A passenger dressed as a clown has reportedly sparked a massive brawl aboard a P&O cruise leaving "blood everywhere".

The huge fight started on the P&O Britannia cruise ship with families fleeing from the raucous as passengers reportedly used plates and furniture weapons.

Emergency services rushed to the ship's 16th-floor restaurant at 2am on Friday morning.

Paramedics were on the scene tending to injured staff who attempted to stop the brawl that erupted between passengers.

Travellers reportedly smashed plates and beat each other with furniture and there was "blood everywhere", a witness reported.

The fight broke out during a "patriotic" black-tie event on board the cruise ship on Thursday evening with "large amounts of alcohol being consumed", according to reporter Richard Gaisford said on Twitter.

According to a witness at the scene, passengers were upset when a guest dressed up as a clown despite a no fancy dress code.

The scuffle turned violent after guests began pelting objects at each other, with members of staff frantically trying to stop the chaos.

The ship reached its final leg of a week-long cruise to Norway's fjords and was travelling back to Southampton port when the incident happened.

GMTV's chief correspondent Richard Gaisford tweeted: "'There was blood everywhere.' Violent late-night brawl in the buffet onboard P&O cruises Britannia left staff who intervened injured, as passengers used furniture and plates as weapons. Witnesses told me they were so frightened they had to hide, as family groups fought.

"The violence occurred on the final leg of a week-long cruise to Norway’s fjords.

"I became aware of trouble when officers made an emergency tannoy [announcement] at 2am for security staff to rush to the 16th-floor restaurant.

"I went too and found passengers shocked by what they’d seen."

Another passenger said: "I was in my room when the security tannoy happened at 2am.

"I saw two people being escorted out by police - police holding their belongings - limping.

"Just to clarify, the majority of those onboard were perfectly civilised and nice individuals. It was just ruined by a few drunk idiots."

The buffet area was closed and medical teams tended to injured staff and those who started the fight were sectioned off in their respective cabins.

The ship arrived back to its homeport in Southampton this morning and will depart on a Mediterranean cruise later today.

A P&O Cruises spokesman said: “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. We do not tolerate disruptive behaviour”