| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| ALEXANDER HUGHES INTERIM MANAGEMENT LIMITED | 04202004 | 26/11/2007 | Dissolved |
| BUSINESS LINK DEVON & CORNWALL LIMITED | 02522301 | 30/11/2007 | Dissolved |
| Bailbrook College Ltd | 04988286 | 31/05/2006 | Dissolved |
| CORNWELL MANAGEMENT CONSULTANTS PLC. | 02668512 | 28/09/2007 | Dissolved |
| E&TS LIMITED | 05577017 | 31/05/2006 | Dissolved |
| ER CONSULTANTS LTD. | 02420282 | 31/12/2007 | Dissolved |
| PREMIER PRISON SERVICES LIMITED | 02733334 | 31/05/2006 | Dissolved |
| SERCO DOCKLANDS LIMITED | 03145194 | 15/12/2006 | Dissolved |
| Serco Railtest Ltd | 03114741 | 31/05/2006 | Dissolved |
| Total I.T. Ltd | 02556546 | 31/05/2006 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| KILMARNOCK PFI HOLDINGS LIMITED | 05971387 | 06/11/2007 | 23/06/2008 | Silver |
| KILMARNOCK PRISON SERVICES LIMITED | 03226951 | 06/11/2007 | 23/06/2008 | Amber |
| MERSEYRAIL ELECTRICS 2002 LIMITED | 04356933 | 31/05/2006 | 01/08/2023 | Silver |
| NORTHERN RAIL HOLDINGS LIMITED | 04007719 | 31/05/2006 | 01/01/2007 | Dissolved |
| SD MARINE SERVICES (HOLDINGS) LIMITED | 06251300 | 17/07/2007 | 09/01/2014 | Strike Off |
| SD MARINE SERVICES LIMITED | 06251034 | 17/07/2007 | 09/01/2014 | Strike Off |
| SERCO LIMITED | 00242246 | 31/05/2006 | 08/10/2021 | Silver |
| SERCO REGIONAL SERVICES LIMITED | 01653016 | 31/05/2006 | 08/10/2021 | One Red Flag |