| SMITH, Graham Richard ACTIVE | Secretary | 15 Oct 2014 | | | | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| LIMA SOLLERO, Alberto ACTIVE | Director | 11 Nov 2025 | | England | September 1981 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| ROOSENSCHOON, Emile ACTIVE | Director | 01 Oct 2025 | | England | February 1984 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| SIDDIQI, Saad Naved ACTIVE | Director | 11 Nov 2025 | | England | September 1978 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| BRICKNELL, David John RESIGNED | Secretary | 02 Feb 1999 | 28 Feb 2001 | | | 6 Regent Road, Birkdale, Southport, Merseyside, PR8 2EB |
| BURGESS, Keith John RESIGNED | Secretary | 31 Dec 1992 | 06 Jan 1994 | | | Little House, 4 Vicarage Road, Egham, Surrey, TW20 9JW |
| CIESIELSKA, Katarzyna Jolanta RESIGNED | Secretary | 07 Mar 2013 | 15 Oct 2014 | | | 100, Rue De Volmerange, Dudelange, Luxembourg |
| CUBITT, Michael Harry RESIGNED | Secretary | 28 Feb 2001 | 22 Oct 2001 | | | 22 Camellia Way, Simons Park, Wokingham, Berkshire, RG41 3NB |
| DE TURRIS, Atillia Gabriella RESIGNED | Secretary | 20 Mar 1996 | 06 Feb 1998 | | | 8 Vineyard Mews, Preston Place, Richmond Upon Thames, Surrey, TW10 6DD |
| DONALD, Keith Malcolm Hamilton RESIGNED | Secretary | 08 Mar 1995 | 30 Nov 1995 | | | 251 Upper Richmond Road, London, SW15 6SW |
| GOULDING, Graham Thomas RESIGNED | Secretary | 12 Jun 1998 | 01 Feb 1999 | | | 126 Auckland Road, London, SE19 2RP |
| GOULDING, Graham Thomas RESIGNED | Secretary | 06 Jan 1994 | 08 Mar 1995 | | | Hill Cottage Northdown Road, Woldingham, Caterham, Surrey, CR3 7BB |
| GOULDING, Graham Thomas RESIGNED | Secretary | | 31 Dec 1992 | | | Hill Cottage Northdown Road, Woldingham, Caterham, Surrey, CR3 7BB |
| MORTIMER, Jonathan RESIGNED | Secretary | 28 Mar 2003 | 05 Mar 2013 | | | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| PARR, Christopher Martin RESIGNED | Secretary | 22 Oct 2001 | 28 Mar 2003 | | | Treetops, Burney Road, Westhumble, Surrey, RH5 6AX |
| PRICHARD, Teresa Joan RESIGNED | Secretary | 06 Feb 1998 | 12 Jun 1998 | | | 4 Bracken Gardens, Barnes, London, SW13 9HW |
| BOWDEN, Adrian Harold Houston RESIGNED | Director | | 02 Jun 1995 | | June 1938 | 33 Grosvenor Square, London, W1X 9LL |
| BURGESS, David RESIGNED | Director | | 01 Jun 1994 | | April 1945 | The Gatehouse Church Farm, Church Gate Burton Upon Stather, Scunthorpe, South Humberside, DN15 9BS |
| BURGESS, Keith John RESIGNED | Director | | 16 Dec 1993 | | July 1954 | Little House, 4 Vicarage Road, Egham, Surrey, TW20 9JW |
| BUTLER, Geoffrey Doy Hopson RESIGNED | Director | | 31 Dec 2010 | England | October 1946 | Home Green Heath House Road, Worplesdon Hill, Woking, Surrey, GU22 0QU |
| CAMPANARO, Leonard Anthony RESIGNED | Director | 02 Feb 1999 | 25 Jul 2000 | | May 1948 | 1704 Olmstead Way East, Camp Hill, Pennsylvania, 17011845, Usa |
| CARTER, Stuart Robert Aitken RESIGNED | Director | | 15 Jul 1994 | | April 1952 | 4 Burwood Avenue, Eastcote, Pinner, Middlesex, HA5 2RZ |
| COOPER, Stephen Richard RESIGNED | Director | 16 Jun 2014 | 01 Oct 2025 | England | December 1966 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| CUBITT, Michael Harry RESIGNED | Director | 20 Mar 1996 | 01 Feb 1999 | | July 1948 | 22 Camellia Way, Simons Park, Wokingham, Berkshire, RG41 3NB |
| DOBSON, Brian RESIGNED | Director | 16 Dec 1993 | 10 Mar 1995 | | February 1934 | The Benches, Redbrook Road, Monmouth, Gwent, NP5 3LZ |
| FAZZOLARI, Salvatore Domenico RESIGNED | Director | 25 Jul 2000 | 23 Feb 2012 | United States | August 1952 | 1827 Red Spruce Lane, Mechanicsburg, Pennsylvania 17050, United States |
| FITZGERALD, Frank, Dr RESIGNED | Director | 01 Jan 1994 | 30 Mar 1995 | | November 1929 | 21 Cartmel Road, Redcar, Cleveland, TS10 4JT |
| GOULDING, Graham Thomas RESIGNED | Director | | 30 Mar 1995 | | June 1949 | Hill Cottage Northdown Road, Woldingham, Caterham, Surrey, CR3 7BB |
| HATHAWAY, Derek Charles RESIGNED | Director | 11 Jan 1999 | 18 Dec 2007 | | May 1944 | 7 Northwatch Lane, Mechanicsburg, Pennsylvania, PA17055, Usa |
| HOAD, Martin Roger Gregory RESIGNED | Director | 10 Dec 2010 | 01 Nov 2011 | United Kingdom | November 1965 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| HOMER, Harold RESIGNED | Director | 18 Apr 2000 | 15 Oct 2002 | | November 1940 | 11 Westover Drive, Burton Upon Stather, Scunthorpe, South Humberside, DN15 9HH |
| KIMMEL, Mark Edward RESIGNED | Director | 01 Nov 2011 | 01 Oct 2012 | Usa | March 1959 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| KNIGHT, Jill, Baroness Knight Of Collingtree RESIGNED | Director | 01 Feb 1999 | 15 Oct 2002 | | July 1927 | Holmwood, Collingtree, Northampton, NN4 0NE |
| LECLERCQ, Herve Michal RESIGNED | Director | 03 Oct 2011 | 16 Dec 2013 | United Kingdom | June 1962 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| LYNN, Andrew Roger RESIGNED | Director | | 01 Sep 1995 | England | February 1949 | 1 Claremont Road, Twickenham, Middlesex, TW1 2QX |
| MANSELL, Kenneth Leslie RESIGNED | Director | 17 Oct 2000 | 15 Oct 2002 | | April 1943 | Caramba Ashdown Place, Forest Row, East Sussex, RH18 5LP |
| MELLODEY, Martin John RESIGNED | Director | | 21 Sep 1994 | | March 1946 | 2 Home Farm, Aldcliffe, Lancaster, Lancashire, LA1 5AX |
| NATION, Robert Franklin RESIGNED | Director | 11 Jan 1999 | 15 Feb 2002 | | March 1926 | 1924 Market Street, Camp Hill, PA 17011, Usa |
| NAVARRA, Stephane RESIGNED | Director | 10 Dec 2010 | 30 Sep 2011 | France | August 1966 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| OAKES, Paul Harry RESIGNED | Director | 03 Oct 2011 | 01 Jul 2014 | United Kingdom | November 1957 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| PRATER, Nilon Houston RESIGNED | Director | 11 Jan 1999 | 05 Mar 1999 | | May 1928 | 992 Shipwatch Drive East, Jacksonville, FL 32225 |
| REITEMEIER, Christophe Nicolas RESIGNED | Director | 29 Dec 2020 | 02 Dec 2025 | England | December 1965 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |
| SLAUGHTER, Giles David RESIGNED | Director | 01 Feb 1999 | 15 Oct 2002 | | July 1937 | 6 Church Lane, Lower Ufford, Woodbridge, Suffolk, IP13 6DS |
| STRACHAN, Ian Charles RESIGNED | Director | 25 Apr 2002 | 11 Oct 2002 | United Kingdom | April 1943 | 30 Bloomfield Terrace, London, SW1W 8PQ |
| STUBBS, Graham Martin RESIGNED | Director | 03 Oct 2011 | 01 Jul 2014 | United Kingdom | February 1954 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| WATKINSON, John Francis Xavier, Dr RESIGNED | Director | | 10 Mar 1995 | United Kingdom | May 1929 | Old Dole Farm, Charlton Kings, Cheltenham, Gloucestershire, GL54 4HQ |
| WHISTLER, Christopher Claude Lashmer RESIGNED | Director | 10 Dec 2010 | 31 Dec 2020 | England | June 1958 | Harsco House Regent Park, 299 Kingston Road, Leatherhead, Surrey, KT22 7SG |
| WILBURN, Robert C, Dr RESIGNED | Director | 18 Jan 2000 | 11 Mar 2002 | | July 1943 | 3, Box 376, Blairsville, Pa 15717, Usa |
| WRIGHT, Joseph Hockley RESIGNED | Director | | 20 Mar 1996 | | August 1949 | 7 Kings Road, London, SW19 8PL |
| ZAMAN, Shaima RESIGNED | Director | 05 Dec 2024 | 11 Nov 2025 | England | December 1976 | Office 3a Capital Tower, 91 Waterloo Road, London, SE1 8RT, England |