Seven Nigerian stowaways detained after British special services stormed an oil tanker off the Isle of Wight have been arrested on suspicion of seizing or exercising control of a ship by use of threats or force, police have confirmed.

The raid was carried out by around 16 members of the Special Boat Service (SBS), backed by airborne snipers, who secured the vessel in around nine minutes.

The operation was authorised by Defence Secretary Ben Wallace and Home Secretary Priti Patel on Sunday night after a tense 10-hour stand-off.

According to maritime tracking websites, the ship reached port in Southampton early on Monday morning.

Hampshire Police said the force was alerted to concerns over the welfare of the crew of the 748ft (228m) Nave Andromeda soon after 10am on Sunday as the ship headed towards Southampton, having set sail from Lagos in Nigeria.

A force spokesman said: “The seven men have been arrested 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. They all remain in custody at police stations across Hampshire.

“All 22 crew members are safe and well and the vessel is now alongside in the port of Southampton. Investigators are speaking to the crew members to establish the exact circumstances of what happened.”

The Ministry of Defence said: “In response to a police request, the Defence Secretary and Home Secretary authorised armed forces personnel to board a ship in the English Channel to safeguard life and secure a ship that was subject to suspected hijacking.

“Armed forces have gained control of the ship and seven individuals have been detained.

“Police investigations will now continue. Initial reports confirm the crew are safe and well.”

The seven stowaways detained are understood to be Nigerian nationals who have been handed over to the force.

The ship’s operator, Navios Tanker Management, said the stowaways “illegally boarded” the Liberian-flagged tanker in Lagos.

“The UK authorities had been advised by the master that stowaways had been found on board and that he was concerned for the safety of the crew due to the increasingly hostile behaviour of the stowaways,” a statement said.

“Happily no crew members were injured and all are safe and well.

“Navios Tanker Management wish to thank all the UK authorities involved in this operation for their timely and professional response.

“Navios would also like to pay tribute to the master of the Nave Andromeda for his exemplary response and calmness and to all the crew for their fortitude in a difficult situation.”

The company revealed on Monday evening that the master, a Greek national, had remained on the bridge throughout the SBS operation in order to stay in contact with them and continue the safe navigation of the ship.

All other members of the crew went to a secure area on the vessel for their own safety, except for the engineer – another Greek national – who remained in the engine room taking instructions from the master.

Prime Minister Boris Johnson said: “I can’t comment on the operational details. Both police and armed forces did a fantastic job and I thank them very, very much for what they did to keep our shores safe.”

Bob Sanguinetti, chief executive of the UK Chamber of Shipping, said: “I think this has got all the hallmarks of a situation where a number of stowaways are seeking political asylum, presumably in the UK.

“At some stage they got aggressive.

“Clearly no-one knew at the time how aggressive they were, whether they were armed or not, what their motives were, because there will have been confusion at that stage.

“In the discussions taking place between the ship’s captain and the authorities in the UK – both police and the military – they will have decided at some stage the least risky option was to board the vessel using the special forces as it turned out in the end.”

The SBS is the elite maritime counter-terrorism unit of the Royal Navy, with most of its personnel Royal Marine Commandos, whose operations are highly classified and not officially confirmed.

When stowaways ran amok on a cargo ship in the Thames Estuary in December 2018, the ship’s operator said they were detained after SBS personnel were airlifted on to the vessel.

On Sunday, four military helicopters – thought to have included two Merlin Mk4s, a Wildcat and a Chinook – took 40 personnel to the scene of the suspected hijack aboard the Nave Andromeda and about 16 members of the SBS boarded the vessel.

“I commend the hard work of the armed forces and police to protect lives and secure the ship,” Mr Wallace said.

“In dark skies, and worsening weather, we should all be grateful for our brave personnel. People are safe tonight thanks to their efforts.”

Ms Patel said: “Tonight we are thankful for the quick and decisive action of our police and armed forces who were able to bring this situation under control, guaranteeing the safety of all those on board.”

Before the armed forces action, Hampshire Police said the vessel had been located around six miles (9.7km) off the coast of Bembridge on the Isle of Wight, adding: “It was reported that a number of stowaways were on board and they had made verbal threats towards the crew. No-one has been reported injured.”

An exclusion zone with a three-mile (4.8km) radius was placed around the vessel, with two Coastguard helicopters spotted circling the ship in the afternoon.

It is not yet known exactly when the stowaways were discovered but Mr Sanguinetti said: “It might have been entirely friendly for a number of days with the crew looking after the stowaways.

“But clearly, as the ship got closer to the UK, the stowaways got a bit more agitated and aggressive and that’s when the captain would’ve felt the crew of the ship were being threatened.”

He added: “I think what’s heartening from all of this is that the UK has sent a very, very clear message that ships and seafarers will not be allowed to get caught up in crises of asylum seekers or economic migrants.”