Mr Jenkins said the appeal had succeeded on the technicality but added his clients would remain in custody awaiting the verdict on the second appeal.

Andrew Stow was sentenced to 12 years

The brothers have repeatedly protested their innocence and are trying to get their 12-year jail term quashed.

The pair were found guilty of bringing cannabis into the port at Faro and were sentenced last month - two years after their original arrest.

Andrew Stow, 36, and brother Graham, 41, are now on remand in prison.

On Friday, Mr Jenkins said that if the Stows were subjected to a re-trail under Portuguese law, the proceedings would be presided over by the same judge.

Mr Jenkins said the legal issue was that the Stows' case would be prejudiced by having the same judge and the brothers want the case dismissed.

But the prosecution has countered by seeking a lesser charge of temporary possession of cannabis to put to the two brothers from Milford Haven, west Wales.

Adrian Jenkins: 'No evidence against them'

Mr Jenkins said his clients would not plead not guilty to the temporary possession charge and their eventual release could take up to five months.

During the trial, the court heard the pair set off from Wales in their fishing boat with the dream of setting up a diving school in Portugal.

They had stopped off at the Canary Islands off the Portuguese coast before docking at the port of Faro.

They said they intended to set up a business aimed at the lucrative tourist market.

Portuguese police claimed to find �3m of hashish, weighing 12,000kg, on the bottom of the sea bed as the brothers carried out repairs to their boat, which was in dock.

They were arrested by officers who alleged the brothers had dragged the cannabis across the sea bed using trawler nets.

Graham Stow was with his brother Andrew

Their father, 78-year-old Dilwyn Stow, led a lengthy campaign to have his two sons freed.

He spent thousands battling to prove their innocence and, as the end of their trial approached, he admitted he had reached the stage of possibly having to sell his house to cover their legal fees.

In June, he flew out to Faro to hear that the verdict would not be announced for two months.

They were sentenced two years after their original arrest.