They abandoned the 2,400-tonne Liberian-flagged MS Explorer after getting into difficulties near the South Shetland Islands, south of Argentina, after a small hole was punched in the hull during the early hours.

After enduring air temperatures of minus 5C and sea temperatures of 1C, the passengers and 54-strong crew were eventually transferred, uninjured, to Norwegian cruise ship the NordNorge, which had gone to their rescue.

Fourteen of the Britons were clients of adventure holiday company Explore which has its headquarters at Farnborough, Hampshire.

They were taking part in Explore's Spirit of Shackleton tour lasting 25 days, starting from the port of Ushuaia on the southern tip of Argentina and including the Falkland Islands and South Georgia.

Passengers abandoned the vessel near a huge iceberg, in a vast expanse of freezing polar water.

They wore red life-jackets as they boarded shallow, rigid-hulled lifeboats before transferring to rescue vessels..

The Explorer listed to one side at about 25 degrees when passengers took to the lifeboats but later slipped further towards the sea lying at 45 degrees, with the deck almost in the water.

The rescue operation was being run from the United States although coastguards at Falmouth, in Cornwall, were also involved because cruise liners can lodge search and rescue plans with them.

The British Maritime and Coastguard Agency (MCA), was informed of the accident at just before 6am.

Andy Cattrell, watch manager from Falmouth Coastguard, said they had good communication links in the area and were passing information to America for coordinators there to pass on to Argentina.

Four US vessels only 90 minutes away were expected to help with the rescue, and the operation was being coordinated from the US Naval Base at Norfolk, Virginia.

Mr Cattrell said there had seemed to be quite an orderly abandonment of the ship.

Explore's managing director Ashley Toft said: "While such incidents are very rare, they are nevertheless shocking when they occur."

Soon after picking up the passengers from the lifeboats, Arnvid Hansen, the captain of the NordNorge, operated by Norwegian cruise company Hurtigruten, said they were cold but not suffering from hypothermia.

"It was no problem to get them on board.

"They were picked up from the lifeboats...and this operation took around one hour.

"The passengers are in our premier lounge having warm food and drying their clothes on board. Some are cold but none has hypothermia. We are giving them as many clothes as we can."

Last night the vessel was heading for King George Island, Antarctica, where the passengers were expected to be taken off.

The Explorer's owner G.A.P. Adventures, based in Toronto, said the vessel "hit ice" in the Bransfield Strait off King George Island, at 5.24am UK time.

It added that all passengers and crew were safe and uninjured.

The company went on: "Standard procedures were followed by the crew with passengers calmly evacuated to the ship's life rafts and then transferred to the NordNorge, which was in the area."

Doubts raised over vessel's safety and suitability

FEARS over safety of the MS Explorer and the suitability of such vessels for cruises in Antarctic waters emerged as the rescue operation was underway yesterday.

UK Maritime and Coastguard Agency (MCA) inspectors had found five faults with the vessel when it docked at Greenock in Scotland in May this year.

They included missing search and rescue plans and lifeboat maintenance problems. Watertight doors were described as "not as required", and the fire safety measures were also criticised.

Maritime and Coastguard Agency spokesman Mark Clark said: "These were not huge problems and were all rectified before the vessel sailed. It would not have been allowed to depart if everything had not been sorted out."

It is understood that Chilean port state control inspectors also found six deficiencies during an inspection in Puerto Natales in March, including two related to safety of navigation matters.

The MCA also said that classification society Det Norske Veritas issued a passenger safety certificate for the vessel on October 21.

But a UK maritime expert said yesterday: "Passengers had to wait in cold conditions in old-style open lifeboats.

"The vessel was not breaking any rules by having such lifeboats rather than the more-closed newer ones. But you have to question whether a vessel visiting icy waters with elderly passengers aboard was as equipped as it might have been."

Mark Dickinson, assistant general secretary of maritime union Nautilus UK, said: "The growing trend to run cruises in increasingly exotic and remote locations, often in inherently dangerous conditions, is an issue of increasing concern.

"There are many questions about the suitability of some ships to operate in such potentially-adverse conditions, often well away from adequate search-and-rescue cover."

The union said that such issues needed to be addressed as part of a broader review of cruise ship safety, and added that it had already raised its concerns through the International Federation of Shipmasters' Associations.

Explorer pioneered South Atlantic tours

THE MS Explorer is one of the best-known specialist cruise ships in the world and is built to withstand the type of conditions it would meet in Antarctic waters.

It pioneered the market for Antarctic tours, which also take in South Atlantic highlights such as the Falkland Islands and South Georgia, with holidaymakers typically paying anything from £4,500 per person for an eight-night trip that includes flights to and from Buenos Aires, and then connecting flights to the port of Ushuaia on the tip of Argentina.

From there they are able to take the shortest sea-crossing, taking about 35 hours.

The stricken Explorer was on a 25-day super trip round the Falklands, South Georgia and Antarctica and had sold packages in Britain at prices starting at £7,250.

It visited the Falklands last weekend when many passengers had disembarked to visit the penguin colonies.

The Liberian-flagged 2,400-tonne vessel is designed to withstand Antarctic conditions and is thought to have starting sinking during its latest cruise after hitting something "significant".

Maritime and Coastguard Agency spokesman Mark Clark said: "There was a lot of ice in the area, but the vessel was built to withstand ice."

The vessel is owned by Toronto-based G.A.P Adventures.

One of the British tour companies offering holidays on the Explorer is Noble Caledonia , of London, but it did not have anyone booked on this trip.