The firm's latest Market Analysis for Cars reports that fleet values fell by just 0.1% (£5) to £6,255 in May. This compares to a 3% (£211) fall in overall average wholesale used car values to £6,808 in May. When compared with May 2010, with average age up by three months to 53 months and mileage up by 4,721 miles to 54,698 miles, average wholesale used car values are 7.0% (£516) lower.

Notable examples of decreases in average values in May in the Fleet sector include Small Hatchbacks down 1.3% (£58) to £4,342, Medium Family down 5.0% (£285) to £5,414 and MPVs down 8.8% (£657) to £6,831.

Examples of increases in values for the Fleet sector in May include Compact Executive up 3.5% (£291) to £8,667 and 4x4s up 2.1% (£261) to £12,884.

Mike Pilkington, managing director, Manheim Remarketing, said: 'The fall in retail demand can no longer be attributed to a hangover from the extended holiday period and as we approach the summer months there is likely to be continued downward pressure on values and conversion rates. We are starting to see some stock in short supply which will help protect values in specific sectors but this challenging market is expected to continue for the foreseeable future.'