model, previewed in a Range Rover Sport body at the Geneva motor show earlier this year, is expected to feature an electric motor in place of the torque converter of the eight-speed ZF transmission.

Similar Bosch-supplied parallel hybrid tech is used by Porsche on the hybrid Cayenne and by Volkswagen on its Touareg.

Read more on the all-new Range Rover

This Range Rover is understood to have been in the hands of Bosch engineers when scooped by our photographer.

A prototype Range_e that Autocar drove earlier this year featured a 69kW electric motor and a 14.2kWh lithium ion battery with plug-in technology. The production Range_e is understood not to feature plug-in tech, saving 
weight and complexity.

The plug-in battery pack weighs in at a hefty 200kg, which would eat up much of the 450kg weight saving that the new alloy body construction will bring to the new Range Rover.

Julian RendellRead Autocar's Range_e first drive

See all the latest Land Rover reviews, news and video