A RELIABILITY survey that blasts the performance of some modern fleet cars has provoked an industry row amid claims the results themselves are unreliable.

The survey by the Consumers' Association Which? magazine covered 81 models up to two years old, belonging to 34,000 magazine subscribers.

Five models shared the top spot, recording no breakdowns in the previous year. Japanese manufacturers were well represented with the new Nissan Almera, Mazda 626, Mazda MX-5 and the Lexus IS200. The Swedish-built Saab 9-3 held the other top slot.

Among the worst performers was the Land Rover Discovery - 19% of Discovery drivers interviewed said their vehicle had broken down at least once. The Land Rover Freelander came in third from the bottom with 14%.

But the Society of Motor Manufacturers and Traders cast doubt on the reliability of the findings when the size of samples was considered.

A spokesman said: 'For example, the Land Rover Freelander, which according to the survey was one of the most likely to break down, had a sample of 92 from a total vehicle parc of more than 50,000. So the findings could be regarded as not terribly representative.'