| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| Arup-Atkins International Ltd | 01815951 | 18/12/1992 | Dissolved |
| GHKP SERVICES LIMITED | 02033122 | 30/09/2009 | Dissolved |
| Woodhay Investments Ltd | 04000448 | 12/10/2000 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| ATKINS PLANNING & MANAGEMENT CONSULTANTS LIMITED | 00819139 | 20/09/1992 | 01/02/2000 | Dissolved |
| ATKINSRÉALIS (WS) LIMITED | 01885586 | 20/09/1992 | 01/02/2000 | Gold |
| ATKINSRÉALIS CONSULTANTS LIMITED | 00755613 | 24/09/1991 | 01/02/2000 | Dissolved |
| ATKINSRÉALIS UK INTERNATIONAL LIMITED | 01091953 | 20/09/1992 | 01/02/2000 | Silver |
| Atkins Burns & McDonnell Ltd | 02812690 | 12/11/1996 | 01/02/2000 | Dissolved |
| C3 MANAGEMENT AND ECONOMIC CONSULTING LIMITED | 04655181 | 02/01/2008 | 29/02/2012 | Dissolved |
| CMC PARTNERSHIP CONSULTANCY LTD | 11458998 | 01/10/2019 | 01/10/2021 | Gold |
| GHK HOLDINGS LIMITED | 02702417 | 01/07/2002 | 29/02/2012 | Not Trading |
| GILMORE HANKEY KIRKE LIMITED | 01192845 | 16/12/2010 | 05/02/2015 | Gold |
| ICF CONSULTING SERVICES LIMITED | 04161656 | 01/06/2006 | 29/02/2012 | Bronze |
| PROSCI UK LIMITED | 04358177 | 20/03/2003 | 30/11/2013 | Silver |