| Arsala Ltd | Health & social care | 2012 |
| Arsalan Collection HA Ltd | Wholesale & retail | 2022 |
| Arsh International Ltd | Administrative & support | 2018 |
| Arsh Ltd | Wholesale & retail | 2025 |
| Arshi Solutions Ltd | Construction | 2024 |
| Arshiv Trading Limited | Wholesale & retail | 2025 |
| Art Decor Walls & Finishes Ltd | Construction | 2025 |
| Art Karat Global Limited | Manufacturing | 1999 |
| Art of Beauty Pro Ltd | Other services | 2025 |
| Art of Drone Limited | Professional & scientific | 2021 |
| Art of Living Film Ltd | Information & communication | 2021 |
| Art of the Mind Ltd | Information & communication | 2025 |
| Art Price Point Limited | Wholesale & retail | 2025 |
| Art Vivant UK Limited | Wholesale & retail | 2020 |
| Artdent Ltd | Health & social care | 2020 |
| Artec Electrical Limited | Construction | 2013 |
| Artemis Associates Limited | Professional & scientific | 2019 |
| Artemis Education Limited | Education | 2010 |
| Artemis Projex Holdings Limited | Financial services | 2025 |
| Artemis Projex Ltd | Construction | 2025 |
| Artemis Recruitment Ltd. | Other services | 2000 |
| Artezen London Ltd | Wholesale & retail | 2020 |
| Arth Direct Limited | Wholesale & retail | 2026 |
| Arthur Building Ltd | Construction | 2019 |
| Arthur International UK Private Ltd | Wholesale & retail | 2025 |
| Arthur MIX Limited | Transport & logistics | 2018 |
| Arthur Property Management Company Limited | Real estate | 2020 |
| Arthur Windows Ltd | Construction | 2004 |
| Arthur's Seat Limited | Information & communication | 2021 |
| Arthxetra Limited | Administrative & support | 2023 |
| Artificial Green House Ltd | Administrative & support | 2016 |
| Artisan Court Holdings Ltd | Real estate | 2024 |
| Artisan Court Ltd | Construction | 2017 |
| Artisan Flower Group Limited | Wholesale & retail | 2015 |
| Artisan Transformation Ltd | Construction | 2022 |
| Artisanal One (UK) Ltd | Manufacturing | 2023 |
| Artium (PVT) Limited | Information & communication | 2025 |
| Artivian CIC | Arts & recreation | 2025 |
| Artlandscapes Ltd | Administrative & support | 2018 |
| Artlimes Ltd. | Information & communication | 2016 |
| Artorius Alexander Limited | Administrative & support | 2020 |
| Arts & Crafts Maintenance Company Ltd | Manufacturing | 2022 |
| Arts Advance Ltd | Arts & recreation | 2020 |
| Artscounsel Limited | Administrative & support | 2016 |
| Aruban Property Ltd | Construction | 2021 |
| Aruchar Investments Limited | Professional & scientific | 2013 |
| Arugula Spruce Limited | Real estate | 2016 |
| Arun Jewellery London Ltd | Wholesale & retail | 2024 |
| Arun Jewellery Ltd | Manufacturing | 2022 |
| Arun Textiles Ltd | Wholesale & retail | 2024 |
| Arun&Co Ltd | Professional & scientific | 2022 |
| Aruna Ltd | Wholesale & retail | 2016 |
| Arundel Corporation Limited | Real estate | 2024 |
| Arvandana Holdings Ltd | Financial services | 2025 |
| Arvantis Advisory Ltd | Administrative & support | 2026 |
| Arved Colvin-Smith Limited | Professional & scientific | 2011 |
| Arvena Trendz Limited | Wholesale & retail | 2026 |
| Arvind Jobanputra Insurance Services Limited | Financial services | 1984 |
| ARW (UK) Ltd | Professional & scientific | 2010 |
| ARY Cleaning Services Ltd | Administrative & support | 2025 |
| Arya Events Ltd | Hospitality | 2022 |
| Aryaba Limited | Health & social care | 2023 |
| Aryalis Clinic Ltd | Other services | 2018 |
| Aryan Holdings Ltd | Real estate | 2020 |
| Aryan Investments Limited | Real estate | 2022 |
| Aryana Property Management Ltd | Real estate | 2020 |
| Aryash Health Limited | Health & social care | 2026 |
| Aryash Solutions Ltd | Information & communication | 2017 |
| Aryeet Limited | Information & communication | 2017 |
| Arys Contractors Ltd | Construction | 2020 |
| ARZ Enterprises Ltd | Wholesale & retail | 2025 |
| AS IT Grows Limited | Administrative & support | 2001 |
| AS Learning Plus Limited | Education | 2025 |
| AS Medical Locums Ltd | Health & social care | 2022 |
| AS Real Estate Investments Ltd | Real estate | 2019 |
| AS Sabirun Motor Sales Ltd | Wholesale & retail | 2016 |
| AS92 Medical Services Limited | Health & social care | 2025 |
| ASA 2000 Limited | Arts & recreation | 2024 |
| ASA Advisory Ltd | Other services | 2025 |
| ASA Consulting Limited | Information & communication | 2022 |
| ASA Fashion Limited | Manufacturing | 2017 |
| Asactrans Ltd | Transport & logistics | 2019 |
| Asaid Ltd | Health & social care | 2022 |
| Asaka Ltd | Professional & scientific | 2018 |
| ASB Harrow Limited | Real estate | 2023 |
| ASB Investment Group Limited | Financial services | 2022 |
| ASC Prime Capital Holdings Ltd | Professional & scientific | 2024 |
| ASC Wellingborough Limited | Wholesale & retail | 2025 |
| Ascarn Ltd | Professional & scientific | 2020 |
| Ascend Advisory Limited | Professional & scientific | 2020 |
| Ascend Aerial Ltd | Information & communication | 2025 |
| Ascend Consulting Partners Ltd | Information & communication | 2025 |
| Ascense AI Ltd | Information & communication | 2025 |
| Ascentia Support Services Ltd | Health & social care | 2021 |
| Aschfords Law LLP | | 2011 |
| Aschfords Law Solicitors Limited | Professional & scientific | 2017 |
| Asco Fixings Limited | Manufacturing | 1998 |
| Asco INT Limited | Real estate | 2017 |
| Ascoman LLP | | 2008 |
| Ascot Cardiology Ltd | Health & social care | 2023 |