It is a relevant question seeing as 20 of us are crammed into a small, dark, oily-smelling tin otherwise known as a submarine ... one of those urgent dive-dive-dive alarms you hear in war films.

Officers and crew aboard a French nuclear submarine have accidentally blown their cover as well as their location and schedule by recording their runs and jogs on a fitness app.

The navy had initially suspected that the Russian military’s Main Directorate of Deep-Sea Research might be behind the sounds, attempting to gather acoustic signatures from the UK’s submarine ...