The latest Alliance & Leicester New Car Price Index compiled by the Centre for Business & Economics Research says after three years, upper medium are worth 40.2% of their original price — 14.4 per cent lower than the average for all cars, and that the Laguna and Omega are the best three-year old bargains. However, the Index indicates a marginal improvement in upper medium residual values compared to last year's reported figure of 39.8%. Within the upper medium segment the latest Index reports that the Renault Laguna and Vauxhall Omega have the lowest residual values, the Laguna being described as the best used car buy after three years at a value of £4,906, 31.1% of the price paid three years ago. The Renault Laguna moves from a Index residual 6.0 per cent above the family car average after one year, to one that's 9.0 per cent worse than the average by the third year in the latest A&L figures, but Renault UK has pointed out that its compilers failed to note that the one and three year old Laguna models mentioned above are new- and old-shape models respectively. Renault issued a news release describing the Index published this week as “deeply flawed and inaccurate”, adding, “It is common industry knowledge that Alliance & Leicester surveys about car depreciation cannot be relied upon for accuracy and many members of the media will not rely on them.”