The project for a third trio of British battlecruisers with 343 mm guns was based on the Orion-class battleships. The third ship of the series—HMS Queen Mary—was built as part of the 1910 program. She entered service as part of the 1st Battlecruiser Squadron in 1913 and took part in the Battle of Heligoland Bight in 1914. The ship sank during the Battle of Jutland after her magazines detonated as a result of coming under focused fire from the German ships.