| Adart Advisory Ltd | Arts & recreation | 2024 |
| ADC Facilities Ltd | Real estate | 2026 |
| ADD a Room Ltd | Construction | 2016 |
| Adda Estates Ltd | Real estate | 2025 |
| Addison Social Housing Limited | Professional & scientific | 2004 |
| Addo Commercial Services Ltd | Professional & scientific | 2024 |
| ADE Electrical Services Limited | Construction | 2026 |
| Adeleja Ventures Ltd | Real estate | 2026 |
| Adeoshun Ltd | Construction | 2024 |
| Adesuyi Ventures Ltd | Wholesale & retail | 2024 |
| Adez Barbers & Beauty Hub Ltd | Other services | 2024 |
| ADF Power Ltd | Other services | 2024 |
| Adhocs Care Solutions Limited | Health & social care | 2017 |
| Adigreen Ltd | Professional & scientific | 2021 |
| Adiuja Ltd | Real estate | 2023 |
| ADJ Phils Management Limited | Professional & scientific | 2010 |
| Adjustit Limited | Construction | 2025 |
| Adkn Investment Ltd | Real estate | 2020 |
| Admiral Property Solutions Limited | Transport & logistics | 2016 |
| ADN Building Services Ltd | Construction | 2022 |
| Adom Ventures Limited | Extraterritorial | 2026 |
| Adore Outdoor Ltd | Professional & scientific | 2020 |
| ADP Action Limited | Administrative & support | 2022 |
| Adplan Software Limited | Information & communication | 2019 |
| ADR Challenge Ltd | Transport & logistics | 2015 |
| ADS Drilling and Sawing Ltd | Construction | 2023 |
| ADS Health Limited | Wholesale & retail | 2011 |
| Adsi (Holdings) Limited | Real estate | 2014 |
| Adsi Business Services Limited | Financial services | 2021 |
| Adsi Solutions Ltd | Information & communication | 2008 |
| Aduke Healthcare Agency Ltd | Health & social care | 2022 |
| ADV Property Services Ltd | Manufacturing | 2025 |
| Advance Logistic Limited | Transport & logistics | 2018 |
| Advance Sistem Ltd | Construction | 2018 |
| Advanced Cleaning Solutions Group Limited | Administrative & support | 2025 |
| Advanced Home Technologies Limited | Other services | 2007 |
| Advanced Spraying Solutions Limited | Other services | 2022 |
| Advanced Tiling Limited | Construction | 2015 |
| Advante Limited | Administrative & support | 1960 |
| ADW Air Conditioning Limited | Construction | 2006 |
| ADY Transport Limited | Transport & logistics | 2013 |
| Ae&N Properties Limited | Real estate | 2025 |
| Aeda Services Ltd | Administrative & support | 2025 |
| Aegis Bricks Ltd | Real estate | 2026 |
| Aegis Stone Limited | Real estate | 2024 |
| Aequalis Accounting Ltd | Professional & scientific | 2019 |
| Aequalis Payroll Ltd | Administrative & support | 2022 |
| Aero Greyhounds Limited | Professional & scientific | 2022 |
| Aesthetic by Stevieleah Ltd | Other services | 2024 |
| Aesthetics of Essex Limited | Other services | 2011 |
| Aesthetics of Essex Maldon Limited | Other services | 2020 |
| Aesthetics of Essex of Rayleigh Limited | Other services | 2018 |
| AET Homes LLP | | 2008 |
| AF1 Essentials Limited | Wholesale & retail | 2024 |
| Afas Interiors Ltd | Construction | 2018 |
| Affleck Properties Limited | Real estate | 2023 |
| Affordable Printing Co . Limited | Other services | 2005 |
| Afix Pro Build Ltd | Construction | 2025 |
| Afriai Labs Ltd | Information & communication | 2025 |
| African Wear Ltd | Manufacturing | 2019 |
| Afro Industry Concert Ltd | Professional & scientific | 2025 |
| Afro Jerk Cafe Ltd | Hospitality | 2016 |
| Afro Kitchen Innovations Ltd | Wholesale & retail | 2026 |
| Afrodesi Limited | Wholesale & retail | 2023 |
| AFW Alpha Property Ltd | Real estate | 2024 |
| AG Blackwell Limited | Construction | 2012 |
| AG Business Services Ltd | Professional & scientific | 2023 |
| AG Class Construction Limited | Manufacturing | 2026 |
| AG Contracts Ltd | Construction | 2024 |
| AG Hotels Limited | Real estate | 2020 |
| AG International Hospitality Ltd | Professional & scientific | 2021 |
| AG Property Services (U.K) Limited | Construction | 2026 |
| AGA Services 2026 Ltd | Transport & logistics | 2026 |
| Against the Ropes Promotions Ltd | Arts & recreation | 2021 |
| Agape Care and Cleaning Services Limited | Health & social care | 2021 |
| AGB Heating Ltd | Construction | 2024 |
| AGB Plumbing & Heating Limited | Construction | 2011 |
| Agdv Trans Ltd | Transport & logistics | 2021 |
| Ageing Gracefully Ltd | Administrative & support | 2023 |
| Ageproductionsuk Ltd | Professional & scientific | 2021 |
| Aghastya Ltd | Professional & scientific | 2025 |
| AGL Easy Clean Limited | Administrative & support | 2019 |
| Agnes the Cleaner Ltd | Administrative & support | 2025 |
| Agora C&D Ltd | Construction | 2023 |
| Agrana Group Ltd | Administrative & support | 2025 |
| Agreedit Ltd | Information & communication | 2026 |
| AGS Logistics Solutions Ltd | Transport & logistics | 2024 |
| AGS Transport Solutions Ltd | Transport & logistics | 2022 |
| AH Medical Support Limited | Health & social care | 2020 |
| Ahkda Holdings Limited | Wholesale & retail | 2019 |
| Ahmed and Family Limited | Education | 2024 |
| Ahrise Limited | Information & communication | 2023 |
| AI Integration Systems Ltd | Information & communication | 2025 |
| AI Just Rate Ltd | Information & communication | 2017 |
| AI Research & Development Ltd | Information & communication | 2024 |
| AI Zeum Limited | Wholesale & retail | 2024 |
| Ai-Adoption Ltd | Administrative & support | 2025 |
| Aibinu Ltd | Wholesale & retail | 2025 |
| Aiden's Home Ltd | Real estate | 2023 |
| Aigot Ltd | Construction | 2007 |