Values failed to climb as usual during spring and reached a peak well ahead of seasonal norm, the publisher has said.

Record-high supplies of convertibles to the UK have affected values and the credit crunch has lessened demand of these items that are considered luxury. Jeff Paterson, chief car editor at EurotaxGlass’s, said that up until 2007, used convertible values would normally rise by around 10 per cent between March and early June, holding steady through to early August. “This year and last the pattern has become very different,” he said. “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.” Paterson continued that the increased supply of convertibles within the used car market was due to the record numbers registered in recent years. He said sales of new convertibles had consistently exceeded 100,000 each year since 2003, reaching an all-time record tally in 2004. “These cars are now arriving on used car forecourts in sizeable numbers and greater choice inevitably puts pressure on values, especially now that demand is easing back,” said Paterson.