HPI interviewed 150 UK second hand car dealers and found that 72 per cent had seen an increase in customer awareness of CO2 emissions.

Lower tax was identified by 54 per cent as the reason for the change, well ahead of the 30 per cent that cited impact on the environment and the 28 per cent that saw better operating economy as the biggest influence on CO2 emissions awareness.

Some independent car dealers complained of difficulties sourcing emission-friendly superminis at auctions because buyers for car supermarkets have dominated the market for this stock. “Our research shows that used car buyers' attitudes are changing more rapidly than expected,” said HPI automotive director Daniel Burgess. He said the survey “represents a good cross section of dealers across the UK and within the used car market.”

RMIF chairman Alec Murray said the impact of environmental concerns on used car buying habits were “negligible,” and that cost factors usually drove buying decisions. Other factors identified by the HPI for the rise in customer awareness of CO2-related issues included higher taxes for high emission cars, pinpointed by 25 per cent, media coverage, rising costs, an increase in diesel sales and the high profile London congestion charge. Some 79 per cent of dealers said they hadn't seen an increase in demand for cars as the petrol/electric Toyota Prius Hybrid.

However, the halo effect generated by the Prius for its brand saw Toyota top the list of car makers seen as leading the way over green issues. Some 49 per cent of respondents saw Toyota as the leading brand in this field, followed by Honda at 20 per cent, helped by its Civic IMA petrol/electric. Volkswagen was third on 5 per cent. Four out of five dealers claimed their premises were environmentally friendly, with 49 per cent saying they recycled paper and glass, and 41 per cent saving energy through turning off lights and heating.