| DEMPSEY, John Alistair ACTIVE | Secretary | 31 Aug 2017 | | | | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| MCALPINE, Cullum ACTIVE | Director | 01 Oct 1993 | | England | January 1947 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| MCALPINE, Hector George ACTIVE | Director | 30 Sep 2025 | | United Kingdom | May 1980 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| MCALPINE, Olivia Alice Gemma ACTIVE | Director | 30 Sep 2025 | | United Kingdom | October 1986 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| WOTHERSPOON, Robert John William ACTIVE | Director | 31 Oct 2018 | | England | January 1967 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| COWEN, Brendon Raymond RESIGNED | Secretary | 01 Jul 1995 | 30 Nov 2005 | | | 92 Eastmoor Park, Harpenden, Hertfordshire, AL5 1BP |
| PEARSON, Kevin John RESIGNED | Secretary | 26 Jun 2013 | 28 Apr 2025 | | | Eaton Court, Maylands Avenue, Hemel Hempstead, Hertfordshire, HP2 7TR, United Kingdom |
| PRAIN, Graham Lindsay RESIGNED | Secretary | | 01 Jul 1995 | | | Waverley, Granville Road, St Georges Hill, Weybridge, Surrey, KT13 0QJ |
| SHELLEY, Miles Colin RESIGNED | Secretary | 19 Dec 2000 | 31 Aug 2017 | | | Eaton Court, Maylands Avenue, Hemel Hempstead, Hertfordshire, HP2 7TR |
| WALKER, Robert Peter RESIGNED | Secretary | 30 Nov 2005 | 26 Jun 2013 | | | Eaton Court, Maylands Avenue, Hemel Hempstead, Hertfordshire, HP2 7TR |
| BUDDEN, Derek Ernest Arthur RESIGNED | Director | 01 Jan 1995 | 31 Oct 1999 | | September 1932 | Elmfield 25 Batchworth Lane, Northwood, Middlesex, HA6 3DU |
| GREENBOROUGH, John Hedley, Sir RESIGNED | Director | | 26 May 1994 | | July 1922 | 30 Burghley House, London, SW19 5JB |
| GROVER, George Clifford RESIGNED | Director | 01 Dec 1992 | 31 Jul 2000 | | December 1926 | 321 Lauderdale Tower, London, EC2Y 8NA |
| HARDING, Christopher George Francis, Sir RESIGNED | Director | 01 Dec 1992 | 13 Dec 1999 | | October 1939 | 7 Rutland Street, London, SW7 1EJ |
| JENKINS, David Stannard RESIGNED | Director | 17 Dec 2015 | 31 Dec 2023 | United Kingdsom | April 1944 | Eaton Court, Maylands Avenue, Hemel Hempstead Industrial Estate, Hemel Hempstead, Hertfordshire, HP2 7TR |
| JOYCE, Donald Crawford RESIGNED | Director | 17 Dec 2015 | 04 Oct 2019 | United Kingdom | November 1973 | Renewable Energy Systems Ltd, Beaufort Court, Egg Farm Lane, Kings Langley, Hertfordshire, WD4 8LR, United Kingdom |
| MCALPINE, Alistair, Lord RESIGNED | Director | | 03 Apr 1995 | | May 1942 | 40 Bernard Street, London, WC1N 1LG |
| MCALPINE, Andrew William, Sir RESIGNED | Director | 17 Dec 2015 | 30 Sep 2025 | United Kingdom | November 1960 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| MCALPINE, David Malcolm, The Hon RESIGNED | Director | 01 Oct 1993 | 30 Sep 2025 | United Kingdom | October 1946 | Concept House, Home Park Mill Link, Kings Langley, Hertfordshire, WD4 8UD, United Kingdom |
| MCALPINE, Gavin Malcolm RESIGNED | Director | 15 Mar 2016 | 31 Dec 2018 | England | May 1976 | Eaton Court, Maylands Avenue, Hemel Hempstead, Hertfordshire, HP2 7TR, United Kingdom |
| MCALPINE, Ian Malcolm RESIGNED | Director | | 17 Dec 2015 | England | April 1942 | 40 Bernard Street, London, WC1N 1LG |
| MCALPINE, Kenneth RESIGNED | Director | | 01 Oct 1993 | | September 1920 | 40 Bernard Street, London, WC1N 1LG |
| MCALPINE, Malcolm Hugh Dees RESIGNED | Director | | 17 May 2011 | United Kingdom | July 1917 | 40 Bernard Street, London, WC1N 1LG |
| MCALPINE, Robin, Sir RESIGNED | Director | | 19 Feb 1993 | | March 1906 | 40 Bernard Street, London, WC1N 1LD |
| MCALPINE, William Hepburn, Sir RESIGNED | Director | | 25 May 2006 | United Kingdom | January 1936 | 40 Bernard Street, London, WC1N 1LG |
| SHELLEY, Miles Colin RESIGNED | Director | 17 Dec 2015 | 31 Oct 2018 | England | May 1961 | Eaton Court, Maylands Avenue, Hemel Hempstead, Hertfordshire, HP2 7TR, United Kingdom |
| TURNBULL, Nigel James Cavers RESIGNED | Director | 11 May 1993 | 31 Dec 1994 | England | May 1943 | 17 Salisbury Avenue, Harpenden, Hertfordshire, AL5 2QF |
| WALKER TAYLOR, Patrick Hugh RESIGNED | Director | 01 Oct 1995 | 30 Jun 2004 | | September 1946 | 15 Upper Hill Rise, Rickmansworth, Hertfordshire, WD3 7NU |