PLUG-in sales are plummeting, according to the man from Lexus. Well, he would say that wouldn't he since the company and its parent Toyota specialise in self-charging hybrids.

But here's the thing. There is verified research that highlights how customers buy plug-in cars, plug them in for the first couple of months, get bored and end up using them simply as internal combustion vehicles - thereby defeating the whole object of the emissions exercise.

Lexus can therefore allow itself a small smile of smug satisfaction that no matter which of its hybrids it is, there is no need for a plug. No messing with cables, no driving around looking for a charging point and yet you still get the badge for saving the planet.

And so it is with the new Lexus RX 450h, the company's best selling model, and the car that put luxury into hybrid SUV.

Like its stablemates it is a self-charging hybrid. Kinetic power is regenerated by braking or taking your foot off the gas. It is then stored to be put to use when you need it.

And no need even to think about that. By analysing your speed and driving style the car will choose for you when to invoke EV mode - usually in the city - to save emissions.

The only thing that is cushier than that on the new RX is the incredibly comfortable suspension. You just glide along as if you are in the biggest, comfiest seat in your house.

The electric motor is paired to a 3.5-litre petrol engine with a CVT gearbox delivering a combined power of 313ps.

It is a swift and smooth drive as the electric motor kicks in initially to send you on your way by delivering instant power from both energy sources.

And then that suspension takes over settling you in as you put your foot down to enjoy the drive.

The fourth generation RX SUV emerges into the 2019 market, not greatly changed, but subtly tweaked to keep fans happy and attract new customers to this big, robust - but elegant - vehicle.

For this is the strength of Lexus, big and beautiful.

The RX carries the deep grille that immediately identifies the marque outlined in chrome and bookended by the new Bladescan headlights. The rear is sculpted with an integrated spoiler, the hatch electrically operated and a chrome skidplate finishes it all off.

Inside, as befits the king of the hybrids, the interior is plush and very luxe.

First off, there is simply loads of room no matter where you sit but particularly in the front where I reckon even a great big rugby player would feel comfortable.

The roominess is repeated in the rear seats and even in the third row on the RX L where there are two extra seats creating marvellous carrying power for all the family. In the seven seater Lexus have even installed buttons to move the seat backwards and forwards to adjust the legroom by 95mm.

The new RX comes with a full suite of upgraded safety features in the Lexus Safety System+. The Pre-Collison Assist recognises pedestrians or other vehicles on the road, day or night. The Active Steering Assist, in appropriate circumstances will drive around a collision hazard and the Adaptive High Beam System maximises forward visibility without dazzle.

To this Lexus have now added Bladescan for even greater night time visibility by projecting light to a lens which can expand the area ahead to be illuminated.

Amazingly Lexus celebrate their 30 birthday this year with the good news that more and more people are opting for hybrid cars. More than 95 per cent of the cars they sell are hybrids.

So much in demand are they that there is a dedicated battery factory at Kokura in Japan. Between Lexus and Toyota the manufacturing facility has turned out more than 13 million batteries in the last three decades.