| ADT (UK) Holdings Limited | Sunbury On Thames | 1996 |
| ADT Accountants and Taxation Advisors Ltd | Bristol | 2013 |
| ADT Analytics Limited | Benfleet | 2025 |
| ADT Business & Tax Ltd | London | 2025 |
| ADT Consultancy Ltd | Wembley | 2026 |
| ADT Consulting Limited | Milton Keynes | 2023 |
| ADT Fencing and Groundwork’S. Ltd | South Ockendon | 2026 |
| ADT Group Limited | Sunbury On Thames | 1990 |
| ADT Medical & Public Health Consulting Limited | Liverpool | 2024 |
| ADT Services Ltd | Potters Bar | 2026 |
| ADT Strategic Ltd | Edinburgh | 2024 |
| ADT Trustees Limited | Sunbury On Thames | 1975 |
| Adtai Limited | Bexleyheath | 2016 |
| Adtarget Media Ltd | London | 2019 |
| Adtc Ltd. | Manchester | 1995 |
| Adtech Commercial Consulting Ltd | London | 2021 |
| Adtech Holdings Limited | Stroud | 2017 |
| Adtech Recruitment Limited | Wanstead | 2021 |
| Adtech Solutions Ltd | London | 2024 |
| Adtechlab Ltd | Fareham | 2020 |
| Adtechnicals Limited | London | 2019 |
| Adtechoptima Limited | Lancaster | 2024 |
| Adtent Media Ltd | London | 2022 |
| Adtentus Limited | Kings Langley | 2007 |
| Adtermino Ltd | Aberdeen | 2019 |
| Adthera BIO Limited | Birmingham | 2022 |
| Adthion Limited | Altrincham | 2023 |
| Adtlas Marketing Limited | Watford | 2024 |
| Adtops Solution Ltd | Bristol | 2022 |
| Adtower GB Limited | London | 2022 |
| Adtrailers Limited | Huddersfield | 2019 |
| Aduba Limited | London | 2016 |
| Aducate Ltd | London | 2023 |
| Aduco Consultancy Services GB Limited | Malton | 2019 |
| Aduk Products Limited | Nuneaton | 2011 |
| Adukus Law Limited | London | 2014 |
| Adullam Consulting Ltd | London | 2026 |
| Adult Care Assessment Limited | Shoreham-By-Sea | 2014 |
| Adult Care Consultants Ltd | Derby | 2021 |
| Adult Child Health and Environmental Support Ltd | Hook | 2023 |
| Adult Model Accountancy Services Limited | Coventry | 2024 |
| Adumatech Limited | Kinross | 2017 |
| Adur Partners Limited | Brighton | 2014 |
| Adur Valley Vets Limited | Lancing | 2019 |
| Adura Design Limited | London | 2020 |
| Adura Marketing Limited | Mildenhall | 2022 |
| Adura Solutions Limited | Ilford | 2018 |
| Adurja Services Ltd | Rainham | 2025 |
| Aduro Communications Limited | London | 2011 |
| Adus Holding Limited | London | 2016 |
| Aduwa Limited | South Cerney | 2023 |
| ADV Architecture Ltd | Llanymynech | 2022 |
| ADV BR UK - International Legal Consulting Ltd | London | 2022 |
| ADV Central Ltd | London | 2018 |
| ADV Digital Solutions Ltd | Ipswich | 2022 |
| ADV Grid Ltd | Bridgwater | 2020 |
| ADV M&A Group Ltd | London | 2023 |
| ADV Management Ltd | London | 2024 |
| ADV Technologies Limited | Oxford | 2014 |
| ADV3RTISING and MARK3TING Ltd | London | 2022 |
| Adva International Ltd | Dagenham | 2018 |
| Advace Ltd. | London | 2011 |
| Advaens Limited | London | 2014 |
| Advaisio Associates Ltd | London | 2024 |
| Advaisor International Ltd | London | 2022 |
| Adval Ltd | Hunstanton | 2020 |
| Advaland Farming Company Limited | Norwich | 1997 |
| Advalor Limited | London | 2020 |
| ADVALU2U Ltd | Newcastle Upon Tyne | 2020 |
| Advalue Ltd | London | 2025 |
| Advalus Limited | Bath | 2003 |
| Advameen Ltd | London | 2022 |
| Advana Capital Advisors Limited | Pinner | 2025 |
| Advancd Ltd | Gloucester | 2020 |
| Advance 6 Limited | Brighton | 2013 |
| Advance Accountancy Limited | Southport | 2016 |
| Advance Accountancy Services Limited | Rossendale | 2017 |
| Advance Accounting (NI) Ltd | Dungannon | 2014 |
| Advance Accounting Solutions Ltd | Ewloe | 2010 |
| Advance Acumen Ltd | London | 2022 |
| Advance Advisory Ltd | London | 2022 |
| Advance Aero Ltd | London | 2019 |
| Advance and Beyond Ltd | London | 2026 |
| Advance Approval Consultancy Services Ltd | Norwich | 2003 |
| Advance Architects Limited | Sowerby Bridge | 2017 |
| Advance Audit Limited | Southport | 2016 |
| Advance Automation Consultancy Ltd | Oxfordshire | 2024 |
| Advance Automation Ltd | Tamworth | 2010 |
| Advance B Holdings Limited | Greater London | 2024 |
| Advance Bidco Limited | Bristol | 2015 |
| Advance Bookkeepers Ltd | Glasgow | 2023 |
| Advance Building Designs Limited | Newtown | 2014 |
| Advance Business Coaching Ltd | Rugeley | 2021 |
| Advance Business Communications Limited | Upminster | 1998 |
| Advance Business Consultants Ltd | Mildenhall | 2023 |
| Advance Business Services Ltd | Blackpool | 2018 |
| Advance Change Ltd | St. Albans | 2008 |
| Advance Claims UK Ltd | Huddersfield | 2008 |
| Advance Coach Ltd | Dromore | 2015 |
| Advance Coaching Solutions Ltd | Kenilworth | 2010 |