| AR & PR Consultants Ltd | Other services | 2025 |
| AR 8 Estates Ltd | Real estate | 2025 |
| AR Art Consulting Ltd. | Other services | 2013 |
| AR Bharat Ltd | Construction | 2026 |
| AR Construction Ltd | Construction | 2018 |
| AR Dispoware Ltd | Wholesale & retail | 2025 |
| AR Jewllery Ltd | Wholesale & retail | 2024 |
| AR Legal Services Limited | Professional & scientific | 2025 |
| AR Style Limited | Wholesale & retail | 2017 |
| AR Transport & Distribution Ltd | Transport & logistics | 2025 |
| AR Worldwide Services Ltd | Financial services | 2019 |
| Ar-Cleaning Ltd | Administrative & support | 2021 |
| ARA Interiors Ltd | Professional & scientific | 2020 |
| Arab Africa Cargo Ltd | Administrative & support | 2016 |
| Arab African Board for Integration and Development CIC | Education | 2022 |
| Arabella & Partners Limited | Hospitality | 2022 |
| Arabia Limited | Administrative & support | 2018 |
| Arabic Islamic Centre Limited | Education | 2024 |
| Arabica Coffee Limited | Hospitality | 2015 |
| Aradhya Solution Ltd | Information & communication | 2013 |
| Aragon Classic Limited | Real estate | 2013 |
| Aragon House Limited | Hospitality | 2005 |
| Aram Consultants Limited | Financial services | 2023 |
| Arama Trading Limited | Wholesale & retail | 2022 |
| Aramanth Services Limited | Real estate | 2017 |
| Aran Consultancy Ltd | Professional & scientific | 2010 |
| Aran Property Consultants Limited | Professional & scientific | 2010 |
| Arana Holdings Limited | Real estate | 2018 |
| Arani Limited | Transport & logistics | 2019 |
| Aranyani Lifestyle Limited | Wholesale & retail | 2021 |
| Ararat Restorative Limited | Health & social care | 2024 |
| Arasan United Limited | Wholesale & retail | 2025 |
| Arash & Co Films Ltd | Information & communication | 2023 |
| Arav P Limited | Transport & logistics | 2013 |
| ARB Limited | Professional & scientific | 2006 |
| Arba Development Studios UK Limited | Administrative & support | 2016 |
| Arbib Productions Limited | Information & communication | 2018 |
| Arbiter Holding Ltd | Financial services | 2026 |
| Arbor House RTM Company Limited | Households | 2020 |
| Arbotech Ltd | Construction | 2023 |
| Arbourthorne Limited | Wholesale & retail | 2019 |
| ARC BR Limited | Construction | 2023 |
| ARC CP Ltd | Construction | 2025 |
| ARC Financial Services Ltd | Administrative & support | 1986 |
| ARC Media Works Ltd | Professional & scientific | 2022 |
| ARC Realty London Ltd | Real estate | 2025 |
| ARC SB 2 Limited | Construction | 2024 |
| ARC SB 3 Ltd | Construction | 2026 |
| ARC Studio Works Ltd | Information & communication | 2024 |
| ARC Writing and Language Services Limited | Professional & scientific | 2018 |
| Arcade Management Limited | Real estate | 2022 |
| Arcadia Build & Landscape Ltd | Construction | 2026 |
| Arcari Investments Limited | Real estate | 2020 |
| Arcest Limited | Professional & scientific | 2015 |
| Arch & Locks Ltd | Other services | 2024 |
| Arch Estates London Ltd | Real estate | 2020 |
| Arch Lucid Ltd | Professional & scientific | 2021 |
| Arch Struct Ltd | Construction | 2019 |
| Archana Menon Marketing Solutions Ltd | Professional & scientific | 2024 |
| Archglebe Ltd | Other services | 2001 |
| Archipel Technology Limited | Information & communication | 2015 |
| Archisan Ltd | Professional & scientific | 2020 |
| Architec Solutions Limited | Information & communication | 2013 |
| Architecture Initiative Limited | Professional & scientific | 2007 |
| Archive Design Limited | Professional & scientific | 2026 |
| Archmore Care Services Ltd | Health & social care | 2013 |
| Archo Ltd | Construction | 2026 |
| Arclucid Ltd | Information & communication | 2026 |
| Arcmead Limited | Information & communication | 2017 |
| Arcreaa Limited | Professional & scientific | 2020 |
| Arcs Automotive Limited | Extraterritorial | 2016 |
| ARD Paving Stones Limited | Construction | 2023 |
| Ardeleleanu Ltd | Construction | 2020 |
| Arden Building Consultancy Limited | Professional & scientific | 2018 |
| Arden House Care Home Limited | Health & social care | 2026 |
| Arden REP & Comms Consultancy Limited | Professional & scientific | 2023 |
| Ardencray Ltd | Health & social care | 2004 |
| Ardent Security Limited | Construction | 1991 |
| Ardent Source Ltd | Wholesale & retail | 2024 |
| Ardfield Engineering Limited | Other services | 2019 |
| Ardh Ventures Ltd | Real estate | 2026 |
| Ardourtech Consulting Ltd | Information & communication | 2023 |
| ARE WE Nearly There YET? Ltd | Professional & scientific | 2012 |
| Area Properties Limited | Real estate | 1948 |
| Area Screen Printers Limited | Other services | 2011 |
| Arebys Skills Ltd | Construction | 2017 |
| Areeva Healthcare Ltd | Health & social care | 2023 |
| Arekal Ltd | Information & communication | 2024 |
| Ares Associates Limited | Administrative & support | 2010 |
| Arete Consultants Limited | Information & communication | 2013 |
| Arete Process Intelligence Limited | Information & communication | 2026 |
| ARG Group Ltd | Construction | 2020 |
| Arga Investments Limited | Financial services | 2017 |
| Argent Partnership Administration Ltd | Administrative & support | 2017 |
| Argent Partnership Limited | Professional & scientific | 2014 |
| Argento-Palladio RTM Company Limited | Households | 2014 |
| Argo Sailing Ltd | Transport & logistics | 2025 |
| Argon Innovations Ltd | Information & communication | 2015 |
| Argoncillo Design Limited | Professional & scientific | 2018 |
| Argyle House Property Development Limited | Construction | 2015 |