| Audit and Accounts Pro Limited | Professional & scientific | 2014 |
| Audley Walk (Management) Limited | Real estate | 1997 |
| Audleys Wood Hotel Limited | Hospitality | 2007 |
| Aurora Lifts Ltd | Manufacturing | 1990 |
| Austens Drive (Sevenoaks) Limited | Households | 2000 |
| Autev Ltd | Professional & scientific | 2005 |
| Authentique Wine Ltd | Wholesale & retail | 2025 |
| Authorised Representative Services Limited | Professional & scientific | 2017 |
| Auto Rematch Limited | Wholesale & retail | 2025 |
| Auto Windscreens Services Limited | Wholesale & retail | 2011 |
| Autobahn Beckenham Limited | Extraterritorial | 1985 |
| Autocraft (Kent) Limited | Wholesale & retail | 2009 |
| Autohoods Limited | Extraterritorial | 2007 |
| Automate Digital AI Ltd | Information & communication | 2025 |
| Automatic Actuarials Limited | Information & communication | 2020 |
| Automatic Systems Laboratories Limited | Extraterritorial | 2012 |
| Automobile Engineering Company Limited | Wholesale & retail | 2003 |
| Automotive Diagnostic Specialists Ltd. | Manufacturing | 2017 |
| AV Homeworks Limited | Wholesale & retail | 2012 |
| Avanti Corporate Partners LLP | | 2021 |
| Avborro Limited | Professional & scientific | 2022 |
| Avelar Solutions Ltd | Construction | 2021 |
| Avelene Interiors Limited | Wholesale & retail | 2018 |
| Aventti Strategic Partners LLP | | 2014 |
| Avenue Printing Limited | Manufacturing | 1991 |
| Averroes Baca Ltd. | Professional & scientific | 2015 |
| AVG Enterprises Limited | Extraterritorial | 2014 |
| Aviator Properties Ltd | Real estate | 2025 |
| Avinet Ltd | Information & communication | 2023 |
| Avion Europe Ltd | Administrative & support | 2012 |
| Avocet Business Consulting Limited | Professional & scientific | 2011 |
| Avocet Services Limited | Health & social care | 2004 |
| AW Corrosion Holdings Limited | Financial services | 2019 |
| AW Corrosion Solutions Limited | Administrative & support | 2012 |
| AW Structural Assessment Limited | Administrative & support | 2020 |
| Awamu | Other services | 2011 |
| AXE Asset Management Ltd | Financial services | 2022 |
| AXE Capital Limited | Financial services | 2022 |
| Axelle Van Haver Translations Ltd | Professional & scientific | 2022 |
| Axera Limited | Administrative & support | 2025 |
| Axicode Ltd. | Professional & scientific | 1997 |
| Axiora Capital Ltd | Professional & scientific | 2025 |
| Axle Engineering Ltd | Manufacturing | 2023 |
| Axten PR Ltd | Professional & scientific | 2017 |
| AY Communications Limited | Other services | 2015 |
| AY Infra and Energy Ltd | Professional & scientific | 2022 |
| AY Ventures Consulting Ltd | Professional & scientific | 2023 |
| Aych Holdings Limited | Real estate | 2023 |
| Aylesford Fire Protection Limited | Public administration | 2014 |
| Ayton Development Solutions Limited | Other services | 2015 |
| Azara Logic LLP | | 2012 |
| Aznew Ltd | Construction | 2024 |
| Aztech Group South East Ltd | Administrative & support | 2018 |
| Aztech Tree Services Ltd | Administrative & support | 2022 |
| Azzure Risk Consulting Ltd | Administrative & support | 2025 |
| Ação Suave Group Ltd | Construction | 2022 |
| B & R Installations Limited | Construction | 1985 |
| B and B Sports Ltd | Wholesale & retail | 2022 |
| B Ballin Ltd | Education | 2018 |
| B Block Lakeside Apartments RTM Company Limited | Households | 2025 |
| B K Resin Flooring Limited | Construction | 2011 |
| B Moore Property Ltd | Real estate | 2020 |
| B$B Limited | Arts & recreation | 2025 |
| B&B Scaffolding Ltd | Construction | 2025 |
| B.N.S. Electrical Services Ltd | Energy | 2007 |
| BA DUM Tish Ltd | Wholesale & retail | 2020 |
| Babes Brunch Ltd | Extraterritorial | 2024 |
| Babr Debt Recovery Limited | Administrative & support | 2006 |
| Babr Finance Limited | Professional & scientific | 2022 |
| Baby&More Limited | Wholesale & retail | 2011 |
| Babyworld Skin Care Ltd | Manufacturing | 2025 |
| Backup Security Ltd | Information & communication | 2026 |
| BAD Stitches Ltd | Wholesale & retail | 2026 |
| Badham Group Ltd | Financial services | 2026 |
| Bagginshire Ltd | Other services | 2023 |
| Bailbrook House Hotel (NO 2) Limited | Hospitality | 2012 |
| Bailbrook House Hotel Limited | Hospitality | 2012 |
| Bailey Ahmad Holdings Limited | Professional & scientific | 2009 |
| Bailey Ahmad Limited | Administrative & support | 2006 |
| Baines London Ltd | Wholesale & retail | 2025 |
| Balance Worldwide Limited | Wholesale & retail | 2010 |
| Balanced View Limited | Other services | 2016 |
| Balancyoga House LLP | | 2026 |
| Balaspook Limited | Real estate | 2025 |
| Balfour Limited | Construction | 1981 |
| Balladeer Records Ltd | Wholesale & retail | 2022 |
| Balldog Limited | Arts & recreation | 2021 |
| Balti Mosala UK Limited | Hospitality | 2024 |
| Balustrade and Balcony Suppliers and Installers Association | Other services | 2021 |
| Bambini Childcare Services Limited | Health & social care | 2026 |
| Bambotany Ltd | Manufacturing | 2025 |
| Banbicary LLP | | 2016 |
| Bang Boom Creative Limited | Information & communication | 2011 |
| Bang OUT of Order Productions Ltd | Information & communication | 2024 |
| Baniftec Limited | Information & communication | 1981 |
| Bankbuild Ltd | Information & communication | 2025 |
| Bankside Media Limited | Professional & scientific | 2001 |
| Banner Property Group Limited | Real estate | 2021 |
| Bantam Property Limited | Real estate | 2004 |
| Baobab Africa Opportunities Ltd | Health & social care | 2023 |