THE Toyota Prius is one of the few cars that can lay claim to being part of motoring history in its own lifetime.
Almost 20 years ago it laid the foundations of modern motoring as the first hybrid for the masses.
What started out as a West Coast dream machine in California went on to become an everyday sight on our roads.
Endorsed by Hollywood A-listers and an army of those who wanted to be seen to be green, the Prius gained celebrity status as the car of the future which would help save the planet thanks to its petrol-electric powertrain and low carbon emissions.
Hybrids are now big business and not only do they account for almost a quarter of Toyota's not inconsiderable sales but the technology has been embraced by virtually every big-hitter including Ford, Mercedes and Audi.
Toyota claims that since their introduction in 1997 hybrids have saved motorists some five billion gallons of fuel and with the Prius at the front of the pack it's time to push on.
So here comes Prius number four and with official fuel consumption now rated at 94mpg it is more eco-friendly than ever.
CO2 emissions are down to 70g/km which is nearly half the 120g/km that grabbed the limelight for the Mk1 model.
As such the all new Prius is highly tax effective with an 11 per cent benefit in kind rating for business users, exempt from congestion charges and attracting 100 per cent capital write down allowance.
The new Prius is also rather good to drive with better handling and much more oomph than before.
Gone is that surging sensation under acceleration and the power transmitted through the CVT gearbox now feels at one with the output from the electric motor and the petrol engine.
Total power output is 121bhp with 97 of those horses coming from the 1.8-litre engine which is now one of the most energy efficient blocks around with low friction components and a high thermal rating. Top speed is a claimed 112mph and 0 to 60 acceleration is given as 10.6 seconds.
As with previous generations of the Prius the drive can be switched from normal to sport or eco settings and on the new model the differences in the feel of the car are much more defined.
It can also be driven in a pure electric mode giving zero emission motoring for about half-a-mile in real world conditions - but that's enough to make a mark in traffic, on start up or when parking.
Leave the Prius to its own devices and it is a very easy car to drive, feels more solid than before, is noticeably quieter and will return close on 70mpg without any trouble.
We saw an average of 63 to the gallon on a brisk drive through the countryside and around town it was even more economical showing a shade under 71 to the gallon.
Those real world figures make it the most fuel efficient of any of the previous three generations of Prius we have driven over the years.
A new-style battery assembly - guaranteed for five years like the rest of the car - is slimmer, lighter and more powerful allowing for more use of the electric motor and enabling the Prius to travel as an EV up to 68mph.
The new car has retained the American-style foot operated parking brake of earlier models but the rest of the interior has been thoroughly reworked with a full colour head up display fitted as standard on all but the basic model, a seven-inch touchscreen in the centre of the dash and two digital instrument displays sited centrally.
The cockpit-style layout of the last model has made way for a more open plan approach which includes an exposed centre console complete with a wireless charging pad for the latest breed of mobile phones.
The driving position has been improved considerably and the car is much more comfortable, especially over long distances.
Luggage space has also been increased with boot capacity up to 502 litres - more than 10 per cent bigger than on the Mk3 model - if you opt for a tyre repair kit in lieu of a spare wheel. With a spare, luggage space drops to 457 litres and maximum capacity with or without the spare is a generous 1,633 litres.
The Prius can be shod with either 15 or 17-inch rims - the bigger wheel reducing its official fuel return to 85.6mpg and pushing emissions up to 76g/km.
It is slightly longer than before but sits lower and is the first example of Toyota's so-called New Global Architecture which will span several models using more standardised components.
The Prius still looks very futuristic, sleek and aerodynamic with a pronounced rear spoiler that now starts in the side of car before crossing the tailgate bisecting the rear window.
Toyota has gone for avant-garde shapes for the front and rear lamps clusters - both LED - and the design is a standout feature day and night.
Pricing for the new model is almost unchanged with the four trim line-up starting from £23,295 but now topping out at £27,450 with extra specification arriving higher up the range.
Standard equipment includes plenty of high tech stuff such as automatic cruise control and lane departure warning systems as well as an air conditioning system which is clever enough to know which seats are occupied and adjust its operation accordingly, reducing energy use and boosting fuel economy.
More smart kit arrives on the bottom but one Business Edition models which get blind spot monitors and cross traffic sensors as well as the head up display for the driver and the wireless phone charger for an additional £900.
A further £800 brings in sat nav and automatic parking in the guise of Business Edition Plus grade.
Top specification Excel models which are aimed more at the private buyer, come with leather trim and upgraded sound systems plus automatic wipers while option packs are available across the range and include rear seat entertainment equipment such as DVD players.
The top two trim levels come with the 17-inch alloys as standard but for those wanting the extra economy instead of the added style the car can be specified with the smaller wheel - and Toyota will knock Â£400 off the overall price.