| Aurora Surface Renewal Ltd | Administrative & support | 2025 |
| Auroraweb Collective Ltd | Information & communication | 2026 |
| Aurumguard Protection Limited | Administrative & support | 2026 |
| Ausdiagnostics UK Limited | Manufacturing | 2013 |
| Auspicious Property Management Ltd | Financial services | 2020 |
| Auston Design Limited | Professional & scientific | 2009 |
| Autism ABA Ltd | Health & social care | 2020 |
| Auto 7 Centre Ltd | Wholesale & retail | 2017 |
| Auto Claim Repair LAB Ltd | Wholesale & retail | 2025 |
| Auto Evolution Limited | Wholesale & retail | 2020 |
| Auto Reservation Plus Limited | Administrative & support | 2004 |
| Autobody Corrections Ltd | Wholesale & retail | 2022 |
| Autocase Limited | Information & communication | 2019 |
| Autodevotion Limited | Wholesale & retail | 1959 |
| Autofutura Holdings Limited | Financial services | 2009 |
| Autofutura Limited | Information & communication | 2002 |
| Autokora Ltd | Wholesale & retail | 2026 |
| Automated Controls (UK) Limited | Manufacturing | 1993 |
| Automatic Driving Lessons Ltd | Education | 2022 |
| Automotive Chris Ltd | Wholesale & retail | 2024 |
| Automotive Marketing Solutions Limited | Administrative & support | 2015 |
| Automotive Transformation Group Limited | Information & communication | 1999 |
| Autotransform Limited | Wholesale & retail | 2014 |
| Autovogue Motor Company Ltd | Wholesale & retail | 2019 |
| AV Technology Solutions Ltd | Professional & scientific | 2017 |
| AVA Grab Limited | Transport & logistics | 2004 |
| Avaio Ltd | Information & communication | 2008 |
| Avalanche Health Ltd | Administrative & support | 2025 |
| Avalanche Sports Marketing Limited | Wholesale & retail | 2010 |
| Avana Sharvi & Adrita Paul Ltd | Health & social care | 2023 |
| Avangard Group Limited | Administrative & support | 2024 |
| Avante (Coxheath) Management Limited | Households | 2007 |
| Avatar Consultancy (Kent) Ltd | Real estate | 2011 |
| Aventus Property Services Limited | Construction | 2024 |
| Avenue Entertainment Limited | Arts & recreation | 2016 |
| Aves Marine Limited | Manufacturing | 2019 |
| Aveverywhere Limited | Extraterritorial | 2024 |
| Avexorix Ltd | Transport & logistics | 2026 |
| Avicom Britania Limited | Financial services | 2009 |
| AVO Energy Advisory Ltd | Professional & scientific | 2024 |
| Avocet Northern Capital Holdings Ltd | Professional & scientific | 2016 |
| Avocet Northern Capital Management Ltd | Professional & scientific | 2016 |
| Avondale Building Company Ltd | Construction | 2015 |
| Avuc Services Limited | Information & communication | 2025 |
| Avviso Media Limited | Information & communication | 2014 |
| AW Clinical Services Ltd | Health & social care | 2025 |
| AWD Air Conditioning Ltd | Energy | 2015 |
| Awizness Business Consulting and Training Ltd | Professional & scientific | 2025 |
| Awlin Beauty Ltd | Health & social care | 2026 |
| AWR Property Solutions Limited | Real estate | 2025 |
| Axes Investments Limited | Financial services | 2012 |
| Axial Blue Ltd | Professional & scientific | 2019 |
| Axius Water European Holdings Limited | Professional & scientific | 2011 |
| Ayan Transport Ltd | Transport & logistics | 2020 |
| Ayleen&Edan Limited | Transport & logistics | 2018 |
| Aylesbury Studios Limited | Manufacturing | 2013 |
| Aylesford Car Wash Limited | Administrative & support | 2015 |
| Aylesford Vehicle Repairs Ltd | Wholesale & retail | 2024 |
| Ayobid Healtcare Limited | Health & social care | 2025 |
| Ayshella Ltd | Financial services | 2013 |
| AYT Developments Ltd | Real estate | 2018 |
| AZ Brothers Ltd | Hospitality | 2023 |
| Azof Creatives Limited | Information & communication | 2008 |
| Ação Suave Heat Glaze Systems Ltd | Construction | 2024 |
| B & B Components Cars Limited | Real estate | 2004 |
| B & B Property Innovations Ltd | Real estate | 2022 |
| B & I Express Limited | Transport & logistics | 2025 |
| B & M Concrete Products Limited | Wholesale & retail | 2003 |
| B & M Hurst Electrical Holdings Limited | Construction | 2018 |
| B & P Finance Consultants Limited | Financial services | 2002 |
| B & R Roofing Limited | Construction | 2015 |
| B & W Containers Limited | Construction | 1980 |
| B & Y 1970 Limited | Transport & logistics | 2024 |
| B Humphrey & Associates Ltd | Professional & scientific | 2022 |
| B J Rice & Associates LLP | | 2014 |
| B JET Interiors Ltd | Administrative & support | 2007 |
| B Lockyer Heating & Plumbing Limited | Construction | 2002 |
| B R Siggins Ltd | Real estate | 2017 |
| B&B Charcoalgrill Ltd | Hospitality | 2025 |
| B&B Drainage Solutions Ltd | Water & waste | 2023 |
| B&H Roofing Limited | Construction | 2009 |
| B&P Commercial Vehicle Wash Ltd | Administrative & support | 2021 |
| B.E. Ready Services Ltd | Transport & logistics | 2021 |
| B.G. Motors Limited | Wholesale & retail | 2018 |
| B.S.L Training Ltd | Education | 2014 |
| B.T. Interiors Ltd | Construction | 2012 |
| B.T.E. Trading Ltd | Wholesale & retail | 2019 |
| B.T.S. Transport Ltd | Transport & logistics | 2025 |
| B2B Homes Limited | Real estate | 2012 |
| B2R Health Coaching Limited | Health & social care | 2024 |
| B4B Trade and Marketing Ltd | Wholesale & retail | 2024 |
| BA BA BER Van Ltd | Other services | 2025 |
| BA Growth Consultants Ltd | Administrative & support | 2020 |
| Babadi Engineering Services Limited | Professional & scientific | 2025 |
| Babos Food Ltd | Hospitality | 2014 |
| Babos Kebab and Pizza Limited | Hospitality | 2022 |
| Baby About Limited | Wholesale & retail | 2023 |
| Baby Jones Ltd | Wholesale & retail | 2023 |
| Back for Good Communications Ltd | Information & communication | 2019 |
| Back Street Stays Ltd | Hospitality | 2026 |