The 48-year-old man, from Cardiff, got into difficulties at the James Egan Layne wreck at Whitsand Bay on Saturday after he disappeared under his boat.

Together with a friend, the man had dived down to free a tangled marker buoy but ran out of air.

Both surfaced in distress but the crew on their dive boat, the Furious, only managed to retrieve one man.

'Thoroughly covered'

Brixham Coastguards said the missing man's son had to watch as emergency services scoured the area.

The alarm was raised and a search was launched involving two lifeboats, Coastguards, police and the rescue helicopter from RNAS Culdrose near Helston, Cornwall.

However, emergency services called off the operation at 1700 BST, although dive boats continued to search the area.

Brixham Coastguard said: "They thoroughly covered the area with the units and looked at tidal information, but sadly found nothing."

The male was a member of a diving club visiting the area, police said.

The James Egan Layne, a US ship torpedoed on her maiden voyage in March 1945, is one of the most dived wrecks in British waters.

She lies on the seabed about 500m from Scylla, a retired Royal Navy warship, which last year became Europe's first artificial diving reef.