A Midland couple's trip of a lifetime on one of the world's largest ocean liners has turned into a nightmare after they were confined inside the ship because of bad weather as it missed a number of scheduled stops, their son claimed yesterday.

David Ashton said he had received emails and phone calls from his parents Sandra and Peter Ashton, from Coventry, who had joined the Queen Mary 2 in New York and had looked forward to touring the Caribbean before reaching Rio.

A number of passengers on board the luxury liner have threatened a sit-in after the ship was forced to miss three stops on route from Florida to Rio de Janeiro following damage to a propulsion motor.

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Although she still has three of her motors working, the ship can only travel at normal speed and cannot make up for lost time, a spokesman for operator Cunard said.

He added that the passengers who were leaving the ship in Rio - many of whom boarded in the US - had been offered a 50 per cent refund.

But some of the holiday-makers are unhappy with the offer and have threatened to stay on the ship at Rio instead of disembarking.

The missed stops - in Barbados, St Kitts and Salvador, Brazil - mean the ship can dock, as planned, in Rio late on Thursday night. That means the 1,000 passengers due to get on board in Rio can go ahead as planned, the spokesman said.

Mr and Mrs Ashton, who had never taken a cruise before, have been contacting David since they left Florida.

He said: "Everyone is upset at the way they have been treated - like the fact they didn't even tell them until they were out at sea that they wouldn't be going to the Caribbean. It seems sneaky."

Mr Ashton went on: "The weather conditions are pretty harsh and they have been advised not to go out on the deck. They feel trapped.

"You would think for a big company like that reputation would be very important.

"They seem to be neglecting their customers and not thinking about how much they have paid.

"I think everyone on board is holding out for a full refund. It's a Caribbean cruise where they're not going to the Caribbean - it's more like a ferry journey."

The Cunard spokesman said the captain of the liner was "doing his best" to resolve the dispute with passengers over the change in itinerary.

He added: "Because of the lateness of leaving Fort Lauderdale and the necessity of arriving at Rio to pick up these passengers, they had to miss out ports in order to get there on time.

"Most people are quite happy with the compensation offer but a relatively small group are not and they have had a number of meetings with the captain.

"One of the things they have referred to is not leaving their cabins when they get to Rio."

He said that it was too early to tell what Cunard would do if the passengers refused to leave the ship at Rio when she arrives. Meetings with the captain, Commodore Ronald Warwick, would continue, he added.

About 2,500 passengers are on board the ship, which is on a 38-day trip around South America. The ship is scheduled to complete its full journey in Los Angeles on February 22.