Diesel and petrol demand is almost static from the 2011 report, at 27% and 45% respectively, but has yet to catch up with the sales split among new cars. The report also showed a fall in demand for hybrid and alternative fuel vehicles, including electric models, down from 3% in 2011 to 2% in 2012.

Diesel cars, which are usually more expensive than their petrol counterparts, are likely to be affected by buyers’ preference for choosing based on price. This was considered the most critical factor when buying used, with 41% of those surveyed saying it was top of their priorities. Fuel source accounted for just 12% of responses.

Yet 27% said they would be looking to buy a more fuel efficient car as the economy recovers, the highest deciding factor, while 20% were aiming for lower road tax.

Report author Professor Peter Cooke from the Buckingham University Centre for Automotive Management, said: ‘The fleet market is very much enamoured with diesel, but the used car buyeris much more interested in petrol as a power source. And if we’re going to see price hikes in fuel it’s going to bring in all sorts of implications.’

The UK remains Europe’s biggest used car market, and its total value reached £35.7bn in 2011 based on transaction values, the highest on record and an increase of £2.4bn on 2007 figures. Fleet and leasing disposal volumes are expected to drop rapidly this year due to the after-effects of the banking crisis in 2009, falling from 495,000 in 2011 to 415,300 and not predicted to rise again until 2014, the report says.