| Rt Hon Sidney James Webb | 1929 | 1930 |
| Rt Hon Edward Montagu Cavendish Stanley, Baron Stanley | 16 May 1938 | 16 October 1938 |
| Rt Hon Malcolm John Macdonald | 31 October 1938 | 29 January 1939 |
| Rt Hon Sir Thomas Walker Hobart Inskip | 1939 | 1939 |
| Rt Hon Robert Anthony Eden | 4 September 1939 | 10 May 1940 |
| Rt Hon Sir Thomas Walker Hobart Inskip, Viscount Caldecote | 1940 | 1940 |
| Rt Hon Robert Arthur James Gascoyne-Cecil, Viscount Cranborne | 1940 | 1942 |
| Rt Hon Robert Arthur James Gascoyne-Cecil, Baron Cecil of Essendon | 1943 | 1945 |