Thirty-three-year-old Martin Leen was convicted in a Special Narcotic Drugs and Psychotropic Substances court in Mumbai last weekend, but his lawyer, Ayar Khan, says he is "shocked" at the verdict and that he is "very optimistic" that an appeal to the High Court will be successful.

Leen was arrested three years ago, in May 2004, by the Indian Air Intelligence Unit while preparing to board a flight to Zurich. The prosecution alleged that 12kg of hashish was found in his check-in luggage.

However, the judge in the case said in open court that it was very doubtful as to whether the seizure was recovered from Leen's bags.

The Irish national was convicted solely on the basis of a confession he made that was subsequently retracted. It is understood that Leen's defence team will present material as part of its case in the appeal that will show the confession was not given voluntarily.

A second man standing trial alongside Leen was acquitted due to lack of evidence. Leen's statement, which he subsequently retracted, said that this man had supplied him with the drugs.

However, in acquitting the man, the judge chose not to accept this part of Leen's confession, raising inevitable questions as to why only this aspect of the confession was deemed unacceptable.

One observer told the Sunday Tribune that officers giving evidence at the trial contradicted each other on a number of issues, including the timing of the seizure, and that independent witnesses produced by the prosecution did not support the case that the drugs came from Leen's bags.

Khan said Leen was understandably very upset about the judgement, but insists that he was not in possession of the drugs and definitely wants to appeal.

That appeal could take up to a year to be heard.

A spokesman for the Department of Foreign Affairs said the Irish embassy was offering consular assistance to Leen.