| A-C VFX Ltd | Information & communication | 2026 |
| A-C Water Management Ltd | Water & waste | 2018 |
| A-C-T International Limited | Professional & scientific | 2016 |
| A-Check Aviation Ltd | Professional & scientific | 2023 |
| A-Class Heating Services Ltd | Construction | 2025 |
| A-Class Salon Limited | Health & social care | 2019 |
| A-Clean Ltd | Other services | 2014 |
| A-Clean Solutions Ltd | Administrative & support | 2025 |
| A-Cold-Wall* Limited | Administrative & support | 2016 |
| A-Commotion Limited | Information & communication | 2005 |
| A-Connect Solution (UK) Limited | Professional & scientific | 2009 |
| A-Core Services Ltd | Extraterritorial | 2008 |
| A-Cute Scrubs Ltd | Wholesale & retail | 2025 |
| A-D 34 Shooters Hill Road RTM Company Ltd | Households | 2023 |
| A-D Financial Limited | Wholesale & retail | 2012 |
| A-Did Marketing Limited | Professional & scientific | 2022 |
| A-Digital Works Ltd | Information & communication | 2023 |
| A-Fit : Anglo-French Interim Transition Limited | Professional & scientific | 2024 |
| A-Fix Orthopaedics Limited | Health & social care | 2005 |
| A-Form Construction Ltd | Construction | 2015 |
| A-Frame Futures Ltd | Professional & scientific | 2025 |
| A-Francés Ltd | Wholesale & retail | 2019 |
| A-Game Pubs & Bars Ltd | Hospitality | 2024 |
| A-Golden Key Construction Ltd | Construction | 2023 |
| A-Grill House Ltd | Hospitality | 2026 |
| A-Guard Robotics Limited | Administrative & support | 2025 |
| A-Hdw S.L. Ltd | Professional & scientific | 2018 |
| A-Holic Ltd | Hospitality | 2026 |
| A-House Investments Limited | Administrative & support | 2016 |
| A-Hr.Pro Ltd | Information & communication | 2026 |
| A-Infinity Limited | Information & communication | 2005 |
| A-J (London) Limited | Real estate | 2006 |
| A-J Building Group Ltd | Construction | 2016 |
| A-K Car Park Limited | Arts & recreation | 2013 |
| A-K-E Construction Ltd | Construction | 2014 |
| A-Kwart Cleaning Expert Ltd | Administrative & support | 2025 |
| A-Lab Solutions Limited | Information & communication | 2016 |
| A-Label Worldwide Records Ltd | Wholesale & retail | 2025 |
| A-Lash London Ltd | Wholesale & retail | 2023 |
| A-Lean Ltd | Construction | 2025 |
| A-Line Jewellery Ltd | Manufacturing | 2010 |
| A-List Film Production Pro Ltd | Information & communication | 2021 |
| A-List Management Limited | Administrative & support | 2013 |
| A-List Marketing Limited | Wholesale & retail | 2024 |
| A-List Studio Limited | Arts & recreation | 2024 |
| A-List Wardrobe Services Ltd | Wholesale & retail | 2025 |
| A-Luxe Ltd | Wholesale & retail | 2022 |
| A-Mac Steel Ltd | Construction | 2014 |
| A-Mama Ltd | Wholesale & retail | 2025 |
| A-Mart Global Ltd | Wholesale & retail | 2026 |
| A-Mix Concrete Ltd | Manufacturing | 2026 |
| A-Mnemonic Limited | Information & communication | 2013 |
| A-Muse Ltd | Information & communication | 2019 |
| A-N-S Design Limited | Other services | 2025 |
| A-Okdigital Ltd | Professional & scientific | 2026 |
| A-One Action Ltd | Administrative & support | 2021 |
| A-One Nails & Spa TN Ltd | Other services | 2018 |
| A-Paraiso Ltd | Other services | 2022 |
| A-Pearl UK Ltd | Wholesale & retail | 2026 |
| A-Plan Group Ltd | Financial services | 2014 |
| A-Plan Limited | Financial services | 1993 |
| A-Player AI Ltd | Information & communication | 2026 |
| A-Plot Ltd | Real estate | 2020 |
| A-Plus Clinic Ltd | Other services | 2024 |
| A-Plus Ideation Agency Ltd | Professional & scientific | 2017 |
| A-Plus Management Services Limited | Real estate | 2024 |
| A-Point Marketing Ltd | Financial services | 2018 |
| A-Poj Limited | Information & communication | 2000 |
| A-Project Design Limited | Professional & scientific | 2013 |
| A-Projects Ltd | Professional & scientific | 2008 |
| A-Rail Limited | Construction | 2018 |
| A-Roads Investments Limited | Professional & scientific | 2006 |
| A-Run Official Ltd | Wholesale & retail | 2022 |
| A-Scalewise Ltd | Wholesale & retail | 2025 |
| A-Side Consultancy Limited | Arts & recreation | 2005 |
| A-Side Ltd | Households | 2013 |
| A-Side Publishing Limited | Professional & scientific | 2001 |
| A-Sides Copywriting Limited | Professional & scientific | 2025 |
| A-Silk Ltd | Wholesale & retail | 2020 |
| A-Sin Creative Group Ltd | Professional & scientific | 2023 |
| A-Six Ventures Ltd | Financial services | 2023 |
| A-Smood Management Consulting Ltd | Professional & scientific | 2017 |
| A-Social-Life Ltd | Professional & scientific | 2024 |
| A-Sphere Insurance Software Limited | Information & communication | 2008 |
| A-Spire Consulting (UK) Limited | Real estate | 2005 |
| A-Squared (A2) Ltd | Professional & scientific | 2025 |
| A-Squared Consulting Limited | Information & communication | 2012 |
| A-Star Cleaning Care Limited | Other services | 2017 |
| A-Star Property Solutions Limited | Real estate | 2021 |
| A-Star Pupils Tuition Ltd | Administrative & support | 2021 |
| A-Star Tuitions PVT. Ltd | Education | 2018 |
| A-Star Tutorials Limited | Education | 2005 |
| A-Stars Business Ltd | Wholesale & retail | 2025 |
| A-Ster Makeup Limited | Other services | 2017 |
| A-Strat Advisory Limited | Professional & scientific | 2013 |
| A-Symetry Ltd | Construction | 2011 |
| A-Sync Recruitment Ltd | Administrative & support | 2025 |
| A-Tac Holdings Limited | Financial services | 2022 |
| A-Talents Limited | Administrative & support | 2020 |
| A-Talnt Company Ltd | Administrative & support | 2025 |