The eighth HMS Vanguard of the British Royal Navy was a St Vincent class battleship, an enhancement of the "Dreadnought" design built by Vickers at Barrow-in-Furness. She was designed and built during the Anglo-German naval race and spent her life in the British Home Fleet.
At the outbreak of World War I, Vanguard joined the First Battle Squadron at Scapa Flow, and fought in the Battle of Jutland as part of the Fourth Battle Squadron. She was a part of the action from beginning to end, but did not suffer any damage or casualties.
Just before midnight on Monday, 9 July 1917 at Scapa Flow Vanguard suffered an explosion, probably caused by an unnoticed stokehold fire heating cordite stored against an adjacent bulkhead in one of the two magazines which served the amidships gun turrets P and Q. She sank almost instantly, killing an estimated 843 men; there were only two survivors. The site is now designated as a controlled site under the Protection of Military Remains Act.
In terms of loss of life, the destruction of the Vanguard remains the most catastrophic accidental explosion in the history of the UK, and one of the worst accidental losses of the Royal Navy.
See HMS Vanguard for other ships of this name.