The class took part in the July 1914 test mobilisation and deployed to Scapa Flow as the crisis became war. As the Royal Navy's first 13.5-inch dreadnoughts, the Orions were core units in developing British battle doctrine rather than peripheral older ships. The decisive-battle plan concentrated the Grand Fleet to overwhelm the High Seas Fleet. Its weakness was political and operational because Germany did not have to sail and fight unless its commanders believed the circumstances favoured them.
Chapter · 35:55-37:00
Grand Fleet doctrine and war mobilisation
By 1914 the Orions were core battle-fleet units, although hopes for decisive action assumed Germany's High Seas Fleet would offer the battle Britain wanted.