The owners of a cargo ship which was hijacked by stowaways from Nigeria have told of the moment the Special Boat Service (SBS) 'stormed aboard' the ship off the coast of Essex to secure the situation.

Paul Kyprianou, spokesperson for the Grimaldi Group, said the operation to contain the stowaways was 'very fast and quick' and that the iron bar wielding men were locked away in a cabin soon after the arrival of the SBS.

When the ship had made contact with the authorities, the engine vessels continued to run and were not shut down by the captain.

'The only thing that happened is when the operation made by the special forces was going to take place, we were asked to switch off the lights, then they stormed aboard,' Mr Kyprianou said.

The Ro-Ro Container ship Grande Tema arrives at Tilbury from Lagos

Grande Tema container ship arrives at Tilbury docks, Essex. The ship was raided by members of the Special Boat Service to detain four Nigerian migrants who threatened the ships crew with iron bars

No-one was hurt onboard following the incident which occurred yesterday afternoon

A unit of elite special forces was helicoptered onto a cargo ship after the men had threatened the crew with iron bars and tried to take control of it.

Four migrants had attempted to take over the Italian ship off the Kent coast, demanding the vessel be moved nearer the shore so they could swim to Britain.

Around 25 members from X Squadron of the Special Boat Service (SBS) - sister regiment to the SAS - were then deployed and stormed the ship as it sailed in the Thames Estuary.

Speaking to LBC Mr Kyprianou said: 'Last night at 11pm we had a special unit of the Special Boat Service – we had 12 men intervening and neutralising the stowaways.

'It was not a piracy situation or hostage situation.'

He added that the crew members had locked themselves away in the bridge of the vessel and that there had been no physical contact between the two groups.

Armed migrants who threatened a cargo ship have surrendered to British Navy special forces who have taken control of the vessel (pictured)

'We sometimes have stowaways but it's extremely rare that they act in this way.

'What they want to do is reach Europe so this is there aim, so I don’t know if they knew they were in the UK, but they knew they were in Europe.'

When asked if the company were reviewing their security policy following the incident Mr Kyprianou said there was a special team and department which were currently dealing with the fallout from the incident.

The stowaways had attempted to take over an Italian ship (pictured early this morning) off the Kent coast, demanding the vessel be moved nearer the shore so they can swim to Britain

'When you have a big fleet, there is a possibility of finding a stowaway. We are doing whatever is possible, but we also need to work with local authorities and whoever works inside the ports to avoid this incident.'

The crew of the Grande Tema, a 770-foot cargo ship on its way to the UK from Nigeria, found four stowaways on board this week and locked them in a cabin.

But they broke out yesterday morning armed with iron bars and brandished them at the crew who had fed and looked after them.

This graphic shows the ship's route to Britain as well as five piracy incidents along the coast of Africa

The crew quickly locked themselves on the ship's bridge and sent out an alert to the coastguard.

The operation lasted around 25 minutes and no-one onboard was hurt. Four men have been arrested under the Immigration Act and the ship taken to the Port of Tilbury, where is arrived just after 4am this morning.

Essex Police said it had secured the vessel and detained four men under the Immigration Act, and no-one on board had been injured.

SBS Special forces (pictured above in a file photo)

The force said: 'The vessel was boarded and secured shortly after 11pm on Friday December 21 and will now be brought safely into dock at the Port of Tilbury.'

It added: 'It followed reports at around 9.15am (on Friday) of concerns for the safety of crew after a number of people were found on board.'

The force said the vessel, in the Thames Estuary, was boarded at around 11pm and will be brought to the Port of Tilbury to dock.

The Grande Tema, an Italian-registered container ship, circled the English Channel after migrant stowaways were found on board and demanded crew move the ship to shore

The ship's operator, Grimaldi Lines, said four stowaways had been found on board and were armed with iron tubes.

They were calling on the crew to navigate closer to the coast. The force said the ship has been secured and no-one had been injured.

The crew of 27 Italian and Filipino personnel are holed up in the control tower, Mr Kyprianou, added: 'They threatened the crew, they picked up what was around like iron tubing,' he said. 'They wanted to get closer to the shore so they could make their way to the UK. It is a quite a tense situation.

This red line shows how the ship is going in circles as the migrants demand that they are taken to Britain's shores and the crew remain in control

'They were found on board four days ago and were locked in a cabin. The crew have been feeding them under international regulations.

'They feared they might break free, which they now have. The crew are now waiting for the police to board the ship.'

He told Sky News: 'We found four stowaways on the vessel. The vessel was coming from Nigeria and was bound to Tilbury and those four stowaways were in the cabin, and today they managed to escape from the cabin and they started threatening the crew, requesting the master of the vessel navigating very close to the coast.

A photo taken off the coast of Margate today. Many container ships put down anchor in the area on their way up the Thames Estuary

'That request was probably because they wanted to jump and reach the British coast.

'The crew reacted and they locked themselves in the bridge of the vessel and so they are safe, we haven't had any injuries.

'The master is in continuous contact with the UK authorities, particularly with the Essex police and the coastguard. We are waiting to see what is going to happen, we expect authorities to intervene.'

Shipping monitoring sites show the position of the vessel just north of the town of Margate

The migrants are on the ship's weather deck trying to negotiate with the captain, it is understood.

The nationality of the men is not known and the captain of the ship is still reportedly in charge.

The 71,543 tonne ship, which is based in the Sicilian city of Palermo, is carrying cars, vans and earth-moving equipment to the UK.

This map shows the journey of the boat on which armed migrants are currently threatening a crew off the English coast

It had been travelling to the huge container port at Tilbury after leaving Lagos, Nigeria on December 10.

It has not made any stops since, leading owners to believe the migrants snuck onboard in Lagos.

Dover-based marine photographer Nigel Scutt was one of the first alerted to what was going on.

'I had calls from two separate sources,' he said. 'One said it was stowaways on board.

'But the other said that stowaways had come out and made their presence known and have taken over areas of the ship or the vessel itself and threatened the crew in the process.

Close-ups of the ship's movements (green) show it repeatedly turning around during the day

'If that is the case then that is piracy. You normally hear of this off the Horn of Africa - not the Thames Estuary.'

Dover Strait Shipping reported just after 11am: 'BREAKING: Piracy in the Thames Estuary... Reports coming in of stowaways aboard Grande Tema threatening the crew. Incident is ongoing.'

The Grande Tema had previously docked in Benin, Ghana, the Ivory Coast and Morocco. It is not known where the stowaways boarded but Mr Scutt added that the ship, which usually transports containers and heavy machinery, had 'plenty of hiding places'.

The number of piracy incidents in the Horn of Africa more than trebled between 2015 and 2017 – up from 16 cases to 54. However, the majority of these involved being boarded by raiding parties.

The increase has led to rising operational costs in rerouting, increasing speed when faced with suspicious boats, and taking out kidnap and ransom insurance.

In 2014, 35 Afghan Sikhs, including 13 children, were found 'screaming and banging' inside a shipping container in Tilbury that had arrived from Belgium.

One man died and the others were treated in hospital for severe dehydration and hypothermia after their 4,000-mile journey.

British Police insist Friday's incident is not being treated as a 'hostage, piracy or terror related incident'.

An Essex Police spokesman said only: 'We continue to deal with a complex incident on board a vessel that is in the Thames Estuary close to the Essex and Kent borders.

'This follows a call relating to the safety of crew on board at around 9am today.

'We have received no reports that anyone had been harmed and don't believe they are at risk.

'We are not currently treating this as either a hostage, piracy or terror-related incident.'

Over the last two days, the ship has moved up through the English Channel, before the incident this morning. It had originally come from Lagos, in Nigeria

The police spokesman added: 'We are working working closely with our partners to resolve this incident as quickly as possible.

'We are not in a position to provide any details about who is on board at this stage.'

The huge ship continues to circle off the Kent coast. Both the Home Office and the Maritime and Coastguard Agency have declined to comment on the incident, saying Essex Police were in charge.