The Plans Division [1] was the former war preparation and wartime strategic planning arm of the Admiralty Department from 1917 to 1964, The division originally became the main policy advisory and formulating body to the Chief of the Naval Staff.

Admiral Sir John Jellicoe, First Sea Lord and Chief of Naval Staff whose view was that plans and operations as functions should be separate and distinct.

Long-term policy in regards to the composition of all commands, fleets and squadrons were within its responsibility, continual projecting of naval construction programs were also another duty, however the procedures for planning was always in a constant state of modification due to the significance of changes from one aspect of the war at sea to another.

This usually consisted of the day-to-day, even hour-to-hour communiques, reports and assessments regarding the actions and movements of every one of the enemy's assets.

The scale and complexity was enormous in that it had to cover all the oceans and seas of the world, and that it might affect every British and Allied warships and merchantmen at sea this information in turn passed to the division who had to anticipate and plan contingencies for these types of changes.