| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| ALSTEC AUTOMATION LIMITED | 03979467 | 28/06/2017 | Strike Off |
| ALSTEC DEFENCE LIMITED | 03979454 | 28/06/2017 | Strike Off |
| DEVONPORT ROYAL DOCKYARD LIMITED | 02077752 | 19/02/2020 | One Red Flag |
| Future Valleys Ltd | 06493876 | 05/02/2008 | Dissolved |
| GREAT BRITISH NUCLEAR | 05027024 | 29/03/2023 | Silver |
| SICON CONSULTING LIMITED | 05622715 | 15/11/2005 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| BABCOCK ENVIRONMENTAL SERVICES LIMITED | 06122711 | 28/06/2017 | 01/12/2019 | Dissolved |
| BABCOCK MARINE (CLYDE) LIMITED | SC220243 | 15/11/2019 | 12/11/2021 | Silver |
| BABCOCK SERVICES GROUP LIMITED | 03939840 | 28/06/2017 | 01/09/2021 | Silver |
| BIL SOLUTIONS LIMITED | 02888907 | 31/03/2017 | 01/12/2019 | Dissolved |
| BIOFUELS WALES LIMITED | 05812342 | 19/02/2007 | 11/05/2015 | Dissolved |
| BUSINESS CONNECT NEATH PORT TALBOT LIMITED | 03181914 | 18/12/2001 | 30/09/2004 | Strike Off |
| CAVENDISH BOCCARD NUCLEAR LIMITED | 08335068 | 01/12/2015 | 01/09/2021 | Amber |
| CAVENDISH DOUNREAY PARTNERSHIP LIMITED | 07868218 | 01/07/2016 | 01/09/2021 | Gold |
| CAVENDISH FLUOR PARTNERSHIP LIMITED | 08980374 | 18/12/2015 | 01/09/2021 | Amber |
| CAVENDISH NUCLEAR (OVERSEAS) LIMITED | 05339062 | 01/12/2015 | 01/09/2021 | Not Trading |
| CAVENDISH NUCLEAR LIMITED | 03975999 | 01/12/2015 | 01/09/2021 | One Red Flag |
| COED DARCY LIMITED | 00577934 | 26/05/2000 | 17/12/2002 | One Red Flag |
| DOUNREAY SITE RESTORATION LIMITED | SC307493 | 01/12/2015 | 31/03/2020 | Bronze |
| EA TECHNOLOGY LIMITED | 02566313 | 26/06/2014 | 03/12/2015 | Silver |
| EEF LIMITED | 05950172 | 31/05/2017 | 07/11/2019 | Silver |
| ENVIRONMENTAL FUELS LTD | 04165107 | 11/05/2006 | 06/03/2008 | One Red Flag |
| Fuel Developments Ltd | 06457524 | 19/12/2007 | 06/03/2008 | Dissolved |
| INS INNOVATION LIMITED | 04109440 | 28/06/2017 | 01/12/2019 | Dissolved |
| Micro Heat Ltd | 04311517 | 01/05/2005 | 31/01/2006 | Dissolved |
| NEOS NUCLEAR LIMITED | 02763400 | 01/12/2015 | 18/09/2020 | Insolvent |
| NUCLEAR RESTORATION SERVICES LIMITED | 02264251 | 01/12/2015 | 31/08/2019 | Amber |
| RESEARCH SITES RESTORATION LIMITED | 05915837 | 01/12/2015 | 31/08/2019 | Silver |
| ROLLS-ROYCE SUBMARINES LIMITED | 00620485 | 13/12/2021 | 27/03/2023 | Silver |
| SCARBOROUGH POWER LIMITED | 05871176 | 09/04/2009 | 29/10/2010 | Dissolved |
| THE BRYNHYFRYD DENTAL PRACTICE LIMITED | 07713274 | 30/08/2016 | 31/10/2017 | One Red Flag |
| THE COMPANY OF PROPRIETORS OF THE NEATH CANAL NAVIGATION | ZC000173 | 27/06/2000 | 30/09/2005 | Dissolved |
| U-BATTERY LIMITED | 07479467 | 01/02/2011 | 11/04/2011 | Dissolved |
| UKAEA LIMITED | 05597709 | 31/03/2017 | 01/12/2019 | Dissolved |
| URENCO CHEMPLANTS LIMITED | 06228208 | 18/01/2011 | 21/07/2015 | Amber |
| URENCO NUCLEAR STEWARDSHIP LIMITED | 04113197 | 21/11/2011 | 21/07/2015 | Amber |
| URENCO UK LIMITED | 01144899 | 01/02/2011 | 07/09/2015 | Silver |