Rescue teams have given up hope of finding a missing diver alive.
A search involving four lifeboats and a helicopter was launched when the 53-year-old man went missing during a leisure dive off the coast of Seahouses on the North Northumberland coast.
The Maritime and Coastguard Agency said the owners of the dive boat Sovereign 3 called 999 at 11.30am yesterday, reporting that the man had been missing for an hour and they were concerned for his safety.
A spokeswoman for the agency said: "The man was with a dive buddy and he began to surface because he thought he was running out of air. His buddy went to the surface to raise the alarm and the two were separated."
She said the missing man, who was with a party from Nottinghamshire, had been diving at the Somali wreck at the time - a popular site for scuba enthusiasts in the North East.
A spokeswoman for Northumbria Police said the force's marine unit would continue the search today.
Humber Coastguard requested the launch of Craster RNLI Lifeboat, Seahouses RNLI All Weather and Inshore Lifeboats, Boulmer Independent Lifeboat and Rescue 131 Helicopter from RAF Boulmer.
Other dive boats in the area also joined the search, which was scaled down during the afternoon.
Ian Clayton, Seahouses RNLI lifeboat operations manager, said: "The Seahouses Lifeboats continued the search, awaiting a slack period as the tide turned, which may have caused the missing diver to surface. By this time, all real hope of this diver being found alive had gone."
He said the lifeboats stood down their search on the arrival of a police boat and divers.
"This was a truly harrowing incident for all involved. Such incidents are mercifully rare on this coast," he added.
"Our thoughts are with the friends and relatives of the diver at this tragic time. Our crews all worked well together, and everything humanly possible was done to try and locate the missing man, sadly without success."Reuse content