Terrified families fled after a fight broke out in a restaurant on the ship with reports of “blood everywhere”.
P&O Cruises have now confirmed that a clown was not the cause of the trouble that led to two arrests.
Plates and furniture were said to be used as weapons during the chaos in which six people were hurt with some receiving significant bruising and cuts.
There were claims that the trouble was sparked after a passenger dressed up as a clown interrupted a black-tie party held in one of the ship’s 13 restaurants.
A female entertainer working on the Britannia said a clown crashed a black-tie party held in the 16th floor restaurant, sparking anger from other passengers.
ITV’s Good Morning Britain reporter Richard Gaisford was onboard and said staff told him the trouble was caused by the appearance of the clown.
He said: “The buffet area was immediately sealed off as medical teams went to help the injured.
“Staff told me they’d never experienced anything like it and those behind the violence were confined to a cabin for the last day of the cruise, waiting for police here in Southampton.”
But P&O have stated that there was no clown on board and that this has been backed up by ship staff.
“There was no clown on board or involved in this incident”
After the Britannia arrived in Southampton, a man 43, and a woman 41, both from Chigwell, Essex, were arrested on suspicion of assault.
The pair were released from custody on Sunday but remain under investigation.
Hampshire police said: “There was no clown on board or involved in this incident.
“Officers are investigating following reports of a public order incident on board P&O’s Britannia.
“If anyone has any information, including phone footage of the incident, they should call Hampshire Constabulary.”
The Britannia was returning from Bergen, Norway, following a week-long cruise which would have cost the passengers around £1,000.