Road Test: Mitsubishi Outlander 2.0 PHEV GX3h 5dr Auto

Forget what you think you know about dirty great 4x4s, because Mitsubishi has destroyed the cliché and created a green SUV poster-boy - the Outlander PHEV. No need to fear abuse from Toyota Prius drivers, because with a theoretical combined fuel consumption of 148mpg and CO2 emissions of just 44g/km, this fully functional SUV has better stats than a Prius plug-in.

In fact, those figures make it the most economical SUV in the world, and the reason for this lies in the plug-in hybrid system - a 2.0-litre petrol engine with 119bhp, combined with twin electric motors (one on each axle) pushing out a total of 60bhp and 245lb ft. Which also has the handy side effect of making the Outlander PHEV properly four-wheel drive. Either system can also be declutched and used to recharge the batteries.

It's also possible to run the Outlander on electric-only for up to 32.5 miles - again, a theoretical figure - and when the batteries are depleted, the petrol kicks in. Think of it like that Toyota Prius, only with more emphasis on electric-only driving, and you'll be
about there.

But what about the real-world figures, we hear you cry - surely no one will ever get near 148mpg. True, but the worst we ever saw was 60mpg, and that included a section of motorway. Impressive, bearing in mind this thing weighs 1,810 kg.

Given that the boot is just three per cent smaller than the diesel's and it can tow 1,500kg and easily seat five, it seems that Mitsubishi has created the perfect family SUV.

All of which could, initially, make the verdict seem harsh. But dig deeper, drive further, and there's a problem with the execution of all this technology. It's added 200kg to the kerbweight, so the PHEV doesn't ride as well as the diesel. And the petrol engine rasps asthmatically when it kicks in, for very little gain in performance.

Which is a great shame, because we really wanted to like the PHEV, especially as there's no price penalty for going green. Including the £5,000 government subsidy, the PHEV is exactly the same cost as the diesel version. And because the emissions (and therefore tax) are so low, Mitsubishi says that company-car drivers can save nearly £11,500 over three years compared with, say, a Honda CR-V. Not a small sum. Is it enough to overcome the shortfalls? Only just.