| Angel Scaffolding Group Ltd | Construction | 2021 |
| Angel Tribes Quality Healthcare Solutions Limited | Public administration | 2025 |
| Angela Photography Ltd | Professional & scientific | 2026 |
| Angela&Co Limited | Professional & scientific | 2025 |
| Angelz Care Limited | Health & social care | 2018 |
| Anghelus Transport Ltd | Transport & logistics | 2018 |
| Angles Solutions PVT Limited | Professional & scientific | 2013 |
| Anglo Asiatic Arts and Heritage Alliance | Arts & recreation | 2016 |
| Anicia Motor Company Limited | Wholesale & retail | 2024 |
| Anila Enterprises Ltd | Transport & logistics | 2015 |
| Anitas Independent Social Work Ltd | Health & social care | 2025 |
| Anka 1 Properties Limited | Real estate | 2020 |
| Ankit PAL Limited | Construction | 2024 |
| Anmol Construction Ltd | Construction | 2014 |
| Anmol Real Estate Ltd | Real estate | 2021 |
| Anna Bradley Company Ltd | Transport & logistics | 2018 |
| Anna Future Solutions Ltd | Transport & logistics | 2017 |
| Annette & Eddie Ltd | Health & social care | 2023 |
| Annisse Limited | Other services | 2010 |
| Anokhi Threads Ltd | Wholesale & retail | 2024 |
| ANR Haulage Ltd | Transport & logistics | 2020 |
| ANR Tyres Limited | Manufacturing | 2010 |
| Anthonio Services Ltd | Transport & logistics | 2016 |
| Antonella Burgio Ltd | Health & social care | 2012 |
| Antony Owens Limited | Wholesale & retail | 2017 |
| Anushay Admire Enterprises Ltd | Wholesale & retail | 2023 |
| Anya Properties Limited | Real estate | 2020 |
| Anydany Ltd | Transport & logistics | 2013 |
| AO Management Ltd | Arts & recreation | 2018 |
| AO System Accounting Ltd | Professional & scientific | 2019 |
| AOA Tech Ltd | Information & communication | 2014 |
| Aoahomes Ltd | Real estate | 2024 |
| Aodconsultancy Limited | Information & communication | 2022 |
| Aodiro Consulting Ltd | Professional & scientific | 2022 |
| Aoja Construction Ltd | Construction | 2025 |
| Aolat Integrated Ventures Limited | Wholesale & retail | 2023 |
| Aonm Limited | Real estate | 2022 |
| AP Flooring Ltd | Construction | 2018 |
| AP Infinity Ltd | Real estate | 2025 |
| AP Landscaping & Paving Ltd | Administrative & support | 2025 |
| AP Sparky Ltd | Construction | 2021 |
| AP Support Ltd | Administrative & support | 2018 |
| AP Window Cleaning Support Services Ltd | Administrative & support | 2024 |
| Apcal Consulting Ltd | Professional & scientific | 2012 |
| Apcr Transport Services Ltd | Transport & logistics | 2016 |
| Apex Haus Ltd | Real estate | 2025 |
| Apex QS Limited | Professional & scientific | 2026 |
| Apex Smart Business Solutions Ltd | Professional & scientific | 2025 |
| Apexcare Property Services Limited | Real estate | 2025 |
| Apisma Solutions Limited | Administrative & support | 2021 |
| APJ Works Ltd | Wholesale & retail | 2018 |
| Apodecor Ltd | Construction | 2019 |
| Apogee Traders Ltd | Wholesale & retail | 2019 |
| App Logistik Ltd | Transport & logistics | 2017 |
| App Team Ltd | Construction | 2022 |
| Applemint Properties Limited | Real estate | 2021 |
| Aprilis Group Holdings Ltd | Financial services | 2024 |
| Aqtb Consulting Limited | Information & communication | 2025 |
| Aqua Childrens' Homes Ltd | Health & social care | 2023 |
| Aqua Robson Special Needs Alternative Provision Ltd | Education | 2026 |
| Aqua Sealants Ltd | Construction | 2024 |
| Aqua Term Ltd | Construction | 2018 |
| Aquagem Investments UK Ltd | Extraterritorial | 2022 |
| Aquaguard Ltd | Construction | 2025 |
| Aquarius Solutions Ltd | Administrative & support | 2015 |
| Aquarius Technology Services SL Ltd. | Professional & scientific | 2010 |
| AR Contractors Ltd | Construction | 2013 |
| AR Creativity Ltd | Construction | 2025 |
| ARA Corporations Limited | Real estate | 2018 |
| Arava Search Ltd | Administrative & support | 2024 |
| Arberry Holdings Limited | Real estate | 2019 |
| Arbi Construction Ltd | Construction | 2026 |
| ARC & Sons Developments UK Limited | Construction | 2025 |
| ARC Haulage Ltd | Transport & logistics | 2025 |
| Ardas Solutions Ltd | Construction | 2014 |
| Ardent Accountancy Services Ltd | Professional & scientific | 2018 |
| Ardent Financial Services Limited | Professional & scientific | 2016 |
| Ardent Payroll Limited | Administrative & support | 2019 |
| Arfy Business Ltd | Wholesale & retail | 2021 |
| Argent Street "C" Management Limited | Households | 1987 |
| Argent Street "F" Management Company Limited | Real estate | 1987 |
| Argent Street "H" Management Company Limited | Households | 1987 |
| Argent Street "J" Management Company Limited | Households | 1987 |
| Arian Visual Solutions Limited | Manufacturing | 2012 |
| Arif Ferdous Ltd | Wholesale & retail | 2019 |
| Arise Property Group Ltd | Real estate | 2025 |
| ARK Drylining Limited | Construction | 2014 |
| ARK of the Covenant Prayer and Worship Tabernacle | Other services | 2008 |
| ARK Project Partners Ltd | Information & communication | 2013 |
| ARK Software Services Limited | Information & communication | 2018 |
| Arka Group Holdings Limited | Professional & scientific | 2025 |
| Arkasssa Ltd | Construction | 2024 |
| Arkenstone AG Limited | Professional & scientific | 2010 |
| Armant Consultancy Limited | Construction | 2018 |
| Armour Security Group (UK) Ltd | Administrative & support | 2020 |
| Armourfast (London) Limited | Manufacturing | 2014 |
| Arms Builders Ltd | Construction | 2022 |
| Arnica Recovery Ltd | Manufacturing | 2020 |
| Arrahim Developments Ltd | Construction | 2026 |
| Art Cars Essex Ltd | Wholesale & retail | 2018 |