THE display screen showing the energy flowing between the engine, electric motor and battery became a strangely addictive focal point of my family’s time with this hybrid vehicle.

“Are we running as an Electric Vehicle (EV)? How much has the battery recharged?” came the inquisitive voices from the back seats, where my children had become transfixed with the clever technology dictating how the Lexus RX450h should be powered.

All my previous attempts to explain hybrid powertrains in words had prompted glazed looks but, suddenly, it was all crystal clear thanks to real-time graphics that responded to my every throttle input with a green arrow going one way or a red arrow going the other.

“Get it back onto EV, we’re saving money, see how far we can go as an EV”, came the instructions from my impressionable young passengers.

As well as encouraging me to drive with a light right foot, the discussions inside the Lexus cabin that day were a microcosm of the wider battle for hearts and minds that must be won if the move towards eco-friendly vehicles is to happen as quickly as the Government seems to desire.

In the fight to make green technology fashionable, mainstream and appealing, Toyota and its luxury arm Lexus have been pushing the boundaries harder than most. Indeed, the Lexus RX was the original hybrid SUV, forgoing the accepted diesel powerplants to offer buyers something different, with a cleaner battery-boosted petrol engine under the bonnet.

A holiday in the south-west and a trip to the Dartmouth Steam Railway gave ample opportunity to compare our ultra-modern luxurious vehicle with the form of transport that whisked my granddad and grandma to the West Country in the 1940s when my family first embarked on our now-annual pilgrimage from West Yorkshire to Devon.

Now in its fourth generation, the improvements to the RX seem set to maintain the vehicle’s reputation for comfort, style and reliability. One area in which the latest RX has been improved is that of design. Its sharp creases and curves link it to the upgraded styling on other recently-launched Lexus models such as the IS, NX and RC.

The front end of the new RX is characterised by a powerful new interpretation of Lexus’s signature spindle grille, contained in a chrome-finished frame and flanked by LED headlights. It all adds up to a handsome vehicle, which boasts a stronger and more athletic body style than before.

Once behind the wheel, it’s an enjoyable experience all-round. If you happen to lose patience with attempting to remain in EV mode, a hearty push of the accelerator awakens the 3.5-litre direct injection V6 petrol engine, which can take you from a standing start to 62mph in a mere 7.7 seconds - rather impressive for a sizeable machine.

The re-engineered powertrain creates a system with a total output that’s risen from 295bhp to 308bhp when the power of the engine and electric motors are combined.

The only slight drawbacks are the sluggish throttle response from the CVT gearbox and the sense that there’s a fair amount of body roll in corners.

During a week in the vehicle’s company, I found the fuel economy to be excellent, although it seldom came close to the official combined figure of 51.4mpg.

Inside, the spacious cabin has a refined feel. Standard equipment on all models includes heated front seats, climate control, a user-friendly eight-inch display screen and a DAB radio system. This model comes with a number of extras, including auto-dimming mirrors and ventilated leather seats with a memory function.

With a price tag above £50,000, it’s competing against some strong rivals, but its dynamic looks, ease-of-ownership and clever powertrain are enough to make it stand out from the crowd.

The Lowdown

Lexus RX450 Luxury

PRICE: £52,290
ENGINE: V6 24-valve DOHC with VVT
PERFORMANCE: Top speed of 124mph and 0-62mph in 7.7 seconds
FUEL CONSUMPTION: 51.4mpg combined
EMISSIONS: 127g/km

Will's Ratings

ECONOMY: *****
SPACE: ****
VALUE: ****