A British woman is believed to have fallen overboard from a cruise ship in the Mediterranean.

The passenger was reported missing on the Aurora ship as it sailed from the Portuguese city Oporto to Barcelona, said P&O Cruises.

The ship's crew were alerted and ordered an immediate search of the area for the as-yet unnamed woman.

A spokeswoman for P&O Cruises later said authorities were believed to have called off the search for the woman, who remains missing. She confirmed the passenger had fallen overboard from the ship and that next of kin had been informed.

The Aurora left Southampton for a 14-night western Mediterranean cruise on September 26. P&O Cruises confirmed all passengers on board were British.

Passengers on the Aurora expressed their shock.

Pat Rodgers, 70, from Sheffield, said the missing woman was believed to be in her 70s and on holiday with her daughter. Mrs Rodgers said the water had been "very choppy" and people on board were "sad and subdued" as a major air and sea search operation took place.

She said: "The captain made an announcement over the loudspeaker at 8.10am this morning and asked everyone to help keep a lookout. There have been planes and a helicopter circling overhead and the lifeboats are out. The helicopter has gone back to Lisbon now to refuel. We can see other cruise ships and cargo ships all helping with the search.

"We heard that the woman is 72 and was on holiday with her daughter but we don't know how she fell in. The passengers are all very sad and subdued as the outlook doesn't look good. The sea is very choppy. We are just so concerned for this woman and her family. It is awful."

She added: "The crew have been great. They are keeping things calm and the captain is giving frequent updates."