The Deputy First Sea Lord (D.F.S.L.) was a senior Royal Navy flag officer on the Board of Admiralty of the Royal Navy.[1]
| Office of the Deputy First Sea Lord | |
|---|---|
 Ensign of the Royal Navy | |
| Department of the Admiralty | |
| Member of | Board of Admiralty |
| Reports to | First Sea Lord |
| Nominator | First Lord of the Admiralty |
| Appointer | Prime Minister Subject to formal approval by the King-in-Council |
| Term length | 1-4 years |
| Inaugural holder | Rosslyn E. Wemyss |
| Formation | 1917-1919, 1942-1946 |
- ^ Marder, Arthur J. (Mar 31, 2014). From the Dreadnought to Scapa Flow: Volume IV 1917, Year of Crisis. Seaforth Publishing. p. 223. ISBN 9781848322011.