| Sir David Lockhart-Muir Renton | January 1957 | January 1958 |
| John Clarke George | October 1959 | June 1962 |
| John Wynne William Peyton | June 1962 | October 1964 |
| John Morris, Baron Morris of Aberavon | October 1964 | January 1966 |
| Dr Jeremy William Bray | 1966 | 1967 |
| Reginald Yarnitz Freeson | January 1967 | October 1969 |