 HMS Vanguard was a British fast battleship built during World War II and commissioned after the war . She was the only ship of her class and was the biggest , fastest and last of the Royal Navy 's battleships and the final battleship to be launched in the world . Work on the ship 's design commenced before the war because the Royal Navy anticipated being outnumbered by the combined German and Japanese battleships in the early 1940s . The British had enough 15 @-@ inch ( 380 mm ) guns and turrets in storage to allow one ship of a modified Lion @-@ class battleship design to be completed faster than the ships of that class that had already been laid down . Work on Vanguard was started and stopped several times during the war and even after construction had begun , her design was revised several times to reflect war experience . These stoppages and changes prevented her from being completed during the war . 
