Motorists have been shunning the offer of Government subsidies to buy an electric car, ministers have admitted.
Three years ago former transport secretary Philip Hammond set aside £400 million to enable people buying ultra-low emission vehicles to apply for a grant of up to £5,000.
But so far just £33.5 million has been claimed and it is feared that by the time the offer ends next year some £170 million will still be unclaimed.
The RAC says the figures highlight a "continuing consumer suspicion" about electric cars.
RAC Foundation director Professor Stephen Glaister says confidence in 'plug-in' vehicles would be given a big boost if more interest was shown by businesses and fleet buyers.
He added: "The good news for drivers thinking of going green is that there is plenty of grant money left in the pot for them and the underlying price of these vehicles is gradually falling."
The Government had expected the grant scheme to attract at least 8,600 claims in its first year, but up until the end of 2013 just 6,709 were made in total.
Subsidies of up to £8,000 for low-emission vans are also available but over the last two years just 404 applications have been lodged.
Copyright Press Association 2014