The Admiralty extension into Horse Guards Parade was built in three stages between 1888 and 1905. Designed by the firm of Leeming & Leeming of Halifax, it has been described by the architectural historian Pevsner as "Neo-Wren with French touches."
- Bradley; Pevsner. p. 253.
- Bradley, Simon; Pevsner, Nikolaus (2003). London 6: Westminster. New Haven, CT: Yale University Press. ISBN 0300095953.
- Hamilton, C. I. (2011). The Making of the Modern Admiralty: British Naval Policy-Making, 1805-1927. Cambridge: Cambridge University Press. ISBN 9780521765183. (on Amazon.co.uk).
- "War Organisation" (1902). Admiralty Library, Portsmouth. MSS 320.
- Official Procedure and Rules. 1913. Copy in the Greene Papers. National Maritime Museum. GEE/2.