| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| Halcrow S.E.A. Limited | 02305963 | 15/11/1991 | Dissolved |
| Halcrow-Balfour Ltd | 01409976 | 01/12/1991 | Dissolved |
| S W H P Ltd | 01244911 | 15/11/1991 | Dissolved |
| Sir William Halcrow & Partners (Greece) Ltd | 02363479 | 24/09/1991 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| BIWATER HOLDINGS LIMITED | 00929686 | 01/11/2002 | 13/12/2006 | Three Red Flags (Highest) |
| BOURNEMOUTH WATER LIMITED | 02924312 | 21/09/2001 | 26/07/2002 | Dissolved |
| BURDEROP INVESTMENTS LIMITED | 02485284 | 01/05/1996 | 30/04/1999 | Dissolved |
| CAREER CONSULTANTS ON-LINE LTD | 03690910 | 31/12/1998 | 15/12/2015 | Gold |
| CROUCH HOGG WATERMAN LIMITED | SC136186 | 03/06/1997 | 19/06/1997 | Dissolved |
| HALCROW (CONSULTING ENGINEERS & ARCHITECTS) LIMITED | 01045458 | 15/11/1991 | 30/04/1999 | Amber |
| HALCROW ASIA LIMITED | 02458827 | 01/12/1992 | 30/04/1999 | One Red Flag |
| HALCROW ASIA PARTNERSHIP LIMITED | 02490667 | 01/12/1991 | 14/05/1992 | One Red Flag |
| HALCROW GILBERT ASSOCIATES LIMITED | 02312495 | 01/12/1991 | 15/07/1996 | Dissolved |
| HALCROW GROUP LIMITED | 03415971 | 03/04/1998 | 30/04/1999 | Amber |
| HALCROW H&S LIMITED | 02288955 | 15/11/1991 | 01/12/1994 | Dissolved |
| HALCROW HOLDINGS LIMITED | 01674044 | 06/09/1991 | 30/04/1999 | One Red Flag |
| HALCROW INTERNATIONAL LIMITED | 02326765 | 15/11/1991 | 30/04/1999 | Amber |
| HALCROW MANAGEMENT SCIENCES LIMITED | 02770883 | 26/01/1993 | 19/06/1997 | Dissolved |
| HALCROW RURAL MANAGEMENT LIMITED | 02603242 | 11/07/1991 | 01/04/1999 | Dissolved |
| HALCROW WATER SERVICES LIMITED | 03055857 | 05/06/1995 | 04/06/1997 | Dissolved |
| Halcrow Gulf Ltd | 02616368 | 28/06/1991 | 30/04/1999 | Dissolved |
| Halcrow McLachlan Ltd | 02338761 | 05/06/1990 | 30/04/1999 | Dissolved |
| KEW LODGE MANAGEMENT CO.LIMITED | 00784475 | 26/01/1999 | 01/03/2008 | Silver |
| KEW LODGE MANAGEMENT CO.LIMITED | 00784475 | 26/01/1999 | 20/11/2015 | Silver |
| SEMBCORP (U.K) LIMITED | 02328585 | 19/03/2002 | 04/07/2002 | Dissolved |
| SEMBCORP UTILITIES SERVICES LIMITED | 03757398 | 07/12/2000 | 04/07/2002 | Gold |
| SHORTLANDS INVESTMENTS LIMITED | 02486041 | 22/04/1996 | 19/12/1997 | Dissolved |
| SIR WILLIAM HALCROW & PARTNERS LIMITED | 01722541 | 15/11/1991 | 30/04/1999 | Dissolved |
| STANTEC TREATMENT HOLDING LIMITED | 05728439 | 06/02/2007 | 23/12/2010 | Dissolved |
| SWAN GROUP | 02288754 | 01/07/1997 | 21/02/2001 | Silver |