An investigation into the mysterious sinking of a fishing boat off the North-East coast is continuing.

The Marine Accident Investigation Branch, part of the Maritime Coastguard Agency in Southampton, is carrying out an inquiry into how the Norwood came to sink close to Hartlepool Marina at the start of December.

Two experienced fishermen had to be plucked from icy waters by passing fishermen after spending up to 45 minutes struggling for their lives in the pitch darkness.

Martyn Pellew, group development director of PD Ports plc, said: "The investigation by the Marine Accident Investigation Branch is on-going and has not yet reached a resolution."

Skipper Stephen Horsley, 50, and fishermen Paul Slimmings, 37, said they had no idea what had happened to their boat, Norwood, but said it sank in seconds at about 5.30pm on Tuesday, December 6.

They each said they felt lucky to be alive, and believed they had only survived due to the courage and determination of the fishermen who came to their rescue.

Mr Horsley, from Hartlepool's Headland, said: "I would say I was seconds away from death, not minutes, when the fishing crews arrived. Without doubt, I owe my life to them. I want them to know how appreciative I am. They saved my life."

Mr Horsley suffered chest injuries in the incident and was barely conscious when he was plucked from the water by Hartlepool lifeboat crews.

He spent four days in hospital. Mr Slimmings, also from the Headland, suffered shock and hypothermia, but was released after treatment.

Soon after the sinking, the vessel was salvaged and taken into Hartlepool dock to prevent if from obstructing other boats heading into the harbour.