| Armory UK Ltd | Wholesale & retail | 2025 |
| Armoured Knight Services Limited | Administrative & support | 2025 |
| Armstrong & Burns Ltd | Administrative & support | 2017 |
| Armstrong Oiler Company Limited | Manufacturing | 1903 |
| Armstrong Priestley Holdings Limited | Financial services | 2016 |
| Armtech Property Innovations Ltd | Construction | 2022 |
| Armytage Ltd | Administrative & support | 2018 |
| ARN (Hldg) Ltd | Construction | 2016 |
| ARN Assets Ltd | Real estate | 2016 |
| ARN Assets TP Ltd | Real estate | 2023 |
| ARN Capital Group Ltd | Financial services | 2025 |
| ARN Capital Ltd | Real estate | 2015 |
| ARN Capital SPV1 Ltd | Real estate | 2023 |
| ARN Capital SPV2 Ltd | Real estate | 2023 |
| ARN Management Ltd | Real estate | 2015 |
| Arn-Comms Limited | Information & communication | 2018 |
| Arnai Beds Ltd | Administrative & support | 2024 |
| Arnai UK Ltd | Manufacturing | 2023 |
| Arnall-Phillips Limited | Construction | 2013 |
| Arncliffe Court (Maintenance) Limited | Households | 1967 |
| Arncliffe Grange (Moortown) Maintenance Limited | Households | 1974 |
| Arncliffe Homes Limited | Construction | 1991 |
| Arncliffe House (Maintenance) Limited | Households | 1984 |
| Arncliffe Road Management Company Limited | Real estate | 2003 |
| Arncliffe Road PM Company Limited | Households | 2018 |
| Arndale House Liverpool RTM Company Limited | Extraterritorial | 2021 |
| Arndale Solicitors Limited | Professional & scientific | 2016 |
| Arnold Armstrong Limited | Administrative & support | 2021 |
| Arnold Family Properties Limited | Real estate | 2016 |
| Arnold Securities Limited | Other services | 1969 |
| Arnold Stratford Properties Ltd | Hospitality | 2024 |
| ARO Healthcare Management Ltd | Health & social care | 2026 |
| ARO Maintenances Ltd | Construction | 2023 |
| ARO Transport Ltd | Transport & logistics | 2022 |
| Aroma Coffee Lounge Ltd | Hospitality | 2025 |
| Aroma Prestige UK Ltd | Wholesale & retail | 2020 |
| Aroma Properties Limited | Real estate | 2000 |
| Aroma Thai Therapy Limited | Health & social care | 2017 |
| Aromas Wholesale Ltd | Wholesale & retail | 2005 |
| Aromatik Ltd | Hospitality | 2024 |
| Aromiq Fragrances Ltd | Wholesale & retail | 2025 |
| Aronel Ltd | Construction | 2026 |
| Arowra Limited | Wholesale & retail | 2019 |
| Arpita Ltd | Administrative & support | 2016 |
| ARQ Insights Ltd | Information & communication | 2025 |
| Arqera Capital Limited | Financial services | 2026 |
| Arran Aromatics Limited | Manufacturing | 2013 |
| Arris Heating Solutions Ltd | Construction | 2022 |
| Arrival Entertainment Ltd | Arts & recreation | 2025 |
| Arronie Limited | Wholesale & retail | 2025 |
| Arrose Limited | Manufacturing | 2013 |
| Arroteq Ltd | Information & communication | 2022 |
| Arrow Estates & Property Developments Limited | Real estate | 1989 |
| Arrow Fresh Limited | Hospitality | 2020 |
| Arrow Simulation Limited | Professional & scientific | 1994 |
| Arrowglass Commercial Ltd | Construction | 2019 |
| Arrowsmith Medical Limited | Health & social care | 2025 |
| Arrs Properties Limited | Real estate | 2018 |
| Arsenal Properties Ltd | Real estate | 2026 |
| Arslan Mahmood Ltd | Professional & scientific | 2017 |
| Art 4 Walls Limited | Arts & recreation | 2002 |
| Art Centre (Leeds) Ltd | Real estate | 2010 |
| Art Estate Management Ltd | Real estate | 2024 |
| Art ILK Limited | Wholesale & retail | 2023 |
| Art of Cloud Ltd | Information & communication | 2016 |
| Art of Truth Ltd | Information & communication | 2020 |
| Art Stone Real Estate Ltd | Real estate | 2021 |
| Art Temple Ltd | Wholesale & retail | 2025 |
| Artanu Limited | Arts & recreation | 2024 |
| Artco (Leeds) Ltd | Wholesale & retail | 2014 |
| Arteam Ltd | Transport & logistics | 2014 |
| Artelean Limited | Professional & scientific | 2023 |
| Artemi Consultants Ltd | Information & communication | 2012 |
| Artemis Accessories Ltd | Wholesale & retail | 2025 |
| Artemis Providers Ltd | Health & social care | 2026 |
| Arterius Limited | Professional & scientific | 2009 |
| Artexworld Limited | Wholesale & retail | 2003 |
| Artha Finance Limited | Professional & scientific | 2025 |
| Arthur Brown (Insurance Brokers) Limited | Financial services | 1931 |
| Arthur Brownridge & SON Limited | Professional & scientific | 1962 |
| Arthur Browns Wealth Management Ltd | Financial services | 2007 |
| Arthur Careline Services Ltd | Administrative & support | 2021 |
| Arthur Court (Pudsey) Management Company Limited | Households | 2015 |
| Arthur Foodstores Limited | Wholesale & retail | 2022 |
| Arthur Greaves Investments Limited | Real estate | 2007 |
| Arthur Greaves Limited | Real estate | 1919 |
| Arthur Rostron & Sons Limited | Manufacturing | 1958 |
| Arthur Welham Limited | Wholesale & retail | 1941 |
| Articstar Limited | Professional & scientific | 2017 |
| Artificial Grass Leeds Ltd | Construction | 2015 |
| Artificial Intelligence Venture Ltd | Financial services | 2021 |
| Artify LAB Ltd | Information & communication | 2026 |
| Artis Finance Limited | Financial services | 2020 |
| Artisan Furniture Ltd | Wholesale & retail | 2023 |
| Artisan Prism Ltd | Wholesale & retail | 2025 |
| Artisan Touch Ltd | Administrative & support | 2026 |
| Artist Needs Limited | Transport & logistics | 2004 |
| Artium (Commercial) Developments Limited | Construction | 2024 |
| Artium (Ripon) Developments Limited | Real estate | 2022 |
| Artium (RPH) Limited | Real estate | 2026 |