Note to self: Now there is an Interesting Modern Asymmetrical Wargaming Scenario if ever there was one

Russia a 'risk' to undersea cables, defence chief warns

http://www.bbc.co.uk/news/uk-42362500

Update: Follow on in the BBC News 03/01/18, Russian "deep sea snipping capability":
http://www.bbc.co.uk/news/world-europe-42543712

The historic US Sub-Spy action [New York Times]:
http://www.nytimes.com/1998/11/08/us/a-tale-of-daring-american-submarine-espionage.html
Note: Also see Blind Man's Bluff

Interesting Naval Site:
https://www.naval-technology.com