According to Glass's Information Services' new quarterly Car Market Index, the poorest performers were the Daewoo Tacuma, Renault Scenic and and Citroen Xsara Picasso, respectively worth 41%, 40% and 39% of their value new after three years/36,000 miles.
The best performers were the Kia Carens (45%), Nissan Almera Tino (45%)and Fiat Multipla (44%).
Glass's puts the massive drops down to the greater volumes now available at this age and noted that – relatively – residual values are still strong.
It added: 'Looking at the situation in comparison to last year it can be seen that values are currently £950 lower, an increased rate of reduction compared to the position three months ago when values were £700 lower.
'This is a situation we expect to continue as many more recently-launched models enter the used market, thereby increasing availability in this growing sector.'
Aross all sectors, prices are slipping. The Car Market Index revealed that the average three-year-old vehicle with 36,000 miles is worth £5,762. By next month, the valuation experts at Glass's expect this to fall to approximately £5,677.
It said: 'Values have reduced by 4.8%, or £380, over the last three months and this downward trend is expected to continue into the summer.
'However, average used car values for 2004 are higher than for 2003 and the overall scenario for values of used three-year-old cars remains reasonably positive.
This trend is expected to be maintained in the short term while interest rates remain low, house prices continue to rise and the consumer-spending boom shows little sign of abating.'