Four stowaways who reportedly threatened the crew of a cargo ship coming from Nigeria with iron bars were held on Saturday after British police boarded the vessel and arrested them.
The Grande Tema, a 71,000-tonne ship which set off from Lagos on December 10, was boarded and secured by police and brought into its destination port of Tilbury in Essex, east of London.
"Four men have been detained under the Immigration Act," Essex Police said.
The police intervention followed reports of concerns for the safety of crew after a number of people were found on board.
"No one on board the vessel has been injured," police said.
Paul Kyprianou, a spokesman for the ship's owner Grimaldi Lines, said the four stowaways were discovered after the vessel set sail from Lagos.
They had been detained but managed to free themselves on Friday and the 27 crew members locked themselves on the bridge, he said.
"They have been threatening the crew" with iron tubes, said Kyprianou. They wanted the ship to be directed closer to the British coast.