Millions of electric vehicles will be needed over the next 20 years if the UK is to achieve its climate change targets, WWF-UK says.
According to the group's figures, at least 1.7 million electric vehicles (EVs) will be required by 2020 and 6.4 million by 2030 if the target of an 80 per cent reduction of carbon emissions by 2050 is to be met.
Government subsidies and other incentives will be needed to help get the necessary number of EVs on the road - a minimum of one in 17 cars by 2020 and one in six by 2030, the WWF-UK said.
The Government has already introduced a 25 per cent grant, up to a maximum of £5,000 for EVs, but the vehicles still remain extremely expensive.
In a report, WWF-UK said the highest levels of EV uptake would lead to very significant reductions in UK fuel demand, representing over £5 billion a year in avoided oil imports.
Also in the highest case scenario, the combination of extensive EV uptake, driving less and improving internal combustion engine vehicles could potentially reduce UK fuel demand by 80 per cent and deliver a 75 per cent reduction in car emissions by 2030.
WWF-UK campaigns director David Norman said: "It is vital that people start consuming and travelling less to make a transition to a low-carbon economy and reduce our dependency on oil and emissions from cars.
"Road transport accounts for 40 per cent of petroleum products consumed in the UK so a switch from conventional cars powered by petrol or diesel to EVs would have a much-needed impact on reducing fuel demand."
Transport Minister Norman Baker said: "Decarbonisation of road transport is a key priority for this Government. We want Britain to be a global leader in designing and using electric cars.
"That is why we are providing over £400 million to kick start the market including grants of up to £5,000 for electric cars and setting up charging points across the country.
"We are confident that this investment will revolutionise the way we drive and in the future make a significant dent in the UK's carbon footprint."