IN the world of electric vehicles bigger batteries mean more miles and that is exactly what is happening with the new Nissan Leaf.

It is the best selling EV on the planet, it's built in Britain and it is about to become the first battery powered compact hatchback that can travel 155 miles on a single charge.

That's a 25 per cent improvement over the current model and we have just put the new Leaf through its paces on a gruelling mountain drive which is used as part of the Monte Carlo rally.

The hairpins on the road to the Col de Turini are notorious and the 45 mile run rises from sea level to more than 5,000 feet.

It's a severe test for any vehicle but for an electric car the gradients pose a serious, power sapping challenge.

We set out from Nice in a recently charged new Leaf which was showing a theoretical range of 140 miles.

By the time we reached the top of the Col some 90 minutes later the Leaf's onboard power display was showing the batteries had been drained to 33 per cent of their capacity and the available range had fallen to just 45 miles.

With a return journey of 50 miles still to come it seemed an impossible task - until you get to grips with the vagaries of electric motoring.

Since the route back to Cap Ferrat just outside Monaco was downhill the Leaf quickly clawed back the miles.

With regenerative braking boosting the batteries on the go, within 20 miles the batteries had been charged to 55 per cent and the distance available had shot up to 95 miles - enough to complete the journey without any so-called range anxiety.

But there's more to come and because life on the road in the Leaf is not the norm it completed the trip with 38 per cent power and 52 miles still remaining.

Do the math, as they say and the real world performance of the new Leaf on one of the hardest drives imaginable was not far off what Nissan claims.

It's estimated to cost just 2p a mile to run the new Leaf which is a fifth of what it costs to fuel an average diesel car.

For drivers who don't face long daily journeys electric cars are becoming more credible and for many a single charge - which costs around £3 - would last the best part of a week.

The new Leaf is the third generation of Britain's first mass produced EV in the past five years and shows how fast Nissan is moving with battery technology.

In the new Leaf the potential of the lithium-ion battery pack has been increased from 24 to 30kWh which means it can store more power, although charging times remain the same - 30 minutes from a quick charger and around eight hours for a full charge at home.

Performance is also unchanged with the Leaf accelerating from 0 to 60mph in 11.5 seconds and a top speed of 90mph.

On the road it feels lively enough and is as straightforward to drive as any automatic - albeit an absolutely silent one.

Compared to the original Leaf of 2010 it is much more refined and the latest models are now fitted with the Nissan Connect multimedia system which includes sat nav and smartphone connectivity which allows for some of the car's functions - such as air conditioning the cabin prior to start up - to be controlled remotely via apps.

And to help with power use the car is fitted with a solar panel on the top of the rear spoiler to capture natural energy to support the 12-volt battery system which powers the Leaf's conventional equipment.

The new Leaf is priced from £24,490 which includes the Government's £5,000 grant for electric vehicles and costs £1,600 more than current 24kWh model which is remaining on sale although upgraded inside with the new connectivity system.

Nissan says that with the bigger battery the Leaf is good for an extra 19 school runs and for those who use the zero emission car as a taxi it is the equivalent of an additional 10 fares on one charge.

Nissan's Sunderland factory, which produces the Leaf alongside the Qashqai, Juke and Note now employs 6,700 workers and also manufactures the batteries for the 24kWh car.

The new batteries are sourced from Nissan in Japan although still assembled in the North East for European markets.

The warranty for the latest generation battery pack is also being increased to eight years and 100,000 miles compared to the five year guarantee Nissan offers with the second generation Leaf.

Leaf sales in Britain are now approaching 12,000 which makes it the top selling EV in the UK ahead of the likes of the BMW i3, the Kia Soul EV and the Zoe which is produced by Nissan's sister company, Renault.