Manheim market analysis for vans reports average values were 0.9% higher year-on-year for the period June 2011 to June 2012, despite average age being five months higher and mileage increasing by 4,767 miles.

But part of the cause is likely to be demand for low supply as sale volume levels were almost a third lower than the same period in 2011.

Looking at the monthly figures in more detail, average wholesale used van values rose by 1.7% to £4,194 in June, compared with £4,123 in May, despite average mileage continuing its upward trend, by 314 miles to 80,829 miles.

Although the year-on-year selling price shows an upward trend, six of the eleven segments measured showed a drop in value between May and June.

The fall in values seen in the key volume markets - car derived van, small panel van and large panel van over three tonnes - was most apparent in small panel vans where the average selling price for this vehicle dropped by 9.5%. This indicates a possible correction in the market.

James Davis, director of commercial vehicles at Manheim Remarketing, said: "Average sale prices have risen for the ninth month in succession. The conversion rates have softened and the trend for used van inflation shows little sign of disappearing.

"Supply and demand anomalies, combined with the summertime seasonality factor, mean that rare and clean vehicles will still attract interest, but poor quality stock in high volume is likely to sit around for longer as traders’ focus on cash flow in quieter times of retail activity.

"Many independent dealers who are buying for stock during the summer will consider buying two or three lower value vans rather than tying up cash flow in one higher value younger van.

"Comparing online with physical sales, there is a clear trend for younger, lower mileage vehicles to be cherry picked and fought over by online buyers battling against the hall bidders. However, like physical auctions, the online sale prices have remained stable throughout the last 12 months despite age and mileage increasing."