| Adrian Hague Ltd | Administrative & support | 2024 |
| Adrian Kapuscinski Limited | Administrative & support | 2014 |
| Adriana Construcion Ltd | Construction | 2025 |
| Adriannicolae Ltd | Transport & logistics | 2016 |
| Adriano 973 Ltd | Transport & logistics | 2019 |
| Adroit Tech Services Limited | Information & communication | 2024 |
| ADS + RK Limited | Wholesale & retail | 2002 |
| ADS Autos Groups Ltd | Wholesale & retail | 2026 |
| ADS Business Ltd | Wholesale & retail | 2016 |
| ADS River Park Homes Ltd | Construction | 2025 |
| ADS Sons Ltd | Wholesale & retail | 2025 |
| Adsen Moore Holding Co Ltd | Financial services | 2016 |
| Adsila Assets Limited | Real estate | 2018 |
| Adsluxe Ltd | Wholesale & retail | 2025 |
| Adura Solutions Limited | Professional & scientific | 2018 |
| Advance Consortium UK Ltd | Professional & scientific | 2021 |
| Advance Foam Limited | Real estate | 1983 |
| Advance Foam Products Limited | Extraterritorial | 1985 |
| Advance Marketing Services Ltd | Wholesale & retail | 2024 |
| Advanced Drains Ltd | Construction | 2008 |
| Advanced Hire Services Ltd | Administrative & support | 2024 |
| Advanced Insurance Centres Limited | Financial services | 2000 |
| Advanced Investment Management LLP | | 2007 |
| Advanced Marketing Consulting Limited | Professional & scientific | 2018 |
| Advanced Real Estate Limited | Real estate | 2021 |
| Advanced Solutions Consultants Limited | Professional & scientific | 2005 |
| Advanced Tech Services Ltd | Information & communication | 2026 |
| Advanced Thinking Ltd | Professional & scientific | 2024 |
| Advanced Utility Services Ltd | Water & waste | 2023 |
| Advanced Woodford Glazing Company Limited | Construction | 2006 |
| Advasol Management Ltd | Professional & scientific | 2003 |
| Adventx Ltd | Professional & scientific | 2023 |
| Adverdizesearch Ltd | Wholesale & retail | 2025 |
| Advertising and Digital Media Ltd | Professional & scientific | 2025 |
| Advertsignment Limited | Other services | 2023 |
| Advertstrify Limited | Wholesale & retail | 2025 |
| Advice Bureau Ltd | Professional & scientific | 2024 |
| Advice Direct Limited | Professional & scientific | 2023 |
| Advice Wise Solicitors Ltd | Professional & scientific | 2012 |
| Advisia Ukeig | | 2013 |
| Advision International Ltd | Real estate | 2022 |
| Advocacy for Green Energy (AGE) Limited | Information & communication | 2022 |
| Adworld Conferences Limited | Administrative & support | 2021 |
| ADY Joker Ltd | Transport & logistics | 2021 |
| Adyar Ananda Bhavan Sweets Snacks & Restaurant Limited | Hospitality | 2022 |
| Adyar River Holding Company Limited | Real estate | 2017 |
| Adyspeedtrans Limited | Transport & logistics | 2013 |
| Adzamu Ltd | Health & social care | 2023 |
| AE Civil Engineering Limited | Construction | 2023 |
| Ae&D Joinery Ltd | Construction | 2026 |
| AEA Rose Consulting Limited | Administrative & support | 2025 |
| AEB Consultancy Ltd | Information & communication | 2017 |
| Aecs Enterprise Ltd | Health & social care | 2023 |
| AEG Trans Ltd | Transport & logistics | 2020 |
| Aegis Prime Security Limited | Administrative & support | 2026 |
| Aegis Vanguard Ltd | Financial services | 2025 |
| Aeirfy Ltd | Wholesale & retail | 2024 |
| Aelius Makeovers London Ltd | Other services | 2026 |
| Aeliya Foods Ltd | Wholesale & retail | 2013 |
| Aelos Limited | Information & communication | 2008 |
| AEM Wealth and a Y U Ltd | Real estate | 2019 |
| Aemora Makeup Ltd | Wholesale & retail | 2024 |
| AEN Corporation Ltd | Wholesale & retail | 2020 |
| Aeon Electronic Protection Systems Ltd | Administrative & support | 1999 |
| Aeon Nursing Ltd | Administrative & support | 2018 |
| Aeos Holding Ltd | Real estate | 2025 |
| Aero Vista Solutions Ltd | Wholesale & retail | 2025 |
| Aeronox Limited | Professional & scientific | 2017 |
| AES Construction (Brickwork) Limited | Real estate | 2014 |
| AES Construction Services Limited | Construction | 2005 |
| Aesthetic Designs (U.K.) Ltd. | Professional & scientific | 2002 |
| Aesthetic Sense Limited | Health & social care | 2002 |
| Aesthetics by Mairaa Khan Ltd | Health & social care | 2025 |
| Aesthetics MD Limited | Other services | 2025 |
| Aetas Photogrpahy Limited | Professional & scientific | 2015 |
| Aetheria House Ltd | Wholesale & retail | 2025 |
| Aetherium Field Anchoring Limited | Information & communication | 2025 |
| Aeturnum Limited | Information & communication | 2021 |
| AEU Catering Ltd | Hospitality | 2024 |
| Aevitas Ventures Ltd | Construction | 2023 |
| Aevum Bespoke Ltd | Manufacturing | 2025 |
| Aevum Developments Ltd | Construction | 2020 |
| Aeyms Group Ltd | Manufacturing | 2023 |
| AF Appliances Limited | Wholesale & retail | 2018 |
| AF Electric Ltd | Construction | 2016 |
| AF House Ltd | Real estate | 2025 |
| AFA Trader's Limited | Wholesale & retail | 2024 |
| Afagad Ltd | Real estate | 2021 |
| Afam Optics Ltd | Health & social care | 2022 |
| Afaq Enterprises Ltd | Wholesale & retail | 2018 |
| Afarin Ltd | Education | 2022 |
| Affaf Accountants Limited | Professional & scientific | 2018 |
| Affitti Ltd | Real estate | 2023 |
| Affordable Community Catering and Services Limited | Other services | 2012 |
| Affordable Home Properties Ltd | Real estate | 2025 |
| Affordable Property Maintenance Ltd | Construction | 2023 |
| AFG Halal Food Ltd | Hospitality | 2023 |
| AFG Ilford Ltd | Wholesale & retail | 2022 |
| Afgbodyworkrepair Ltd | Wholesale & retail | 2019 |
| Afghan & Lebanese MIX Food Ltd | Hospitality | 2020 |