11. IOR/R/20/B/2680-2683 Reference (shelfmark): IOR/R/20/B/2680-2683 Title: Chief Secretary: Temporary secret files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1951-1958 Extent: 4 files
12. IOR/R/20/B/3383-3444 Reference (shelfmark): IOR/R/20/B/3383-3444 Title: Chief Secretary: Secret Annexe files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1958-1965 Extent: 62 files
13. IOR/R/20/B/1061-1608 Reference (shelfmark): IOR/R/20/B/1061-1608 Title: Civil Secretary: Confidential and Secret Files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1938-1940 Extent: 548 files
14. IOR/R/20/B/1609-1677 Reference (shelfmark): IOR/R/20/B/1609-1677 Title: Civil Secretary: Confidential (annual series) files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1938-1951 Extent: 69 files
15. IOR/R/20/B/1678-1994 Reference (shelfmark): IOR/R/20/B/1678-1994 Title: Civil Secretary: World War II Ordinary files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1939-1942 Extent: 317 files
16. IOR/R/20/B/2377-2653 Reference (shelfmark): IOR/R/20/B/2377-2653 Title: Chief Secretary: Secret and Top Secret files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1941-1952 Extent: 267 files
17. IOR/R/20/B/1995-1999 Reference (shelfmark): IOR/R/20/B/1995-1999 Title: Civil Secretary: World War II Secret and Confidential files Collection Area: India Office Records and Private Papers Languages: English Date Range: 1939-1940 Extent: 5 files
18. IOR/R/20/B/2684-2780 Reference (shelfmark): IOR/R/20/B/2684-2780 Title: Chief Secretary: Ordinary files relating to the Eastern Aden Protecorate, Western Aden Protectorate and Kamaran Collection Area: India Office Records and Private Papers Languages: English Date Range: 1957-1964 Extent: 96 files
19. IOR/R/20/B/2534 Reference (shelfmark): IOR/R/20/B/2534 Title: Intelligence: Collection Area: India Office Records and Private Papers Languages: English Date Range: Unspecified Extent: 1 file
20. IOR/R/20/B/2535 Reference (shelfmark): IOR/R/20/B/2535 Title: Intelligence: Collection Area: India Office Records and Private Papers Languages: English Date Range: Unspecified Extent: 1 file