| APL Fincorp Advisory Ltd | Real estate | 2008 |
| APM Solicitors Ltd | Professional & scientific | 2022 |
| Apollo Management Services Ltd | Real estate | 2017 |
| Apothecreed Ltd | Wholesale & retail | 2024 |
| App BI Solutions Ltd | Information & communication | 2014 |
| Appleberry Foods Limited | Wholesale & retail | 2007 |
| Appleberry Properties Ltd | Real estate | 2021 |
| Applique Lights Ltd | Wholesale & retail | 2025 |
| Appstech Solutions Limited | Information & communication | 2008 |
| Appvocado Ltd | Information & communication | 2017 |
| APS Asian Clean Express Limited | Administrative & support | 2024 |
| APX Ecomm Ltd | Wholesale & retail | 2024 |
| Aqqua Hair & Beauty Ltd | Other services | 2009 |
| Aqua Domestic & Commercial Plumbing & Heating Services Limited | Construction | 2002 |
| Aqua Lessons Limited | Education | 2017 |
| Aquarius Archery Club | Arts & recreation | 2018 |
| Aquarius Direct Limited | Wholesale & retail | 2019 |
| AR Physiocare PVT Ltd | Health & social care | 2024 |
| ARA M&E Services Ltd | Construction | 2019 |
| Arbi Properties Limited | Construction | 2018 |
| Arbor Agriculture Limited | Agriculture & fishing | 2017 |
| Arbour Court Management Ltd | Administrative & support | 2014 |
| Arbour Court Property Company Limited | Financial services | 2014 |
| Arcadegeek Ltd | Information & communication | 2011 |
| Arcas Properties Ltd | Real estate | 2015 |
| Arcas Properties Management Services Limited | Real estate | 2016 |
| Archetype Creative Consultancy Ltd | Administrative & support | 2015 |
| Archs Homes Ltd | Real estate | 2023 |
| Archstar Developments Limited | Construction | 2023 |
| Archway Accountants Ltd | Professional & scientific | 2023 |
| Archway Talent Solutions Ltd | Health & social care | 2020 |
| Arcturus Property Services Ltd | Construction | 2007 |
| Ardda Ltd | Construction | 2022 |
| Ardent Fieldwork Ltd | Administrative & support | 2013 |
| Ardent Investments Limited | Real estate | 2024 |
| Ardrahan Hire Ltd | Administrative & support | 2020 |
| Arena for Self Realization Ltd | Education | 2008 |
| Aretai LLP | | 2016 |
| ARF Marketing Ltd | Wholesale & retail | 2025 |
| Arfara Limited | Real estate | 2025 |
| Argo Innovation Ltd | Financial services | 2023 |
| Argos Mobility Limited | Professional & scientific | 2024 |
| Aria Events London Ltd | Hospitality | 2022 |
| Aria Intelligence Ltd | Wholesale & retail | 2023 |
| Arian Group Ltd | Construction | 2022 |
| Arihc Ltd | Construction | 2021 |
| Arilian Homes 2 Ltd | Real estate | 2017 |
| Aristocrat Fashion Limited | Wholesale & retail | 2019 |
| ARK Business Solutions Ltd | Professional & scientific | 2009 |
| ARK International LDN Ltd | Construction | 2019 |
| ARK IT Services & Resources Limited | Professional & scientific | 2024 |
| ARK World Travel Limited | Administrative & support | 2003 |
| Arkip Properties Ltd | Real estate | 2022 |
| Arks Investments Ltd | Real estate | 2015 |
| Arks Ventures Ltd | Professional & scientific | 2013 |
| Arman Enterprise PVT Ltd | Wholesale & retail | 2025 |
| Armand Groundworks and Paving Ltd | Construction | 2009 |
| ARN Liver Limited | Health & social care | 2025 |
| Arniss Limited | Professional & scientific | 2015 |
| Arnl Limited | Mining & quarrying | 2011 |
| Arrow Workforce International Limited | Transport & logistics | 2023 |
| Arrowcart Ltd | Wholesale & retail | 2026 |
| Arsh Creatives Ltd | Professional & scientific | 2021 |
| Art Classes in RYE Limited | Arts & recreation | 2016 |
| Art Focus Investments Limited | Wholesale & retail | 2019 |
| Art Rituals Limited | Arts & recreation | 2025 |
| Artam Estates Ltd | Real estate | 2021 |
| Artemis Management Limited | Real estate | 2025 |
| Artemis Olive Ltd | Wholesale & retail | 2019 |
| Artemis Supplies Limited | Wholesale & retail | 2025 |
| Artglade Associates Ltd | Professional & scientific | 2004 |
| Arthur Robotics Ltd | Professional & scientific | 2025 |
| Arthur Samuel Financial Services Limited | Financial services | 1977 |
| Artkulture Limited | Arts & recreation | 2021 |
| Artplinths Limited | Administrative & support | 2010 |
| Arts Hub UK Limited | Information & communication | 2002 |
| Arts Matrix Academy Limited | Education | 2017 |
| Aruhi Group Limited | Financial services | 2026 |
| Arundel International Limited | Professional & scientific | 2021 |
| Arundel Media Limited | Professional & scientific | 2013 |
| ARY Transport Ltd | Transport & logistics | 2025 |
| Aryan Properties Ltd | Real estate | 2014 |
| Arys Properties Limited | Real estate | 2024 |
| AS Ground Rent Investments Ltd | Real estate | 2007 |
| AS Ground Rent Investments Two Limited | Real estate | 2008 |
| AS Kerai Properties Ltd | Real estate | 2021 |
| AS YOU Like IT Building Services Brighton Ltd | Construction | 2019 |
| AS YOU Like IT Building Services Ltd | Construction | 2014 |
| AS YOU Like IT Maintenance Ltd | Construction | 2018 |
| ASA Valuations Ltd | Administrative & support | 2005 |
| Asas Holdings Limited | Real estate | 2015 |
| Ascot Barn Accountants Limited | Professional & scientific | 2025 |
| Ascot Place Freeholders Ltd | Real estate | 2019 |
| Ascot Traders Ltd | Real estate | 2021 |
| ASH Accountax Ltd | Professional & scientific | 2026 |
| ASH Brothers Limited | Real estate | 2017 |
| ASH Shah Consulting Ltd | Professional & scientific | 2024 |
| Asha the Traders Ltd | Information & communication | 2022 |
| Asha Valera Investments Limited | Real estate | 2025 |
| Ashbourne Property Consultants Ltd | Real estate | 2025 |