The captors of the Alakrana and her 36-strong crew seemed to have abandoned the tuna fishing boat amid rumours that a ransom has been paid, and this is not being denied on official circles. The crew are all unharmed.

The Spanish prime minister declined to comment to questions about a  ransom, rumoured to be 2.3 million euros, but added that the 'government did what it had to do'.

A spokesman for the pirates said: 'We have reached an agreement with Spain and all parties are happy. Most of the group have now left Alakrana and the rest of my group will abandon the boat in the next few hours.'

He also said there was an agreement on the release of two of the suspected pirates captured by a Spanish frigate and brought to Madrid for trial. The pirates had threatened to kill the fishermen unless the two were released.

The Alakrana has now returned to sea, escorted by two Spanish naval vessels.The vessel was seized more than 350 nautical miles north-west of the Seychelles island of Mahe in early October.

The incident also led to a political row when the Madrid Government at first refused to allow armed guards on their fishing boats in the Indian Ocean. They eventually relented after it was learned that the French had placed marines on some of its trawlers and they had successfully repelled pirate attacks.