| Aeromecha Ltd | Professional & scientific | 2011 |
| Aeroports Marketing Services Limited | Administrative & support | 2001 |
| Aeroprop (South West) Limited | Manufacturing | 2018 |
| Aerospace & Airworthiness Consultancy Enterprises Limited | Professional & scientific | 1997 |
| Aerospace Industry.Com Ltd | Manufacturing | 2014 |
| Aerospace KMF Limited | Manufacturing | 2025 |
| Aerospike Games Ltd | Manufacturing | 2025 |
| Aeroteck Limited | Professional & scientific | 2012 |
| Aerotek Design Limited | Administrative & support | 2008 |
| Aeroto Ltd | Education | 2020 |
| Aery Limited | Wholesale & retail | 2019 |
| AES Ballylumford Holdings Limited | Financial services | 2010 |
| AES Barry Limited | Professional & scientific | 1995 |
| AES Barry Operations Limited | Financial services | 1996 |
| AES Electric Ltd | Financial services | 1988 |
| AES Horizons Investments Limited | Financial services | 1992 |
| AES Overseas Holdings Limited | Financial services | 2008 |
| AES Signs Limited | Administrative & support | 2005 |
| AES TEP Power II Investments Limited | Financial services | 1926 |
| AES UK Datacenter Services Limited | Professional & scientific | 1999 |
| AES UK Holdings Ltd | Financial services | 1997 |
| AES Wind Generation Limited | Financial services | 2000 |
| Aesthetic Beauty Training Ltd | Wholesale & retail | 2020 |
| Aesthetic Dental Laboratory Limited | Manufacturing | 2010 |
| Aesthetic Purposes Only Ltd | Extraterritorial | 2025 |
| Aesthetics at 22 Ltd | Other services | 2025 |
| Aesthetics Bristol by Gulshan Limited | Other services | 2019 |
| Aesthetics by Kate Limited | Other services | 2024 |
| Aesthetics. YOU. Limited | Other services | 2022 |
| Aesthetiq Insight Ltd | Information & communication | 2025 |
| AET Consulting Services Ltd | Professional & scientific | 2020 |
| Aether Investment (UK) Limited | Wholesale & retail | 2024 |
| Aether Research Limited | Professional & scientific | 2026 |
| Aether Sauna Limited | Professional & scientific | 2024 |
| Aetos Ithaki Ltd | Wholesale & retail | 2021 |
| Aeuk Battery Project I Ltd | Manufacturing | 2022 |
| Aeuk Battery Project II Ltd | Manufacturing | 2022 |
| Aeuk Battery Project III Ltd | Manufacturing | 2022 |
| Aeuk Battery Project IV Ltd | Manufacturing | 2022 |
| Aeuk Battery Project IX Ltd | Energy | 2022 |
| Aeuk Battery Project V Ltd | Energy | 2022 |
| Aeuk Battery Project VI Ltd | Energy | 2022 |
| Aeuk Battery Project VII Ltd | Energy | 2022 |
| Aeuk Battery Project Viii Ltd | Energy | 2022 |
| Aeuk Battery Project X Ltd | Energy | 2023 |
| Aeuk Battery Project XI Ltd | Energy | 2023 |
| Aeuk Battery Project Xiii Ltd | Energy | 2023 |
| Aeuk Battery Project XIV Ltd | Energy | 2023 |
| Aeuk Battery Project XIX Ltd | Energy | 2023 |
| Aeuk Battery Project XV Ltd | Energy | 2023 |
| Aeuk Battery Project XVI Ltd | Energy | 2023 |
| Aeuk Battery Project Xvii Ltd | Energy | 2023 |
| Aeuk Battery Project Xviii Ltd | Energy | 2023 |
| Aeuk Battery Project XX Ltd | Energy | 2023 |
| Aeuk Battery Project XXI Ltd | Energy | 2023 |
| Aeuk Battery Project Xxiv Ltd | Energy | 2023 |
| Aeuk Battery Project Xxvii Ltd | Energy | 2023 |
| Aeuk Battery Project Xxxii Ltd | Energy | 2024 |
| Aeuk Battery Project Xxxv Ltd | Energy | 2024 |
| Aeuk Battery Project Xxxvi Ltd | Energy | 2024 |
| Aeuk DC Project I Ltd | Construction | 2024 |
| Aeuk DC Project II Ltd | Construction | 2024 |
| Aeuk DC Project III Ltd | Construction | 2024 |
| Aeuk Solar Project II Ltd | Energy | 2023 |
| Aeuk Solar Project III Ltd | Energy | 2023 |
| Aeuk Solar Project IV Ltd | Energy | 2023 |
| Aeuk Solar Project IX Ltd | Energy | 2023 |
| Aeuk Solar Project V Ltd | Energy | 2023 |
| Aeuk Solar Project VI Ltd | Energy | 2023 |
| Aeuk Solar Project VII Ltd | Energy | 2023 |
| Aeuk Solar Project Viii Ltd | Energy | 2023 |
| Aeuk Solar Project X Ltd | Energy | 2023 |
| Aeuk Solar Project XI Ltd | Energy | 2023 |
| Aeuk Solar Project XII Ltd | Energy | 2023 |
| Aeuk Solar Project XIV Ltd | Energy | 2023 |
| Aeuk Wind Project I Ltd | Energy | 2023 |
| Aeuk Wind Project II Ltd | Energy | 2023 |
| Aeuk Wind Project III Ltd | Energy | 2024 |
| Aeuk Wind Project IV Ltd | Energy | 2024 |
| Aeuk Wind Project V Ltd | Energy | 2024 |
| Aeuk Wind Project VI Ltd | Energy | 2024 |
| Aeuk Wind Project VII Ltd | Energy | 2024 |
| Aeuk Wind Project Viii Ltd | Energy | 2024 |
| Aevum Estate Protection Ltd | Professional & scientific | 2022 |
| AF Brickstore Ltd | Wholesale & retail | 2025 |
| AF Live Limited | Administrative & support | 2006 |
| AF Mobile Accessories Ltd | Wholesale & retail | 2019 |
| AF Sporting Events Ltd | Wholesale & retail | 2023 |
| Afan Valley Escapes Ltd | Hospitality | 2018 |
| AFB Driving School Ltd | Education | 2026 |
| AFB Marketing Limited | Professional & scientific | 2025 |
| AFB Partners Ltd | Education | 2025 |
| AFC Accountancy Services Limited | Extraterritorial | 2012 |
| AFC IT Solutions Limited | Information & communication | 2018 |
| Afcon Limited | Real estate | 2024 |
| AFE Holdings Limited | Hospitality | 2019 |
| Affinia Partnerships Limited | Professional & scientific | 2006 |
| Affinity Partnership Group Ltd | Administrative & support | 2019 |
| Affirmative Limited | Wholesale & retail | 2000 |
| Affix Signs Ltd. | Construction | 2022 |