Lewis said: "I have no axe to grind with the Jockey Club as they were given the result by the laboratory and had to take the steps they did. I hope something is learnt from this."
Scientists at the HFL are investigating how two different results can occur. Deterioration of the sample from the time it was collected in August to the second test in December may have caused the discrepancy.
The HFL director, Neville Dunnett, said he hoped that all counter-analysis, which became mandatory from this week, will in future be completed within two to three weeks. "The results in this case are disturbing but not surprising," he said. "It is a sad fact of analytical life, especially with the time period involved."