| Admin Ace Limited | Peterborough | 2021 |
| Admin Alchemist Ltd | Bury St. Edmunds | 2020 |
| Admin Allies Limited | Banstead | 2025 |
| Admin and More Ltd | Northampton | 2017 |
| Admin Angels Limited | London | 2015 |
| Admin by Carrie Ltd | Macclesfield | 2025 |
| Admin Care Ltd | Bury St. Edmunds | 2022 |
| Admin Cloud Limited | Bingley | 2011 |
| Admin Consultants UK Ltd | London | 2017 |
| Admin Crew Ltd | Gravesend | 2023 |
| Admin Essentials Ltd | Grimsby | 2019 |
| Admin ETC Ltd | Oxted | 2023 |
| Admin Folio Limited | Birmingham | 2025 |
| Admin Helpers Limited | Darlington | 2008 |
| Admin Inc Ltd | Colchester | 2017 |
| Admin Kingdom Limited | London | 2023 |
| Admin Kismat Ltd | Preston | 2025 |
| Admin Ladies Ltd | London | 2021 |
| Admin Link Limited | Sidcup | 2012 |
| Admin Management Ltd | London | 2024 |
| Admin N E Ltd | Newcastle Upon Tyne | 2015 |
| Admin Ninjas Ltd | Stourbridge | 2022 |
| Admin NO. 1 Ltd | Bury St. Edmunds | 2019 |
| Admin on Demand Ltd | Croydon | 2022 |
| Admin Outsource Ltd | Leamington Spa | 2024 |
| Admin Plus Ltd | Isle Of Arran | 2019 |
| Admin Pro Limited | Billericay | 2025 |
| Admin Services Limited | St. Helens | 2017 |
| Admin Shine Limited | Mitcham | 2023 |
| Admin Skill Limited | Mitcham | 2022 |
| Admin Solutions Ltd | London | 2023 |
| Admin Support NOW Ltd | London | 2025 |
| Admin Support Specialist Limited | Gateshead | 2022 |
| Admin Svcs Ltd | Kington | 2003 |
| Admin [Bytes] (Barton) Limited | Carnforth | 2018 |
| Admin&Co Ltd | London | 2024 |
| Admin-It Ltd | London | 2026 |
| Admin-Shed Ltd | Worksop | 2025 |
| ADMIN24 (UK) Limited | London | 2012 |
| ADMIN2DAY Ltd | St. Albans | 2020 |
| ADMIN8 Ltd | Aldershot | 2026 |
| Adminanswers NI Ltd | Londonderry | 2020 |
| Admincareers Limited | Newcastle Upon Tyne | 2026 |
| Adminco Ltd | Chorleywood | 2023 |
| Admincore Ltd | Doncaster | 2025 |
| Adminday Ltd | Milton Keynes | 2025 |
| Adminex Solutions UK Ltd | London | 2013 |
| Adminimal Ltd. | Liskeard | 2018 |
| Adminimiser Limited | Wadhurst | 2011 |
| Adminique Ltd | Ringwood | 2025 |
| Adminiservices Performances Limited | London | 2025 |
| Administaff Limited | Bournemouth | 2023 |
| Administer Limited | Ipswich | 2012 |
| Administering Archaeology Company Limited | London | 2023 |
| ADMINISTR8 Ltd | Winslow | 2015 |
| Administrated Services Ltd | Lydney | 2017 |
| Administration (Wellingborough) Limited | Letchworth Garden City | 1968 |
| Administration Associates Limited | Ashford | 2015 |
| Administration Company Limited | Eastbourne | 1995 |
| Administration Management Consultants Limited | Southampton | 2026 |
| Administration Partners Group (APG) Ltd | Sunderland | 2026 |
| Administration Plus Limited | Glasgow | 2013 |
| Administration Services Limited | York | 1988 |
| Administration Support Ltd | London | 2024 |
| Administrative and Professional Services Ltd | Bromley | 2023 |
| Administrative and Support Services Limited | Bristol | 2005 |
| Administrative Assist Bolton Ltd | Bolton | 2016 |
| Administrative Ltd | Gerrards Cross | 2023 |
| Administrative Services Bureau Ltd | London | 2019 |
| Administrative Solutions DX Limited | London | 2021 |
| Administrative Support Limited | London | 2021 |
| Adminity Limited | Haywards Heath | 2025 |
| Adminiy Ltd | Swindon | 2012 |
| Adminnovate Ltd | Poole | 2024 |
| Admino Ltd | Oldham | 2025 |
| Adminops Limited | Limavady | 2025 |
| Adminova Solutions Limited | L | 2024 |
| Adminowl Ltd | Islington | 2022 |
| Adminpenguin Ltd | London | 2026 |
| Adminpower Ltd | London | 2023 |
| Adminreview Ltd | Bury | 2023 |
| Adminstream Ltd | Southport | 2022 |
| Adminsupports UK Ltd | Greater London | 2023 |
| Admintia Services Ltd | Goole | 2025 |
| Admintide Ltd | London | 2025 |
| Adminworks Ltd | Basingstoke | 2009 |
| Admirable Care Ltd | Brentford | 2020 |
| Admirable Locksmiths Limited | Brighton | 2004 |
| Admiral Building & Construction Limited | Norwich | 2008 |
| Admiral Commercial Cleaning Group Ltd | Fareham | 2020 |
| Admiral Commercial Cleaning Ltd | Norwich | 2016 |
| Admiral Fire Systems Limited | Reigate | 2019 |
| Admiral Professionals Ltd | London | 2020 |
| Admiral RAD Limited | London | 2007 |
| Admiral Recruitment Limited | London | 1995 |
| Admiral Security Ltd | Birmingham | 2017 |
| Admiral Security Systems Limited | Reigate | 1992 |
| Admiral Service & Maintenance Limited | St Mellons Road | 2007 |
| Admiral Staffing Limited | Hayes | 2025 |
| Admiral Travel UK Limited | Stockport | 2000 |