| Ardent Staffing Payroll Ltd | Administrative & support | 2016 |
| Areley Kings Limited | Real estate | 2012 |
| Aremzo Limited | Wholesale & retail | 2015 |
| Arena Developments Limited | Construction | 1984 |
| Ares Auto Repair Ltd | Wholesale & retail | 2024 |
| Aretex Ltd | Wholesale & retail | 2019 |
| Argo City Ltd | Wholesale & retail | 2009 |
| Argonautica Limited | Real estate | 2022 |
| ARI Capital Limited | Real estate | 2025 |
| ARI Education Services LLP | | 2025 |
| ARI Kalare Properties Ltd | Real estate | 2026 |
| Aria & Co Properties Ltd | Real estate | 2025 |
| Aria Capital Holdings Ltd | Financial services | 2025 |
| Aria Intel Ltd | Information & communication | 2026 |
| Arias Developments Ltd | Construction | 2023 |
| Arik Ltd | Transport & logistics | 2021 |
| Arise Marketing Solutions Ltd | Wholesale & retail | 2026 |
| Arise Training CIC | Education | 2019 |
| Arisglobal UK Limited | Administrative & support | 2002 |
| Arjan Transport Ltd | Transport & logistics | 2026 |
| Arjoi Ltd | Other services | 2018 |
| Arjun Chahal Ltd | Professional & scientific | 2026 |
| Arjun Logistics Limited | Transport & logistics | 2023 |
| Arjunlally Ltd | Transport & logistics | 2013 |
| ARK Accountants Limited | Administrative & support | 1997 |
| ARK Driving Academy Ltd | Education | 2026 |
| ARK ED Ltd | Education | 2021 |
| ARK Recruitment Solutions Limited | Administrative & support | 2010 |
| Arka Holdings Ltd | Financial services | 2022 |
| Arkon Safety U.K. Limited | Administrative & support | 1996 |
| Armaan Enterprises Ltd | Transport & logistics | 2026 |
| Armaan Infosystems Ltd | Information & communication | 2011 |
| Armada Classic Cars Limited | Wholesale & retail | 2020 |
| Armada Contract Hire Limited | Other services | 2017 |
| Armada Corporate Contracts Limited | Financial services | 2016 |
| Arman MOT Test Centre Ltd | Wholesale & retail | 2023 |
| Arman Motors Ltd | Wholesale & retail | 2022 |
| Armani Foods Limited | Hospitality | 2022 |
| Armantariq Ltd | Manufacturing | 2025 |
| Armin Mahal Limited | Administrative & support | 2025 |
| Armoloy (U.K.) Limited | Manufacturing | 1989 |
| Armoniy Limited | Wholesale & retail | 2026 |
| Armour Housing Group CIC | Households | 2024 |
| Arms Care Solutions Limited | Health & social care | 2023 |
| Arnazz Logistics Limited | Transport & logistics | 2026 |
| Arnis+ Ltd | Transport & logistics | 2019 |
| Arnwood Commercial Limited | Construction | 2021 |
| Arnwood Investments Group Limited | Administrative & support | 2021 |
| Arnwood MG Limited | Real estate | 2021 |
| Arnwood Residential Limited | Real estate | 2016 |
| Aroman Properties Ltd | Real estate | 2022 |
| Arooj Mart Limited | Other services | 2025 |
| Arora Foods Limited | Hospitality | 2021 |
| Arora Haulage Ltd | Transport & logistics | 2026 |
| Arora Secure Logistics Ltd | Transport & logistics | 2024 |
| Aros & an Ltd | Households | 2025 |
| Aros Market Ltd | Wholesale & retail | 2026 |
| ARP Events Ltd | Information & communication | 2025 |
| ARP Group Ltd | Real estate | 2025 |
| ARP Holds Ltd | Real estate | 2025 |
| Arpanex Limited | Wholesale & retail | 2025 |
| Arrendio Limited | Professional & scientific | 2024 |
| ARRO1 Ltd | Real estate | 2016 |
| Arron Garages Ltd | Other services | 2025 |
| Arron Transport Limited | Transport & logistics | 2005 |
| Arrow Decorators Limited | Construction | 1997 |
| Arrow Environmental Services Limited | Water & waste | 1986 |
| Arrowpoint Mail Limited | Information & communication | 2009 |
| ARS Constructions Ltd | Construction | 2025 |
| ARS Haulage Limited | Transport & logistics | 2023 |
| Arsh Ghotra Limited | Transport & logistics | 2019 |
| Arsh Rendering & Building Ltd | Construction | 2026 |
| Arsh Transport U.K. Ltd | Transport & logistics | 2023 |
| Arshad Health Ltd | Health & social care | 2014 |
| Arshee Products Ltd | Wholesale & retail | 2023 |
| Arslan Saleem Ltd | Manufacturing | 2024 |
| Art CP Ltd | Construction | 2016 |
| Art Gazette Global Limited | Wholesale & retail | 2019 |
| Art Rental Limited | Real estate | 2010 |
| Arta Freight Transport Ltd | Transport & logistics | 2016 |
| Artasand Limited | Professional & scientific | 2024 |
| Artech Carpentry Limited | Construction | 2014 |
| Arthur M Griffiths & SON (Holdings) Limited | Real estate | 2009 |
| Arthur Road Properties Limited | Real estate | 2011 |
| Artiem Developments Limited | Construction | 2022 |
| Artiem Limited | Extraterritorial | 2023 |
| Artiem Property Limited | Real estate | 2022 |
| Artifea Ltd | Information & communication | 2022 |
| Artimenesci Ltd | Manufacturing | 2022 |
| Artisan Catering Limited | Hospitality | 2020 |
| Artisan Newbridge Ltd | Arts & recreation | 2024 |
| Artisan PT Limited | Arts & recreation | 2015 |
| Artisan Sports Therapy Limited | Arts & recreation | 2019 |
| Artivo Innovations Ltd | Information & communication | 2026 |
| Artline Industries Limited | Professional & scientific | 2009 |
| Arttem Ltd | Transport & logistics | 2024 |
| Aruns Ltd | Wholesale & retail | 2024 |
| Arvello Housing Ltd | Real estate | 2026 |
| Arxion Ltd | Extraterritorial | 2025 |
| ARY Travel Ltd | Administrative & support | 2023 |