A cruise ship at the centre of a vomiting bug scare was due to arrive in Belfast at the start of next month.

But the vessel will now cut short its voyage in the Scottish port where it is berthed, its operators said last night.

Hundreds of passengers and crew on the Marco Polo, which is in Invergordon, Easter Ross, have shown symptoms of norovirus and are being treated on board.

Five others have been treated in hospital after falling ill on the ship, which had been due to arrive in Belfast next month, while a sixth person was airlifted to hospital after developing a medical condition unrelated to the suspected norovirus outbreak.

Passenger Roy Sillett (74), a retired man from Norwich, died yesterday of an apparent heart attack said to be unrelated to the bug.

The ship's operator, Transocean Tours of Bremen, said the decision for the ship to terminate its 10-night cruise four days into the trip was taken in consultation with NHS Highland.

A spokeswoman said arrangements will be made for all passengers who are fit to travel to disembark and go home at the “earliest opportunity” but she could not say how soon that might be.

Those passengers who doctors think should not travel will remain on board for continued nursing and will be sent home once fully recovered.

The Marco Polo left Tilbury in Essex on Saturday on a round-Britain cruise.

About 380 people on board the ship are showing symptoms of the illness, NHS Highland said.

The health board is awaiting results of tests to confirm whether the bug is the norovirus.

Four people are still receiving hospital treatment in Inverness while one other has been allowed to return to the boat.

Those taken unwell on the ship were being treated by a team of GPs and local nurses.

Of the 380 people showing symptoms, 340 were passengers and 40 were crew members,

There are 769 passengers and 340 crew on board and those not showing symptoms were allowed to go ashore yesterday after port health officials inspected the ship.

Transocean Tours said the man who died suffered a fatal heart attack on board the ship yesterday.

NHS Highland said Mr Sillett had serious underlying health problems and a post-mortem examination would be carried out to establish the exact cause of his death.

Locals have questioned why passengers were allowed to go ashore yesterday.

Cromarty Firth SNP councillor Maxine Smith said: “They have been allowed to go into local cafes and shops when apparently this virus is spread by touch.

“This is really concerning.”

Nicole Bebbington (28), from Invergordon, said she was worried about her two children, aged three and eight: “I hope they have taken the proper precautions, but if people have been let off the boat, then that is worrying.

“I'm not so worried for myself but for my kids. I wouldn't want them at risk.”

Reports yesterday suggested passengers on the Marco Polo's previous trip, who disembarked on Saturday, were also struck with a sickness bug.

Transocean said the Marco Polo was given a clean bill of health on returning from its previous cruise in Iceland and while a very small number of people on board suffered symptoms of gastroenteritis during the cruise, this was unrelated to the current outbreak.

The norovirus is also called the “winter vomiting disease” because people usually get it during the winter months, but it can occur at any time of the year.

It spreads very easily from person to person and can survive for several days in a contaminated area.

The bug can also spread through contact with surfaces or objects that are contaminated, or by eating contaminated food or water.