| Aroma Spice Birstall Ltd | Hospitality | 2019 |
| Aroman Care Services Ltd | Health & social care | 2019 |
| Arome Saviour Ltd | Manufacturing | 2023 |
| Aromex Ltd | Wholesale & retail | 2025 |
| Aromiq Group Ltd | Wholesale & retail | 2025 |
| Arona Holdings Ltd | Health & social care | 2024 |
| Arona Support Ltd | Administrative & support | 2018 |
| Aroos Supermarket Ltd | Wholesale & retail | 2021 |
| Aroos Supermarket Saffron Ltd | Wholesale & retail | 2022 |
| Arora Homes and Properties Ltd | Real estate | 2024 |
| Arora Trading UK Limited | Wholesale & retail | 2013 |
| ARP Health Ltd | Health & social care | 2022 |
| ARP UK Properties Ltd | Real estate | 2021 |
| Arpel Holdings Limited | Professional & scientific | 2025 |
| Arpenco Accountancy Services Limited | Professional & scientific | 2010 |
| Arpi Investment Limited | Real estate | 2018 |
| ARR Global Holdings Ltd | Real estate | 2023 |
| Arrabella Limited | Professional & scientific | 2021 |
| Arran Technology Limited | Professional & scientific | 1990 |
| Arrana Ltd | Information & communication | 2014 |
| Arrana Trading Ltd | Information & communication | 2007 |
| Arravali Essence Ltd | Wholesale & retail | 2025 |
| Arrianne Travel Ltd | Administrative & support | 2022 |
| Arribatec UK Ltd | Information & communication | 1995 |
| Arrivo Ltd | Transport & logistics | 2025 |
| Arro Consulting Limited | Professional & scientific | 2018 |
| Arron Management Ltd | Professional & scientific | 2022 |
| Arrow Conveyancing Limited | Professional & scientific | 2017 |
| Arrow Direct (Midlands) Limited | Transport & logistics | 2013 |
| Arrow Enterprises Ltd | Wholesale & retail | 2020 |
| Arrow Industrial UK Holding Ltd | Energy | 2026 |
| Arrow Textiles Limited | Wholesale & retail | 2019 |
| Arrowmere Limited | Extraterritorial | 1982 |
| Arrowtec Ltd | Construction | 2020 |
| ARS Accident Repair Solutions Ltd | Wholesale & retail | 2022 |
| ARS Sufa Holdings Ltd | Real estate | 2026 |
| Arsaa International Ltd | Administrative & support | 2023 |
| Arsad Cafe Ltd | Hospitality | 2023 |
| Arsai Phone Tech Ltd | Wholesale & retail | 2025 |
| Arseun Limited | Arts & recreation | 2020 |
| Arsh UK Holdings Ltd | Professional & scientific | 2022 |
| Arshdeep Transport Ltd | Transport & logistics | 2024 |
| Arshe Services Ltd | Transport & logistics | 2021 |
| Arshia Kunal Ltd | Health & social care | 2022 |
| Arshiakunal Properties Limited | Real estate | 2024 |
| Arsi Labs Ltd | Financial services | 2022 |
| Arslan Express Limited | Wholesale & retail | 2026 |
| Art & More Leicester Ltd | Arts & recreation | 2021 |
| Art Assets Limited | Real estate | 2022 |
| Art Consults Limited | Information & communication | 2024 |
| Art Cottage Limited | Administrative & support | 2000 |
| Art JAN Ltd | Wholesale & retail | 2021 |
| Art of Champions Ltd | Wholesale & retail | 2026 |
| Art of Management & Organization | Education | 2013 |
| Art Pattern Ltd | Manufacturing | 2011 |
| Art Radio Limited | Information & communication | 2010 |
| Art Tattoo Ltd | Other services | 2024 |
| Art's Greek Cuisine Ltd | Hospitality | 2023 |
| Artcave Ltd | Manufacturing | 2023 |
| Artemis Applications UK Ltd | Information & communication | 2023 |
| Artemis Movement Ltd | Education | 2026 |
| Artesan UK Limited | Administrative & support | 2007 |
| Arteva! Art and Design Ltd | Wholesale & retail | 2026 |
| Artful JK Ltd | Information & communication | 2023 |
| Artha Ajiti Limited | Real estate | 2024 |
| Artha IDA Limited | Financial services | 2024 |
| Arthmar Ltd | Health & social care | 2011 |
| Arthur Bennett Ltd | Hospitality | 2022 |
| Arthur Black (General Smiths) Limited | Extraterritorial | 2014 |
| Arthur Pollard Limited | Construction | 1955 |
| Arthur Prince Limited | Wholesale & retail | 1961 |
| Arthurs Electrical Ltd | Wholesale & retail | 2025 |
| Arti Spence Legal Services Ltd | Professional & scientific | 2022 |
| Artic on Road Limited | Transport & logistics | 2018 |
| Article 10 Clothing Ltd | Wholesale & retail | 2020 |
| Articura Medical Ltd | Health & social care | 2025 |
| Artifex Electricus Limited | Construction | 2026 |
| Artimovics Sergejs 0267 Limited | Transport & logistics | 2015 |
| Artisan Abode Transformations Limited | Construction | 2025 |
| Artisan Academia Limited | Wholesale & retail | 2025 |
| Artisan Carpets Limited | Wholesale & retail | 2019 |
| Artisan Fayre Ltd | Manufacturing | 2024 |
| Artisan Hire Services Limited | Wholesale & retail | 2023 |
| Artisan Joinery Holdings Limited | Financial services | 2023 |
| Artisan Retail Display Limited | Manufacturing | 2005 |
| Artisan Solar Power Limited | Manufacturing | 2024 |
| Artist Printing Ltd | Manufacturing | 2025 |
| Artistiq Automobiles Ltd | Wholesale & retail | 2025 |
| Artkam Ltd | Wholesale & retail | 2017 |
| Arton Capital Ltd | Information & communication | 2024 |
| Arton Joinery Ltd | Manufacturing | 2023 |
| Artond Ltd | Wholesale & retail | 2022 |
| Artonomy Projects C.I.C. | Education | 2019 |
| Artos Tooling Engineers Limited | Manufacturing | 1988 |
| Artreach (Trust) Ltd | Arts & recreation | 2008 |
| Artstamp Limited | Information & communication | 2025 |
| Artsy Agency Ltd | Information & communication | 2020 |
| Artur Adam Jablonski Ltd | Extraterritorial | 2024 |
| Artursitsupport Ltd | Information & communication | 2026 |
| Arufandika Care and Supported Living Limited | Health & social care | 2015 |