WHAT does a Rolls-Royce and Vauxhall's new green MPV have in common?

Well, it isn't the price and with Rollers struggling to do half of the new eco Meriva's 63mpg, it's not going to be fuel consumption either.

The clue is in the doors - rear ones, to be specific.  The unorthodox rear-hinged concept may seem a novelty but it is a far more practical and sophisticated set-up than the one used in the Rolls-Royce Phantom and Ghost more than half a century ago.

Vauxhall has perfected the idea, with the rear doors sweeping back to almost 90 degrees so that you have superb access, which takes the latest Meriva to new levels of commonsense and functionality.

It's a godsend for rear passengers who don't have to contort themselves - on one foot - before launching themselves into their seats. They can step in quite easily and naturally. Equally, transferring or retrieving items from the rear cabin is a much more civilised affair.

It's also a "first" where the rear-hinged doors open independently without the need to open the front doors first, as in the Mazda RX8. 

For safety, the Meriva rear doors cannot be opened if the car is moving more than 2mph. And there are other safety features which prevent children opening the innovative FLexDoors when moving.

You cannot fail to be impressed by this sensible arrangement as well as the FlexSpace seating system which enables you to jostle/slide/fold seats quickly and easily and the clever FlexRail centre storage console, but it is the green makeover of the latest Meriva ecoFLEX - without sacrifice to performance - which really impresses and adds icing to the cake.

Powered by a 1.3 CDTi engine, the 95ps diesel unit shows surprising agility. It seemed to have the muscle of a 1.4, if not a 1.6 and felt quicker than the officially quoted 0-62mph dart in 13.8 seconds, though it does need encouragement at low speeds around town.

The ecoFLEX tweaked engine with variable geometry turbocharger, married to taller gearbox ratios, reduces emisisons to a CO2 of just  of just 119g/km, compared to the straight 1.3 diesel unit at 129g/km, while it achieves almost 63mpg average consumption instead of 57.6mpg.  Every little helps!

The Meriva range now comprises of three petrol and four diesel engines with prices starting at £13,000 for petrol versions and from £16,875 for diesel versions. 

The model driven here was the Exclusiv version of the 1.3CDTi ecoFlex with an on-the-road price of £18,720, which may seem expensive, but offers a whole raft of standard features.

They include FlexDoors, FlexRails, FlexSpace seating, electronic park brake, power/heated door mirrors and front windows, air con, ESP, cruise control, full airbags, CD 400 player with MP3 format, Aux-in & USB connections, graphic information display, remote radio controls ..... the list goes on.