Four stowaways who allegedly threatened the crew of a cargo ship with armed bars were on Friday night detained by police after an operation to secure the vessel was launched off the Kent coast.

The crew of Grande Tema, en route from Lagos in Nigeria to Tilbury in Essex, locked themselves on the bridge after the stowaways they had discovered broke free from a cabin and started to make their demands, reports Telegraph UK.

The men allegedly demanded the crew sail close to the British coast so they could jump off and swim ashore.

The incident came to an end after Royal Navy helicopters were deployed amid reports that elite Special Boast Service commandos had been deployed to carry out the operation.

Essex Police, which oversaw the operation, said: “We have secured a vessel in the Thames Estuary. Four men have been detained under the Immigration Act”.

The vessel was said to have been boarded at around 11pm and would be brought to the Port of Tilbury to dock.