New figures released by auction house BCA have shown a 0.5% month-on-month drop in average used-car values to £5,633 in July, reflecting the typically weak demand during the summer holiday months.
The July figure was 2.6% lower than the corresponding period in the previous year.
There was a 5.5% fall in sold volumes last month, indicating weak summer activity.
Figures also show an increase in demand for older, lower value dealer part-exchange cars last month, while there was a further decline in fleet and lease values.
Tony Gannon, communications director at BCA, said: "The summer months are typically a time of slow demand and reduced activity in the retail car markets and this is reflected in the wholesale used car sector.
"While there are, of course, worrying signs from the economy that will not have helped, it is not unusual for values to fall back in the peak summer months."
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