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Toyota didn't invent the hybrid car - that accolade belongs to Porsche's founder back in 1896 - but it's the Japanese car maker that has done more than anyone to further its cause.
Twenty years since it was first launched, and following three generations and more than nine million global sales, the word 'Prius' has become synonymous with 'hybrid', and diesel's recent fall from grace mean they're more relevant than ever.
Based on the non plug-in Prius launched last year, this version gets a longer, more streamlined and eye-catching body.
Underneath that distinctive skin are new lithium-ion batteries that, after a two-hour fast charge, offer up to 39 miles between charges - significantly more than the 25 miles some of its rivals can only manage - and all without the range anxiety of a pure-electric vehicle.
A more refined powertrain
Engineers say they have refined the hybrid powertrain in every way possible. For the latest Prius plug-in, that means it gets a new battery warmer for cold conditions and a special cooling system for hot weather to prevent any sudden power loss - an affliction even modern smartphones can suffer with.
Even more exciting for technophiles is that Toyota will also soon offer an optional (£1,500) solar-powered roof option that, even in the UK, gives 400 free miles a year. The result, the Japanese car maker claims, is a small hybrid hatch that beats all others for efficiency, hence Toyota claiming it will average 283mpg and emit just 22g/km of CO2.
At the time of writing, whole life costs for this latest plug-in Prius were yet to be announced, so we're unable to tell how it's going to fare against rivals like the A3 e-tron or the BMW 330e, but these headline figures put it at the top of the pile.
To justify its premium over the regular Prius, Toyota has loaded even the lower-spec Business Edition trim Prius with loads of standard kit including adaptive cruise control, an 8-inch infotainment system with sat nav and safety kit like lane departure warning.
Inside, like the regular Toyota hybrid, is a clean, uncluttered cabin that trades a premium feel for functionality.
So far, so good then, but climb behind the wheel and the case for the Prius Plug-in starts to become slightly less convincing.
Combined, the hybrid system and 1.8-litre petrol engine only produce 120hp. That's only enough for a 0-62mph time of 11.1 seconds and a top speed of 101mph. Off the line, you really notice the extra 150kg the plug-in system adds over the standard car.
Things are actually better when running on pure-electric power, but that alone isn't enough to haul you up steep motorway inclines, where the petrol engine has to kick in and work hard to deliver its modest performance.
Toyota deserves praise for the seamless transition from electric to petrol power. But it's a shame the artificial-feeling E-CVT transmission emphasises the sound of a hard-working petrol. Engineers, however, say there's nothing more efficient to transfer the power to the front wheels.
Unfortunately, the braking system still leaves a little to be desitred too. It's difficult to brake smoothly, a lot of which is due to the hybrid system's keenness to recover energy to charge the batteries.
Also, points are deducted for the way the Prius Plug-in drives. Simply put, it's not as involving as many considerably cheaper petrol or diesel hatches, or its closest plug-in competitors.
Priced near to rivals like the Audi A3 e-tron and BMW 330e, the Toyota has a problem on its hands: despite being significantly more efficient, a typical user will pay the same in benefit-in-kind company car tax as the faster and much better-to-drive Audi and BMW so its difficult to recommend.
Toyota Prius Plug-In Excel
P11D £33,330 (before £2,500 Govt. grant)
On sale March 2017
Fuel consumption 283mpg
CO2 (BIK band) 22g/km (7%)
BIK 20/40% per month £39/£78
Boot space (min/max) 360 litres
Engine size/power 1,798cc/120hp
Low monthly tax bill
Small diesel hatch could still offer better mpg on motorway