The purchase of low-emissions vehicles such as electric cars is to be subsidised for another two years, the Department for Transport has announced.

The move aims to encourage more than 100,000 motorists to choose more environmentally friendly cars.

A grant of up to £4,500 can be claimed against the cost of the cleanest vehicles – up until March of 2018.

As well as providing a boost for the UK's burgeoning electric car market, the £400m funding scheme will also help clean the nation’s air.

The government has been criticised in recent days for being slow to make the UK compliant with EU NOx limits quickly enough.

The extension of the grant could see the number of hybrids and electric cars on UK roads treble. The funding policy has supported the purchase of 50,000 low emissions vehicles since it was introduced in 2011 and was set to conclude early next year.

Carmakers were pleased with the announcement: Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, said: “Manufacturers are offering increasing numbers of these vehicles – but a consistently applied incentive regime is still needed over the coming years to help consumers adopt these ground-breaking technologies.

“The changes to the regime will need effective management and SMMT looks forward to working with government to ensure the planning needs of manufacturers and consumers – both fleet and private – are met.”

From March 2016 owners of ultra-low emission cars who installed their own domestic charge point will also receive a £500 grant – covering about half the average cost of such a device.

The transport minister, Andrew Jones, said: “We are determined to keep Britain at the forefront of the technology, increasing our support for plug-in vehicles to £600m over the next five years to cut emissions, create jobs and support our cutting-edge industries.”