DUTCH police were last night trying to solve the mystery of how a North-East woman fell overboard from a ferry.

The 40-year-old woman, from the Gosforth area of Newcastle, fell over a barrier on the ship's top deck and, watched by her horrified male friend, plunged 60ft into the North Sea.

A search and rescue operation was called off after seven hours amid mounting speculation that the woman, who has not been named, would not be found alive.

Officers from Amsterdam Police were yesterday on board the DFDS vessel, the Queen of Scandinavia, in a bid to find out how she fell.

The accident happened at 2.25am yesterday, about 55 miles off Cromer, in Norfolk. The ship had left North Shields at 5.30pm on Tuesday, bound for the port of Ijmuiden, near Amsterdam, Holland.

A search by a host of rescue craft was called off at 10am.

Roland McKie, watch manager at Yarmouth Coastguard, which co-ordinated the search, said: "Sadly, after seven-and-a-half hours, we were unable to find any signs of the woman.

"The search has now been terminated since it is now well beyond the expected survival time, given the water temperatures."

A spokeswoman for the ferry operator said: "No one could survive more than six hours in the North Sea, even at summer temperatures of about 17 degrees, as it was today."

The 35,000-tonne ship, carrying 800 passengers, began to turn as soon as the alarm was raised, but took about 15 minutes to slow from its speed of 20 knots and return to the spot where the woman disappeared.

A marker buoy was dropped straight after the woman fell, and a lifeboat was launched from the ferry within five minutes. Rescuers later spotted the buoy, but the woman was not found.

The search and rescue operation included an RAF helicopter and four boats, the Queen of Scandinavia's rescue craft, and the Rassay, which services the nearby Viking Field of gas platforms, along with its rescue ship.

The ferry had been due to dock at Ijmuiden at 3pm yesterday, but was expected to arrive at 9.30pm last night. It will return to Tyneside later today.

Norfolk Police were liaising with Northumbria Police last night to trace the woman's relatives.

Hans De Vreugd, of the Dutch Maritime Police, said: "The investigation is still running and we don't know anything yet.

"We are talking to the ship's crew and should have a clearer picture soon."