'The demand is there, but supply is a major issue for anyone wanting to buy the most fuel efficient used vehicles,' explained Tim Naylor of BCA. 'A quick look at our online stock locator on just one day found only 78 vehicles for sale throughout our nationwide network of auctions that matched the Fuel-Economy.co.uk list of most fuel-efficient cars. This is fairly representative of the current low availability of these vehicles as used cars and compares to the 12,000 plus vehicles BCA typically has consigned for sale on any given day.'

The Fuel-Economy.co.uk top 10 for the most fuel-efficient diesels and petrol hybrids includes the Citroen C1, C2 and C3 – all 1.4-litre diesel models; the Honda Insight petrol hybrid; the Renault Clio 1.5 dCi and the Toyota Prius petrol hybrid. Its top 10 for most fuel-efficient petrol cars includes the smart Roadster; smart fortwo; Toyota Aygo, Citroen C1; Peugeot 107 and Daihatsu Charade.

Mr Naylor added: 'As fuel prices continue to climb, we expect used values for the most fuel-efficient cars to keep rising as well.'

In fact, the relentless price pressure that motorists are experiencing may well bring about a change in attitudes to "eco cars" according to Mr Naylor: 'Only a very small proportion of motorists we surveyed last year for our Used Car Market Report believed that they would be looking at eco options for their next car,' he said.

'Just 3% said they would buy an electric-hybrid (1% used, 1% nearly-new, 1% new) – a figure that had actually fallen by a point for two years running. But the sharp increase in fuel prices over recent months could convince motorists of the benefits of a higher MPG and lower CO2 emissions in the long run,' he concluded