Hermes was the first British aircraft carrier designed as a carrier from the keel, rather than rebuilt from another kind of ship. Armstrong Whitworth laid her down at Walker on the Tyne on 15 January 1918 and launched her on 11 September 1919. Completion waited on what the Navy learned from Eagle and Argus. She was commissioned on 19 February 1924.
She spent most of her life east of Suez. In 1942 she was with the Eastern Fleet. Her Swordfish were ashore. On 8 April she left Trincomalee with the Australian destroyer Vampire, ahead of a Japanese raid on the port. Richard F. J. Onslow was her captain.
On the morning of 9 April a floatplane from the battleship Haruna found them off Batticaloa. They turned back toward the port. Carrier aircraft from Vice Admiral Chuichi Nagumo's force hit Hermes more than forty times. She had no aircraft of her own to send up. She sank before noon. Three hundred seven of her crew were killed, Onslow among them. Vampire was sunk the same morning. The bombs are not credited to one Japanese ship.
Hospital ship Vita took off about six hundred survivors. The wreck lies off the east coast of Ceylon.