300 million cubic miles of ocean. Stealthy, and deadly, the nuclear submarines of the Royal Navy lie in wait in the depths of the world's oceans, ready to listen, intercept, and attack wherever they may be needed - from the coastline of Libya to the ice caps of the Arctic.If the UK is hit by a devastating nuclear strike, they'll be the last military force standing. 200 million pounds of hardware. Award-winning journalist Danny Danziger has been allowed unprecedented access to the elite crew of one of the UK's attack class submarines, joining them on operations and hearing their stories.Unrestricted, and uncompromising, Sub paints a vivid picture of this fascinating, little-known branch of our armed forces. One incredible hunter-killer. In an increasingly unstable world, these are the people who keep us safe.It is time for the silent service to be heard.