Liberian-registered oil tanker, Nave Andromeda, was captured off the Isle of Wight coast on its way to Southampton on Sunday morning.
The seizure made headlines around the world and forced a daring night-time raid from the Royal Navy’s elite commando force, the Special Boat Service.
Now Portsmouth-based naval veteran Ian Millen, who is a maritime security adviser to EOS Risk Management, has claimed the crew could have known about the stowaways days earlier.
The former Royal Navy Commander pointed to a series of suspicious manoeuvres made during the ship’s transit past the west coast of France could have indicated ‘something was wrong’.
He added: ‘There will be an investigation into how the stowaways got on board and how they remained undetected for three weeks, but it is possible that the stowaway incident just came to a head yesterday and may have been ongoing for many days.
'Reports of the vessel’s situation emerged yesterday, but knowledge of the stowaways and attempts to deal with them may stretch much further back into the three-week voyage from Nigeria.’
As previously reported, the seven men are believed to have sneaked aboard the 42,000-tonne tanker in Lagos, Nigeria, on October 5.
But violence only erupted when the crew reportedly tried to lock the stowaways in a cabin on Sunday morning prior to handing them over to UK Border Force in Southampton.
Threatened, the ship's 22-strong team retreated into a ‘citadel’ on the tanker – a safe room – and issued a desperate mayday.
The plea sparked a 10-hour stand-off in the Solent with police until eventually authorities were forced to call in the military for help.
Sixteen SBS operators were scrambled to retake the tanker, flying in two blacked-out Royal Navy Merlin helicopters and two Wildcat helicopters.
The special forces team stormed the vessel in a ‘textbook’ operation, taking just seven minutes to secure and detain the wannabe hijackers.
None of the crew were injured during the assault and all seven of the stowaways were later arrested.
Defence secretary Ben Wallace said there had been a ‘threat to life’, adding: ‘We were under the awareness that the suspects were also threatening to do something with the ship.’
Mr Millen, a former trustee of the Human Rights At Sea charity, said the 22 sailors would have been shaken up by the ordeal.
The naval officer – who is the chief executive of Veterans Outreach Support, a Portsmouth charity which help ex-military personnel and merchant navy veterans – added: ‘This is a clear example of the dangers faced by our international seafarers, who keep our lights on and put food on our tables, operating around the world in some dangerous places.
‘It is, however, ironic, that having operated and sailed from the world’s most dangerous maritime region, the Gulf of Guinea, the Nave Andromeda’s crew would never have expected to find themselves in the middle of a special forces operation to save them, just five miles off the Isle of Wight.’
Hampshire Constabulary said the seven men were being held on suspicion of ‘seizing or exercising control of a ship by use of threats or force under Sections 9(1) and (3) of the Aviation and Maritime and Security Act 1990’.