Toyota Hybrid

More than one million people have bought a Prius hybrid since it was launched in 1997, and now the model has reached its fourth generation, with improved technology and efficiency.

Its 1.8-litre petrol engine combines with two electric motors to provide economy of 72.8mpg on the combined cycle and CO2 emissions of only 89g/km. The latter statistic is vital, as anything below 100g/km entitles the owner to free annual road tax.

With the weight of its electric motors and batteries, you might expect the family hatch to struggle on the move. But as both powerplants work together, the car has a peak output of 134bhp – enough to propel it from 0-62mph in a little more than 10 seconds.

In full electric mode, the Prius will run at up to 31mph, while the regenerative braking system allows it to capture energy that would otherwise be wasted when decelerating or coasting. This is then used to recharge the battery. Once the car is stationary, it employs Toyota’s Stop&Start system to kill the engine.

The entry-level T3 model starts at £18,390, and all cars are backed up by the company’s five-year/60,000-mile warranty – so there’s no need to worry about the highly complex drivetrain requiring expensive repairs.

And the Prius isn’t the end of the Japanese manufacturer’s green parade.

The Yaris, Auris, Urban Cruiser and iQ models can all be specified with the firm’s new 1.33 VVT-i engine, which employs a similar Stop&Start system to the Prius.

Models with the most efficient engines and Toyota’s green innovations – such as transmissions that maximise fuel economy – also carry the Optimal Drive badge.

Future eco-friendly innovations from the firm include a full hybrid version of the Auris family hatch, as well as a plug-in Prius. The latter is powered by lithium-ion batteries, which only requires the engine to top up the cells on the move.

BEST ECO BUY: Prius