| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| BRAINTREE CLINICAL SERVICES LTD | 07015937 | 10/03/2011 | Dissolved |
| Euromedic Ltd | 04210835 | 31/05/2006 | Dissolved |
| HOMECOLL SPECIALIST BAILIFF, DEBT RECOVERY & ENQUIRY AGENTS LTD | 05425203 | 24/10/2011 | Dissolved |
| INTEGRATED CLINICAL SERVICES LIMITED | 07935395 | 03/02/2012 | Dissolved |
| Itnet Ltd | 03036256 | 31/05/2006 | Dissolved |
| LISTENING LIMITED | SC264662 | 14/03/2011 | Dissolved |
| LISTENING SERVICES LIMITED | 03170478 | 14/03/2011 | Dissolved |
| MP PROJECT SERVICES LIMITED | 07346752 | 16/08/2010 | Dissolved |
| MP SERVICES (HOLDINGS NO 1) LIMITED | 07343214 | 11/08/2010 | Dissolved |
| MP SERVICES (HOLDINGS NO 2) LIMITED | 07344745 | 12/08/2010 | Dissolved |
| Manchester Tram Co Ltd | 04183241 | 31/05/2006 | Dissolved |
| PHILIPS BAILIFFS LTD | 04499413 | 24/10/2011 | Dissolved |
| PHILIPS PARKING SERVICES LIMITED | 04626908 | 24/10/2011 | Dissolved |
| PHILIPS TRAINING ACADEMY LIMITED | 06240539 | 24/10/2011 | Dissolved |
| Premier Custodial Group Ltd | 03849249 | 31/05/2006 | Dissolved |
| Premier Detention Services Ltd | 03931282 | 31/05/2006 | Dissolved |
| Premier Monitoring Services Ltd | 03522756 | 31/05/2006 | Dissolved |
| Premier Training Services Ltd | 03488626 | 31/05/2006 | Dissolved |
| RB SOLUTIONS LIMITED | 05280611 | 17/02/2010 | Dissolved |
| Railtest Operations Ltd | 03318555 | 31/05/2006 | Dissolved |
| SERCO COLLECTIONS LIMITED | 08322646 | 07/12/2012 | Dissolved |
| SERCO EUROPE LIMITED | 00451392 | 31/05/2006 | Dissolved |
| SERCO GEOGRAFIX LIMITED | 03522659 | 31/05/2006 | Dissolved |
| SERCO GULF ENGINEERING LIMITED | 02809869 | 31/05/2006 | Dissolved |
| SERCO HEALTH LIMITED | 04934828 | 31/05/2006 | Dissolved |
| SERCO INVESTMENTS (HOLDINGS) LIMITED | 04080682 | 31/05/2006 | Dissolved |
| SERCO INVESTMENTS LIMITED | 03287461 | 31/05/2006 | Dissolved |
| SERCO MANCHESTER LEISURE LIMITED | 04222446 | 31/05/2006 | Dissolved |
| SERCO PUBLIC SERVICES LIMITED | 07946083 | 09/06/2012 | Dissolved |
| SERCO-DENHOLM LIMITED | 03158133 | 31/05/2006 | Dissolved |
| Sbb Nuclear Ltd | 02947232 | 31/05/2006 | Dissolved |
| Serco Insurance Services Ltd | 03471126 | 31/05/2006 | Dissolved |
| Serco Nedrailways West Midlands Ltd | 05611363 | 31/10/2006 | Dissolved |
| Serco Overseas Investments Ltd | 02834864 | 31/05/2006 | Dissolved |
| Serco Project Development Ltd | 02834872 | 31/05/2006 | Dissolved |
| Serco Solutions Ltd | 00189075 | 31/05/2006 | Dissolved |
| Serco Systems Ltd | 01861237 | 31/05/2006 | Dissolved |
| Serco-Denholm Shipping Co Ltd | 03323056 | 31/05/2006 | Dissolved |
| Sercoserve Ltd | 02497013 | 31/05/2006 | Dissolved |
| TLC DIGITAL SOLUTIONS LIMITED | 06703791 | 14/03/2011 | Dissolved |
| TLC NEWCASTLE LIMITED | 06654312 | 14/03/2011 | Dissolved |
| TLC TONBRIDGE LIMITED | 05594037 | 14/03/2011 | Dissolved |
| TRAFFIC INFORMATION SERVICES (TIS) SECURITY LIMITED | 04071538 | 31/05/2006 | Dissolved |
| TRISKELION HEALTHCARE LIMITED | 05392761 | 31/05/2006 | Dissolved |
| Technology Transfer & Innovation Ltd | 04516382 | 31/05/2006 | Dissolved |
| Wood Green Leisure Ltd | 02659223 | 31/05/2006 | Dissolved |
| Worldwide Laundry Services Ltd | 02661336 | 31/05/2006 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| AGPLUS DIAGNOSTICS LTD | 06994240 | 30/08/2011 | 15/07/2015 | One Red Flag |
| BWP PROJECT SERVICES LIMITED | 07279250 | 20/07/2010 | 09/01/2014 | Bronze |
| BWP SERVICES (HOLDINGS NO 1) LIMITED | 07278956 | 20/07/2010 | 09/01/2014 | Bronze |
| BWP SERVICES (HOLDINGS NO 2) LIMITED | 07278972 | 20/07/2010 | 14/01/2014 | Gold |
| COLLECTICA LIMITED | 03517395 | 24/10/2011 | 19/06/2014 | One Red Flag |
| COMPASS SNI LIMITED | 07981676 | 30/11/2016 | 08/10/2021 | One Red Flag |
| CUBIC TRANSPORTATION SYSTEMS (ITMS) LIMITED | 08498086 | 22/04/2013 | 26/11/2013 | Dissolved |
| ENERGY, SAFETY AND RISK CONSULTANTS (UK) LIMITED | 07825532 | 27/10/2011 | 29/06/2012 | Amber |
| MERSEYRAIL SERVICES HOLDING COMPANY LIMITED | 04620520 | 31/05/2006 | 01/01/2007 | Silver |
| NORTHERN RAIL LIMITED | 04619954 | 31/05/2006 | 12/03/2007 | Dissolved |
| NPL MANAGEMENT LIMITED | 02937881 | 14/09/2007 | 01/01/2015 | Gold |
| SERCO CALEDONIAN SLEEPERS LIMITED | SC477821 | 16/05/2014 | 01/11/2021 | Gold |
| SERCO ENVIRONMENTAL SERVICES LIMITED | 09070246 | 04/06/2014 | 08/10/2021 | Insolvent |
| SERCO FERRIES (HR) LIMITED | 08118341 | 25/06/2012 | 08/10/2021 | Gold |
| SERCO HOLDINGS LIMITED | 03970268 | 31/05/2006 | 08/10/2021 | Silver |
| SERCO INTERNATIONAL LIMITED | 02324094 | 31/05/2006 | 08/10/2021 | Silver |
| SERCO LEASING LIMITED | 03902874 | 26/03/2008 | 08/10/2021 | Dissolved |
| SERCO LEISURE OPERATING LIMITED | 04687478 | 31/05/2006 | 16/12/2022 | Two Red Flags |
| SERCO LISTENING COMPANY LIMITED | 03651678 | 14/03/2011 | 08/10/2021 | Silver |
| SERCO NORTH AMERICA LIMITED | 06617598 | 11/06/2008 | 08/10/2021 | Dissolved |
| SERCO PENSION TRUSTEE LIMITED | 09868351 | 11/11/2015 | 08/10/2021 | Not Trading |
| SERCO PIK LIMITED | 10131554 | 19/04/2016 | 08/10/2021 | Dissolved |
| SERCO-IAL LIMITED | 00427272 | 31/05/2006 | 08/10/2021 | Silver |
| SERCO-IAL LIMITED | 00427272 | 10/07/2014 | 01/07/2020 | Silver |
| TELEPERFORMANCE GLOBAL BPO UK LIMITED | 02180352 | 08/08/2012 | 31/12/2015 | Amber |
| TELEPERFORMANCE GLOBAL SERVICES UK LIMITED | 05646273 | 08/08/2012 | 31/12/2015 | Amber |
| THE SERCO FOUNDATION | 08332279 | 17/11/2014 | 08/10/2021 | Bronze |