Used convertible values are dropping because of the over-supply of new vehicles and the overall economic downturn, according to RV experts at Glass’s Guide.

The market has failed to perform its normal summer upturn for the second year running.

According to a spokesman for Glass’s, “lacklustre trade and retail demand has meant prices have been rising by half their normal level during spring and, despite the onset of warmer weather, they are now starting to slide”.

Values of used convertibles usually rise by around 10% between March and early June and then remain static until August.