| Dr Lynda Margaret Clark | 11 June 2001 | |
| Rt Hon James Robert Wallace, Baron Wallace of Tankerness | May 2010 | |
| Richard Sanderson Keen, Baron Keen of Elie | 29 May 2015 | 16 September 2020 |
| Keith Douglas Stewart, Baron Stewart of Dirleton | 15 October 2020 | |
| Catherine Anne Smith, Baroness Smith of Cluny | 29 August 2024 |