First Sea Lord and Chief of the Naval Staff of the United Kingdom
Armed force ranking
The First Sea Lord and Chief of the Naval Staff is a statutory position in the British Armed Forces usually held by a four star admiral. Wikipedia
Deputy: Vice Chief of the Naval Staff (1941–1946); Deputy Chief of the Naval Staff
Member of: Defence Council; Admiralty Board; Chiefs of Staff Committee
Term length: Not fixed (typically 3–4 years)