SOMETIMES it's the details that count; the little things that show how much care has been lavished on a car to make the driver happy.

In the case of the latest Toyota Prius - fourth generation of the biggest selling petrol/electric hybrid to date - it came down to the way the armrest on the door and between the seats had been positioned with millimetric precision.

Precisely placed to allow both elbows to rest while hands clasped the steering wheel at a semi-textbook twenty-to-four position.

And so relaxing; like the rest of the Prius in fact. With its electric motor often letting the car pull away in silence for a little way before the petrol engine chimes in softly, this is a pleasant way to travel long distances.

Ideal when the car has to carry a tired driver and navigator-in-chief home from Heathrow after an anything but relaxing few days away.

There can be no more easy-going way to manage the tribulations of the M25 and the M1 than a car that never showed less than 63mpg on its dash readout and looked after gearchanges for you with its smoothly acting auto transmission.

You can still buy an old-style Prius that plugs into a power point to charge its battery before needing to call in petrol power, but the car I drove (and vastly the more popular version) simply charges when you slow down or brake. Doesn't go nearly so far on current alone but is simpler to live with.

Lower, longer and wider than before, this latest Prius is also the most economical and least polluting to date, finding extra room for people and luggage thanks both to the bigger dimensions and a smaller but more powerful battery, now hidden under the rear seat.

Toyota must smile when recalling reaction to the original Prius in 1997. It looked odd and drove unconvincingly - but see the car world today, where everyone is urgently mixing petrol and electricity to match the demands of politicians eager for a greener future.

This latest Prius is aimed at keeping the car green (a little greener, in fact, with lowest ever fuel consumption and emissions) but making the car better to look at and drive.

Well, it certainly looks different, outside and in. A mass of creases and curves tell you this is a car meant to stand out in the crowd. It does, although you'll have to decide it that's in a good way.

Inside, you'll instantly spot the between seats cubby, with cupholders and space for your mobile phone and all in a plastic so white it brought a call of 'bidet' from my crew. Well put together, though, and part of a cabin that's easy to spend time in and properly thought through for the driver.

It doesn't drive like a sports car, and thank goodness you might say. Ease of long term ownership is more important with something as sensible as the Prius, even with its newfound nod to looks.

The newcomer starts at £23,295 and comes in four versions. All have the same 1.8-litre petrol engine, electric motor and auto gears and a safety package that includes adaptive cruise control that slows the car in traffic and accelerates away when the road clears.

It also detects pedestrians and cars ahead and will brake you to a standstill at lower speeds if you're not paying attention. A camera also spots speed limits and posts them on the dash - sometimes getting things wrong.

The rest of the Prius is pretty well right, though, and a convincing way to keep costs down and do your bit to save the planet at the same time.

: 121bhp, 1,798cc, 4cyl diesel engine and electric motor driving front wheels via automatic gearbox

: 112mph

: 10.6 seconds

: 94.1

: 14

: 70 g/km

: 9%

: 5yrs/100,000 miles