| Alan Neil Ramsay Davidson | Director | 1 Aug 2007 | 29 Sept 2010 | British | 74 years |
| Alan Neil Ramsay Davidson | Secretary | 2 Apr 2008 | 29 Sept 2010 | British | - |
| Alistair Robert Mactaggart | Director | 30 Sept 2016 | 7 Sept 2020 | British | 66 years |
| Andrew Bord | Director | 1 Jan 2015 | 30 Sept 2016 | British | 56 years |
| Andrew George Parker | Director | 29 Sept 2010 | 13 Oct 2011 | British | 57 years |
| Arthur James Hutchison | Director | 21 Oct 1992 | 30 Apr 1993 | British | 93 years |
| Arthur James Hutchison | Director | 26 Apr 1993 | 26 Apr 1995 | British | 93 years |
| Balbir Kelly | Secretary | 15 Sept 2000 | 3 Aug 2001 | British | - |
| Christopher Stuart Ashburn | Director | 7 Sept 2020 | 14 Dec 2022 | British | 58 years |
| Elwyn David Williams | Director | 26 Apr 1992 | 21 Oct 1992 | British | 77 years |
| Frances Mary Firmin | Secretary | 2 Nov 2004 | 2 Apr 2008 | British | - |
| Francis David Booth | Director | 11 Dec 1998 | 9 Aug 2002 | British | 73 years |
| Hextalls Company Secretarial Services Limited | Corporate Secretary | 27 Jun 2007 | 27 Aug 2008 | United Kingdom | - |
| Ian Austin Sparks | Director | 1 Mar 2007 | 29 Sept 2010 | British | 65 years |
| Ian Harrop | Secretary | 26 Apr 1992 | 10 Aug 1994 | British | - |
| Jacqueline Elizabeth Fox | Secretary | 9 Jul 2002 | 22 Apr 2003 | British | - |
| James D'arcy Vincent | Director | 20 Jun 2014 | 1 Jan 2015 | British | 60 years |
| James D'arcy Vincent | Director | 7 Sept 2020 | 30 Jul 2021 | British | 60 years |
| John Edward Blay | Director | 1 Oct 1992 | 30 Sept 1996 | British | 85 years |
| John Hilton Berg | Secretary | 27 Aug 1997 | 15 Sept 2000 | British | - |
| John Richard Thomas | Director | 15 Nov 1996 | 31 May 1999 | British | 79 years |
| Jonathan Mark Francis | Director | 3 Jul 1992 | 24 Sept 1996 | British | 74 years |
| Martin Richard Totty | Director | 5 May 2005 | 29 Dec 2006 | British | 70 years |
| Melvyn Harold Measures | Director | 31 Oct 1994 | 11 Dec 1998 | British | 79 years |
| Michael John Logsdon | Director | 27 Mar 2003 | 2 Nov 2004 | British | 67 years |
| Michael John Logsdon | Secretary | 10 Aug 1994 | 27 Aug 1997 | British | - |
| Nicolas Norman Bedford | Director | 11 Jul 2014 | 1 Jan 2015 | British | 67 years |
| Non-destructive Testers Limited | Corporate Director | 6 Aug 2002 | 22 Apr 2003 | United Kingdom | - |
| Norman Stanley Cooper | Director | 26 Apr 1992 | 21 Oct 1992 | British | 87 years |
| Paul Hearty | Director | 7 Apr 1993 | 24 Sept 1996 | British | 81 years |
| Peter John Sharman | Director | 26 Apr 1992 | 15 Nov 1996 | British | 82 years |
| Peter Mark Franklin | Director | 2 May 2014 | 11 Jul 2014 | British | 50 years |
| Peter William Smith | Secretary | 22 Apr 2003 | 2 Nov 2004 | British | - |
| Philip Dick | Director | 21 Oct 1992 | 7 Apr 1993 | British | 73 years |
| Richard John Montague-fuller | Director | 31 Aug 2016 | 7 Sept 2020 | British | 56 years |
| Richard John Shearer | Director | 29 Sept 2010 | 2 May 2014 | British | 62 years |
| Richard Owen Hudson | Director | 27 Mar 2003 | 16 Apr 2003 | British | 74 years |
| Robert Bruce Hayes | Director | 28 Apr 1994 | 11 Dec 1998 | British | 71 years |
| Robert Frank Boyles | Director | 1 Jan 2015 | 31 Aug 2016 | British | 57 years |
| Stephen Robert Manton | Director | 26 Apr 1992 | 31 Jul 1992 | British | 81 years |
| Stephen Sharp | Director | 29 Sept 2010 | 9 Oct 2012 | British | 61 years |
| Stephen William Broughton | Director | 15 Nov 1996 | 30 Sept 2002 | British | 79 years |
| Steven Archibald Wood | Director | 2 Aug 1999 | 31 Oct 2004 | British | 66 years |
| Swagatam Mukerji | Director | 2 Nov 2004 | 30 Mar 2007 | British | 65 years |
| Swagatan Nukerji | Director | 12 Sept 2007 | 15 Sept 2007 | British | 65 years |
| Timothy Andrew Ablett | Director | 11 Dec 1998 | 2 Aug 1999 | British | 77 years |
| Timothy Andrew Ablett | Director | 22 Apr 2003 | 30 Mar 2007 | British | 77 years |
| Timothy Andrew Ablett | Director | 12 Sept 2007 | 28 Sept 2007 | British | 77 years |
| Vanessa Jones | Secretary | 3 Aug 2001 | 26 Apr 2002 | British | - |