| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| CKI NUMBER 1 LIMITED | 07284853 | 16/01/2012 | Gold |
| CKI NUMBER 2 LIMITED | 07282841 | 16/01/2012 | Gold |
| CKI NUMBER 3 LIMITED | 07281892 | 16/01/2012 | Amber |
| CKI UK CO 5 LIMITED | 07509455 | 18/01/2012 | Silver |
| CKI UK CO 6 LIMITED | 07509449 | 18/01/2012 | Bronze |
| EASTERN POWER NETWORKS PLC | 02366906 | 08/06/2011 | Bronze |
| EVERSHOLT UK RAILS LIMITED | 10779525 | 19/05/2017 | Bronze |
| LONDON POWER NETWORKS PLC | 03929195 | 08/06/2011 | Silver |
| NORTHUMBRIAN SERVICES LIMITED | 03114615 | 17/10/2016 | Silver |
| NORTHUMBRIAN WATER GROUP LIMITED | 04760441 | 14/10/2011 | Amber |
| NORTHUMBRIAN WATER LIMITED | 02366703 | 14/10/2011 | Amber |
| SEABANK POWER LIMITED | 02591188 | 16/06/2011 | Gold |
| SOUTH EASTERN POWER NETWORKS PLC | 03043097 | 08/06/2011 | Silver |
| UK POWER NETWORKS HOLDINGS LIMITED | 07290590 | 08/06/2011 | Bronze |
| UK POWER NETWORKS SERVICES HOLDINGS LIMITED | 07306419 | 08/06/2011 | Silver |
| WALES & WEST GAS NETWORKS (HOLDINGS) LIMITED | 05095454 | 10/10/2012 | Silver |
| WALES & WEST UTILITIES FINANCE PLC | 06766848 | 10/10/2012 | Silver |
| WALES & WEST UTILITIES HOLDINGS LIMITED | 07092596 | 10/10/2012 | Silver |
| WALES & WEST UTILITIES LIMITED | 05046791 | 10/10/2012 | Silver |
| WEST & WESTERN MIDCO FINANCE PLC | 15124716 | 08/09/2023 | Silver |
| WEST GAS NETWORKS LIMITED | 08151511 | 10/10/2012 | Silver |
| WESTERN GAS NETWORKS LIMITED | 08151473 | 10/10/2012 | Silver |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|