The Belgian fishing boat that sank about 20 miles off the Norfolk coast without sending out a mayday message was called the Sonja.

Based in Zeebrugge, it is thought she sank within minutes at about 2pm on Saturday leading to a massive search operation after three survivors were found in life raft by a cruise ship.

Two other crew members were reported as missing and their bodies were found near the sunken boat on Sunday afternoon by a Maritime and Coastguard Helicopter.

Their bodies were flown to Humberside, where the local police attempted to contact their families.

The Sonja, which had the port code Z 19, was built in 1973 and had a 159 gross tonnage and was 30.7m in length and 8m in breadth according to the www.marinetraffic.com website.

Paul Garrod is the chairman of Caister Lifeboat and had seen off a crew on Saturday which found part of the Sonja's floating wreckage.

He said: 'No mayday was sent out. It (the Sonja) would have gone down within minutes.

'The men in the life raft did send up a flare which was seen by the cruise ship.'

After sinking at an estimated time of 2pm the three men in the life raft were rescued by the Pacific Princess at 6.30pm, which alerted the authorities that two other fishermen were missing.

At 7pm the helicopter from Humberside Coastguard was called out and at 8pm it arrived and discovered the Sonja had sunk with no sign of its two missing.

At 8pm Caister and Gorleston lifeboats were called out as part of an extensive search which involved other cruise ships and passing vessels.

Captain Réjane Gyssens, of the Belgian Maritime Rescue and Coordination Centre network, said the bodies of the two men found by the Coastguard helicopter corresponded with the descriptions of them.

The weekend search also involved the Lowestoft lifeboat.

While the independent Hemsby Lifeboat Station crew was not been called into the search its crew were thinking of the dead men and the local lifeboat crews who searched for them.

Dan Hurd, coxswain, said: 'It is awful. Our thoughts are with the men's family.

'We feel for them and the lifeboat crews who did an amazing job.'