These cables have been tapped and monitored for decades. The only way to secure the information that traverses them is to encrypt the data itself.

Russian submarines have dramatically stepped up activity around undersea data cables in the North Atlantic.

US Navy Admiral Andrew Lennon, the commander of NATO’s submarine forces, said Russian activity has reached a level unprecedented in modern times.

Fears have been raised Russia could covertly deploy submarines to sever communications cables spanning the world.

‘We are now seeing Russian underwater activity in the vicinity of undersea cables that I don’t believe we have ever seen,’ said Admiral Lennon.