Eyewitnesses reported plates and furniture being used as weapons following a black-tie soiree on P&O’s Britannia during a week-long Norwegian fjords cruise, the BBC reports.
Officers from Hampshire Police met the ship on arrival in Southampton and arrested a man and a woman from Essex on suspicion of assault. They have since been released under investigation.
Both the police and P&O, meanwhile, has played down suggestions the unrest was caused by a guest dressed as a clown crashing the black-tie event.
"There was no clown on board or involved in this incident,” said Hampshire Police in a statement. "Officers are investigating following reports of a public order incident on board P&O’s Britannia.”
P&O added: "Following an incident onboard Britannia on Thursday evening, we can confirm that all guests have now disembarked and the matter is now in the hands of the local police."
Good Morning Britain reporter Richard Gaisford, who was onboard the ship, said the trouble in the event followed a “patriotic” afternoon party during which “large amounts of alcohol was consumed”.
Video footage shows hundreds of guests crowded around the deck pool singing and waving Union Jacks.
Anyone with information or footage of the incident is asked to call the force on 101 quoting reference 44190262605.