One of the last British armoured cruisers, which were also the largest. The secondary armaments were once again turreted, but the armour protection was deficient.

First assigned to the Home Fleet and then to the China Station 1912. In 1913 she became the flagship of First Cruiser Squadron in the Mediterranean. After duty at the Dardanelles, she was sent to the South Atlantic in September 1914 to join Cradock's squadron. However she was later ordered to join Rear Admiral Stoddart's squadron on the east coast of South America (before she managed to join with Cradock), a decision of which Cradock was unaware.

Recalled to home waters, she became the flagship of Rear Admiral Sir Arbuthnot's First Cruiser Squadron. At the Battle of Jutland in 1916 she led her squadron ahead of the battle fleet when she became engaged with the light scouting forces of the German High Seas Fleet. She damaged and brought to a stop SMS Wiesbaden but as she closed to finish off the crippled cruiser, she came within the range of the German battle fleet. Smothered in fire from the battle cruiser SMS Derfflinger and four battleships, and her forward magazine exploded, flashing along the passageways and setting off the others. There were no survivors.