To lure out and destroy a portion of the Grand Fleet, the High Seas Fleet (Admiral Reinhard Scheer) composed of 16 dreadnoughts, 6 pre-dreadnoughts and supporting ships, departed the Jade Bight early on the morning of 31 May. The fleet sailed in concert with Rear Admiral Franz von Hipper's five battlecruisers. Room 40 at the Admiralty had intercepted and decrypted German radio traffic containing plans of the operation. The Admiralty ordered the Grand Fleet, with 28 dreadnoughts and 9 battlecruisers, to sortie the night before, to cut off and destroy the High Seas Fleet.