The sub was relaying images from 300ft down to an oil rig maintenance crew 120 miles off Aberdeen.
The man-eater flashed across the screen for just an instant before disappearing into the dark.
A fellow worker on the rig said: "The controller of the sub got the fright of his life.
"He was quietly going about his job when this monster came out of nowhere, swam across the camera and then was gone into the dark. He tried to follow it but it disappeared."
Shark expert Doug Herdson of the National Marine Aquarium in Plymouth said last night: "This is an important sighting. We can't be 100 per cent sure but it looks like a Great White.
"There's no reason why it couldn't have travelled here from the coast of the US.
"There's plenty of food in the North Sea and the temperatures are fine for them. Sharks are attracted to rigs because the water near the structure is warmer.
"If there was going to be a Great White in the North Sea, it would be likely to be found near a rig."
A worker on the platform said: "Ex-fisherman on the rig are convinced this is a Great White - no one would dare go in the water."
The Great White - the man-eater of the Jaws horror movies - might have been attracted by the hordes of fish and sea mammals which live around the rig, experts believe. Whales, sea lions, porpoises and seals have been spotted - all staples of a Great White's diet.
A tech expert on the rig said: "The sea is warmer around the platforms because we extract oil at a very high temperature."
The scary footage was taken below the Kittiwake oil platform by an unmanned sub called a ROV Triton XLS. It was carrying out inspection work on anchor points connected to the massive structure.
Last summer, The Sun published a series of pictures showing what is believed to have been a Great White off the Cornish coast.
And in January, a mutilated seal was washed up on a beach in Norfolk on the east coast of England, which experts believed had been chomped by a huge shark.
The Great White can grow to more than 20ft long and weigh over two tons.
It is normally found off Australia, South Africa and America.
© 2008 - The Sun