To Russia, the Yantar is an oceanic research vessel - to others, including the UK, it's a spy ship, and a worry for Britain's defence chiefs. The vessel has long been suspected of secretly mapping out Britain's undersea cables, where more than 90% of our data, including billions of dollars of financial transactions, are transferred.

The U.S. Coast Guard said it detected and tracked a Russian military spy ship just miles off the coast of Hawaii, the latest incident of a Russian vessel or plane operating close to the U.S. The Russian intelligence vessel, Kareliya, was spotted about 15 nautical miles south of Oahu on Oct. 29, the Coast Guard said Thursday.

“As I speak, a Russian spy ship, the Yantar, is on the edge of UK waters, north of Scotland, having entered the UK’s wider waters over the last few weeks. This is a vessel designed for gathering intelligence and mapping our undersea cables," Defence Secretary John Healey said.

The Coast Guard detected a Russian intelligence ship near U.S. waters off Hawaii, prompting a military response and ongoing monitoring of foreign vessel activities.

Sir Richard Dearlove says Russia is prepared to "do almost anything short of open conflict" as it wages "grey warfare" against the UK and others.