Demand for used diesel vehicles is growing, with cars attracting higher prices at auctions and selling four days quicker than they did last year.
The figures, released by Cox Automotive, contrast with the new car market, where diesel sales are 28.2% down.
Used Petrol cars were reported to stay on forecourts for two days longer than they did last year.
At Manheim auctions, the average sold price continues to increase - up 3% from £6,649 in May to £6,816 in June - while wholesale volumes in the £10,000 to £20,000 price bracket experienced a double-digit growth of 16% reflecting the demand for quality, mid-market vehicles.
Diesel wholesale volumes reflected the overall increase in the mid-range (£10k to £20k) price bracket with a 14% year-on-year increase.
Cox Automotive's Philip Nothard said: "Ready-to-retail cars remain in huge demand and continue to attract top prices and conversions, with less interest in basic models which need more conditioning.
“The supply and acquisition of the right stock remains one of the biggest challenges for the wholesale market going forward, especially in terms of ex-lease vehicles, where we are seeing a surge of similar models coming through the lanes creating price pressures. Vendors who can differentiate will do well as we go into the second half of the year."