| AFA 2023 Ltd | Construction | 2023 |
| Afcc Limited | Health & social care | 2009 |
| Afcc Properties Limited | Real estate | 2014 |
| Affiliate IP Limited | Professional & scientific | 2016 |
| Affordable Accountants Ltd | Professional & scientific | 2021 |
| Affordable Petcare in Your Home Ltd | Professional & scientific | 2024 |
| Afix Limited | Construction | 2021 |
| Afordable Homes Ltd | Real estate | 2023 |
| Africa Star KIN Ltd | Administrative & support | 2019 |
| African Destinations 4 U Ltd | Information & communication | 2007 |
| African Supplies Ltd | Extraterritorial | 2025 |
| Afro Oasis Ltd | Wholesale & retail | 2025 |
| Afrofood House Company Ltd | Hospitality | 2026 |
| Afrohop London Entertainment Ltd | Arts & recreation | 2025 |
| Afzmak Ltd | Professional & scientific | 2024 |
| AG (Glendevon) Limited | Financial services | 2019 |
| AG (Moffat) Limited | Financial services | 2019 |
| AG Holiday Parks Lender Limited | Financial services | 2018 |
| AG Holiday Parks UK Limited | Financial services | 2017 |
| AG Newperran Limited | Financial services | 2018 |
| AG Newquay Limited | Hospitality | 2013 |
| AG Quick Service Limited | Manufacturing | 2011 |
| AG Refurbishment Ltd | Construction | 2013 |
| AG Retallack Limited | Hospitality | 2018 |
| AG Swanage Limited | Real estate | 2019 |
| AG Swanage Property Limited | Real estate | 2019 |
| Agbesanwa Asset Management Limited | Professional & scientific | 2022 |
| AGC Rentals Limited | Real estate | 2020 |
| AGD Electrical Contractors Ltd | Construction | 2019 |
| AGE UK Dacorum | Health & social care | 2003 |
| Agentix Global Ltd | Administrative & support | 2024 |
| Agile Savy Ltd | Information & communication | 2022 |
| Agilis Search Ltd | Administrative & support | 2017 |
| AGL Transport Ltd | Transport & logistics | 2021 |
| AGM Electrical Contractors Limited | Construction | 2019 |
| Agmk Holdings Ltd | Financial services | 2025 |
| Agmk Investments Limited | Financial services | 2018 |
| AH Construction & Domestics Ltd | Construction | 2018 |
| AH Lettings Ltd | Households | 2016 |
| AHA Developments (Hillside) Limited | Construction | 2024 |
| Ahanix Web Design Limited | Information & communication | 2026 |
| Ahead Tuition Limited | Education | 2022 |
| Ahmati Construction Ltd | Construction | 2026 |
| AI Equity Investments Ltd | Information & communication | 2023 |
| Aiam Logistics Limited | Transport & logistics | 2024 |
| Aichi Homes Ltd | Real estate | 2017 |
| AIM High Virtual Solutions Ltd | Administrative & support | 2025 |
| Aimact Ltd | Wholesale & retail | 2018 |
| Aimwood Installation and Testing Ltd | Manufacturing | 2013 |
| Ainsley Court Management Company Limited | Households | 1995 |
| Aion CFO Services Ltd | Professional & scientific | 2026 |
| Air Conditioning London Limited | Construction | 2014 |
| Aircraft Braking Systems Europe Limited | Extraterritorial | 1980 |
| Airies Gymnastics Club Ltd | Arts & recreation | 2018 |
| Airline Services Limited | Administrative & support | 2003 |
| Airports Made Easy Limited | Administrative & support | 2014 |
| Airsalon Limited | Other services | 2013 |
| Aistudio.London Limited | Information & communication | 2026 |
| AJ Electrical (Herts) Contractors Limited | Construction | 2010 |
| AJ Insight Consultancy Ltd | Professional & scientific | 2025 |
| AJ Oliver Transport Ltd | Transport & logistics | 2026 |
| AJ Pelley Ltd | Professional & scientific | 2022 |
| Ajay W.A. Management Limited | Construction | 2016 |
| AJB Plastering & Drylining Ltd | Construction | 2026 |
| Ajenas Nexus Ltd | Real estate | 2026 |
| AJH Tree Services Ltd | Administrative & support | 2026 |
| AJP 2020 Limited | Construction | 2020 |
| AJP Air Conditioning Limited | Manufacturing | 2023 |
| AJR Rigging Ltd | Construction | 2019 |
| AJS Propco Limited | Real estate | 2015 |
| Ajsd Group Limited | Professional & scientific | 2017 |
| AK Bees Ltd | Information & communication | 2022 |
| AK Konsult Ltd | Professional & scientific | 2026 |
| AK Mark Trading Limited | Other services | 2016 |
| AK. Parrish Ltd | Administrative & support | 2018 |
| AKA Properties Solutions Ltd | Construction | 2025 |
| AKA Services Solutions Limited | Wholesale & retail | 2023 |
| Akaash Hans Ltd | Financial services | 2018 |
| Akad Ltd | Real estate | 2026 |
| AKC of Hertfordshire Limited | Wholesale & retail | 2011 |
| Akce Ltd | Hospitality | 2025 |
| Akcine Bendrove Bankas "Snoras" | | 2008 |
| Akers Removals Ltd | Transport & logistics | 2018 |
| Akhaney Ltd | Wholesale & retail | 2024 |
| Akhyaal Ltd | Manufacturing | 2026 |
| AKI Build Ltd | Construction | 2023 |
| AKI Design Ltd | Professional & scientific | 2025 |
| Aklass Solutions Ltd | Administrative & support | 2024 |
| Akram & Co Wealth Management Ltd | Extraterritorial | 2022 |
| Akram Properties Limited | Real estate | 2018 |
| AL Qayyum Transport Limited | Transport & logistics | 2024 |
| Al-Uk Learning Ltd | Education | 2017 |
| Alacryon Ltd | Information & communication | 2025 |
| Alam Pharma Ltd | Wholesale & retail | 2022 |
| Alastair Ingram Motor Engineering Limited | Wholesale & retail | 2024 |
| Albacore Accounting Limited | Professional & scientific | 2009 |
| Alban City Plumbing & Heating Limited | Construction | 2018 |
| Alban Limited | Administrative & support | 2016 |
| Alban Pet Supplies Limited | Manufacturing | 2018 |
| Albani Industries Limited | Real estate | 2017 |