Unconfirmed reports claim that a sixth body has been found in the wrecked Costa Concordia as the cruise ship's owners accused the ship's captain of causing the disaster off the Italian coast.

Costa Crociere said "preliminary indications" suggested Captain Francesco Schettino may have been guilty of "significant human error" which resulted in the Costa Concordia running aground, sparking a frantic evacuation operation.

Frogmen are continuing to scour the submerged parts of the luxury vessel for passengers and crew who are yet to be accounted for after discovering two elderly holidaymakers dead near the liner's sunken restaurant on Sunday.

It came as groups of British survivors caught up in Friday night's incident returned home and gave harrowing accounts of their nightmare - with some revealing they believed they would die.

Pier Luigi Foschi, chairman and chief executive of Costa Crociere, will face the media for the first time at two press conferences in Genoa on Monday, as Italian prosecutors continue to question Capt Schettino in custody.

He is reportedly being held on suspicion of multiple manslaughter and abandoning ship.

In a statement issued yesterday, the ship's Italian owner, a subsidiary of Carnival Cruise lines, said: "We are working with investigators to find out precisely what went wrong aboard the Costa Concordia.

"While the investigation is ongoing, preliminary indications are that there may have been significant human error on the part of the ship's Master, Captain Francesco Schettino, which resulted in these grave consequences.

"The route of the vessel appears to have been too close to the shore, and the captain's judgment in handling the emergency appears to have not followed standard Costa procedures."

Capt Schettino, who has commanded the ship since the boat was built in 2006, told Italian television he was not to blame for the maritime disaster, claiming nautical charts did not show the rocks off the tiny island of Giglio, which ripped a 160ft gash in the ship's hull.

The government has confirmed all 23 British passengers and 12 crew members on board the ship were safe and well, with a number already returning to the UK.

Mandy Rodford, 45, who was celebrating her fourth wedding anniversary with husband John, 46, said she thought her "life was over" as the luxury liner sank into the sea.

Speaking after landing at Heathrow yesterday, Mrs Rodford, who had been hesitant about going on the holiday because she does not like water, said: "I just thought my life was gone. I just thought my life was over, getting in that water.

"I thought, if I don't die from the swimming part, I'm going to die from the shock of having to get in it."

Mr Rodford said they first thought something was wrong during dinner when he heard a "crunch" and his drink started sliding along the table.

He said: "Then the lights went out and came back on.

"And then it (the ship) started going the other way, and quite a lot the other way.

"All the plates were coming off the tables and smashing, and it was just like bedlam.

"Everyone was getting the life jackets, but they told us to stay. They said: 'It's all right, it's under control'."

Rose Metcalf, 23, from Wimborne in Dorset, wiped away tears as she revealed she had written a note to her mother in case she did not survive.

She was one of the last people to be rescued by a helicopter after she clambered from Deck Four to Deck Five.

"There was just so much panic so I decided to wait until the water was high enough so I could jump or swim, but I didn't want to be inside," she said.

Phoebe Jones, 20, from Walton-on-Thames in Surrey, was on stage performing a magic show when the ship ran aground.

"The ship went on a huge, huge lean," she said.

"Suddenly there was a blackout and everything from the stage crashed to one side.

"Some people started to panic, but I was fine."

A honeymooning South Korean couple were found alive by emergency workers, and a cabin services director was also rescued despite suffering a suspected broken leg.

In its statement, Costa Crociere also paid tribute to its staff, praising them for acting "bravely and swiftly" to help evacuate 4,200 people from the listing vessel.