His Majesty's Hospital Ship (HMHS) Britannic sunk in 55 minutes on 21 November 1916. It was larger than the Titanic but went down faster as the engines were accelerated in an attempt to beach it.

In the wake of the Titanic disaster, Britannic was re-engineered to be even stronger. And yet she sank in just 55 minutes - three times faster than Titanic. It's one of Britain's greatest untold ...