| GEOGHEGAN, Nicole Ann ACTIVE | Secretary | 29 Nov 2024 | | | | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| MORRIS, Paul Anthony ACTIVE | Director | 12 Jun 2026 | | United Kingdom | April 1974 | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| TAYLOR, Susannah Natalie ACTIVE | Director | 12 Jun 2026 | | United Kingdom | July 1975 | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| WILLIS, Helen Margaret ACTIVE | Director | 31 Mar 2024 | | United Kingdom | January 1964 | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| FRANKS, Clive Leonard RESIGNED | Secretary | 30 Apr 1998 | 31 May 2011 | | | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB, United Kingdom |
| RACE, Brian William RESIGNED | Secretary | | 30 Apr 1998 | | | 53 Clarendon Way, Chislehurst, Kent, BR7 6RG |
| SEYMOUR, Charmaine Alex RESIGNED | Secretary | 01 Sep 2006 | 18 May 2012 | | | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB, United Kingdom |
| SINGLETERRY, Maria RESIGNED | Secretary | 01 Sep 2020 | 29 Nov 2024 | | | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| STARKEY, Paul Michael RESIGNED | Secretary | 03 Sep 2012 | 20 May 2013 | | | Costain House, Vanwell Business Park, Maidenhead, Berkshire, SL6 4UB |
| WOOD, Tracey Alison RESIGNED | Secretary | 01 Jun 2011 | 01 Sep 2020 | | | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB, United Kingdom |
| ARMITT, John Alexander RESIGNED | Director | 09 Apr 1997 | 30 Jun 2001 | | February 1946 | The Manor House, The Lee, Great Missenden, Buckinghamshire, HP16 9NA |
| BICKERSTAFF, Anthony Oliver RESIGNED | Director | 05 Jun 2006 | 30 Nov 2020 | England | June 1964 | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB |
| BOWEN, Timothy Garnet RESIGNED | Director | 21 Oct 2013 | 31 Aug 2017 | United Kingdom | September 1969 | Costain House, Vanwell Business Park, Maidenhead, Berkshire, SL6 4UB |
| BURDES, Martin Fulton RESIGNED | Director | | 31 Aug 2013 | England | March 1953 | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB |
| CAMPBELL, John Richmond RESIGNED | Director | 29 Jan 1997 | 02 Jun 2000 | | July 1944 | 2 Sutton Avenue, Slough, Berkshire, SL3 7AW |
| CLEMENTS, Warren John RESIGNED | Director | 18 Mar 2022 | 31 Mar 2024 | United Kingdom | August 1972 | Costain House, Vanwell Business Park, Maidenhead, Berkshire, SL6 4UB |
| COSTAIN, Peter John RESIGNED | Director | | 14 Feb 1994 | England | April 1938 | Heronden Smallhythe Road, Tenterden, Kent, TN30 7LN |
| DOUGHTY, Stuart John RESIGNED | Director | 01 Jul 2001 | 12 Sep 2005 | United Kingdom | September 1943 | Bradley Farm House, Kinlet, Bewdley, Worcestershire, DY12 3BU |
| FLEMING, Lucy Jane RESIGNED | Director | 30 Nov 2020 | 12 Jun 2026 | England | July 1976 | Seventh Floor, 70 St Mary Axe, London, EC3A 8BE, United Kingdom |
| HILL, Peter John RESIGNED | Director | | 12 Oct 1994 | | August 1952 | Flat2, 2 Eaton Place, London, SW1X 8AD |
| HUNTER, Martin David RESIGNED | Director | 07 May 2019 | 18 Mar 2022 | England | March 1959 | Costain House, Vanwell Business Park, Maidenhead, Berkshire, SL6 4UB |
| LOVELL, Alan Charles RESIGNED | Director | 01 Feb 1994 | 08 Apr 1997 | England | November 1953 | The Palace House, Bishops Lane, Bishops Waltham, Hampshire, SO32 1DP |
| MCCOLE, Charles Joseph RESIGNED | Director | 26 Apr 2002 | 04 Jun 2006 | England | September 1952 | Chimneys, 9 Woodcote Place, Ascot, Berkshire, SL5 7JT |
| ROBERTS, Miles William RESIGNED | Director | 28 Mar 2001 | 31 Dec 2001 | | February 1964 | 2 Grafton Place, Standon, Hertfordshire, SG11 1LT |
| VAUGHAN, Alexander John RESIGNED | Director | 31 Aug 2013 | 21 Oct 2013 | England | December 1969 | Costain House, Vanwell Business Park, Maidenhead, Berkshire, SL6 4UB |
| WYLLIE, Andrew RESIGNED | Director | 12 Sep 2005 | 07 May 2019 | England | December 1962 | Costain House, Vanwall Business Park, Maidenhead, Berkshire, SL6 4UB |