The pirate ‘mothership’ sunk by the Indian Navy in the Gulf of Aden last week was actually a Thai fishing boat that had itself been hijacked and whose crew was tied up below decks.

The destroyed vessel, which was blown up by INS Tabar, an Indian frigate, on the night of November 18, was the Ekawat Nava 5, a trawler – not a floating armoury loaded with ammunition and explosives as India had claimed.

Wicharn Sirichaiekawat, the manager of the Bangkok-based Sirichai Fisheries, the ship’s owner, said that the true story emerged when one of his crew was found alive, adrift in the Indian Ocean. Fourteen others are still missing and at least one is dead.

The story was confirmed by the International Maritime Bureau, the marine watchdog.

The news is an embarrassment for India’s navy, which had won international plaudits for taking the fight to the Somali pirates terrorising the Suez Canal trade route. The incident is likely to trigger a review of the terms of engagement by the maritime forces patrolling the Indian Ocean, which include the Royal Navy, security experts said.