| Advoco Legal Services Limited | Professional & scientific | 2017 |
| ADW Financial Limited | Financial services | 2025 |
| Adwals Company Limited | Health & social care | 2013 |
| Adys Takeaway Ltd | Hospitality | 2025 |
| AE & F Ventures Ltd | Wholesale & retail | 2024 |
| AE Europe Limited | Administrative & support | 2003 |
| AE Recruiters Ltd | Other services | 2025 |
| AE Traders Ltd | Other services | 2020 |
| AEC Property Investments Limited | Real estate | 2025 |
| Aegean Hospitality Ltd | Hospitality | 2026 |
| Aegi Holdings Limited | Financial services | 2025 |
| AEL Music Ltd | Professional & scientific | 2026 |
| Aelian Properties Ltd | Real estate | 2023 |
| Aelius Biotech Limited | Professional & scientific | 2018 |
| Aelius Digital Ltd | Information & communication | 2026 |
| Aenclave Ltd | Extraterritorial | 2020 |
| Aeon Blue Solar Ltd | Energy | 2025 |
| Aerial House Ltd | Hospitality | 2026 |
| Aeronavia Limited | Extraterritorial | 1986 |
| Aerospa Finest Ltd | Wholesale & retail | 2018 |
| Aerospa Gatwick North Ltd | Wholesale & retail | 2022 |
| Aerospa Rejuvenate Limited | Wholesale & retail | 2016 |
| Aerospa Revive Limited | Wholesale & retail | 2016 |
| Aerospa Travel Ltd | Wholesale & retail | 2019 |
| Aerospace Metrology & Electromechanical Calibration Limited | Manufacturing | 2004 |
| Aerovision (UK) Ltd | Construction | 2015 |
| Aeroworld Limited | Wholesale & retail | 2024 |
| AES Environmental JV Ltd | Manufacturing | 2023 |
| AES Environmental Ltd | Wholesale & retail | 2020 |
| Aesthetic Angels North East Ltd | Other services | 2025 |
| Aesthetic Cosmetic Procedures Limited | Health & social care | 2018 |
| Aesthetic Medispa Ltd | Other services | 2018 |
| Aesthetics Event Staff Holdings Ltd. | Financial services | 2022 |
| Aesthetics Events Limited | Real estate | 2004 |
| Aestique Ltd | Other services | 2019 |
| Aeterna Property Holdings Ltd | Real estate | 2025 |
| Aeterna Property Ltd | Real estate | 2024 |
| Aeternum Software Ltd | Information & communication | 2009 |
| Aether Business Services Limited | Professional & scientific | 2019 |
| AEY Mechanical Solutions Ltd | Professional & scientific | 2023 |
| AF Visuals Ltd | Manufacturing | 2026 |
| AFA Shopnbuy Ltd | Wholesale & retail | 2025 |
| Afexed Ltd | Information & communication | 2013 |
| Affiliate Angel Limited | Information & communication | 2024 |
| Affordables DTC CIC | Wholesale & retail | 2025 |
| AFG Grill Ltd | Hospitality | 2023 |
| AFG Halal Food Store Limited | Wholesale & retail | 2023 |
| Afghan Grill Restaurant Ltd | Hospitality | 2021 |
| AFH (NE) Ltd | Professional & scientific | 2021 |
| Afnd Services Limited | Professional & scientific | 2024 |
| African Empire Entertainment Ltd | Information & communication | 2025 |
| Afro Food Distribution Ltd | Wholesale & retail | 2024 |
| Afro Security Service Ltd | Administrative & support | 2022 |
| Afroline Trade Ltd | Wholesale & retail | 2019 |
| Afromart Limited | Wholesale & retail | 2026 |
| Afrosphere Films Ltd | Information & communication | 2023 |
| AFT Wealth Management Ltd | Financial services | 2022 |
| After 90 Ltd | Professional & scientific | 2026 |
| Afterwords Limited | Professional & scientific | 2024 |
| AG AMZ Ltd | Wholesale & retail | 2021 |
| AG Coffee Shop Ltd | Hospitality | 2024 |
| AG Digital Consultancy Ltd | Information & communication | 2026 |
| AG Digital Studio Ltd | Professional & scientific | 2024 |
| AG Music Ltd | Arts & recreation | 2024 |
| AG Problem Solution Ltd | Professional & scientific | 2020 |
| AG Property Developing Ltd | Real estate | 2016 |
| AG Shots Limited | Hospitality | 2026 |
| AG UK Art Limited | Manufacturing | 2023 |
| AG12 Community Interest Company | Hospitality | 2026 |
| Agac Property Developments (APD) Ltd | Real estate | 2023 |
| Agata Consulting Ltd | Administrative & support | 2018 |
| Agata's Limited | Administrative & support | 2025 |
| Agelectrotech Ltd | Construction | 2024 |
| Agency Point UK Limited | Administrative & support | 2025 |
| Agentica Limited | Extraterritorial | 2024 |
| Aggro Design Limited | Professional & scientific | 2003 |
| AGH Diagnostics Limited | Health & social care | 2011 |
| Agile Accounting Consultants Ltd | Professional & scientific | 2022 |
| Agile Approach Solutions Ltd | Information & communication | 2023 |
| Agilitas Bidco Limited | Other services | 2020 |
| Agilitas IT Holdings Limited | Administrative & support | 2014 |
| Agilitas Midco Limited | Other services | 2020 |
| Agilitas Topco Limited | Other services | 2020 |
| Agilitas Trustee Limited | Professional & scientific | 2021 |
| Agility Software Limited | Information & communication | 2001 |
| AGJ Group Ltd | Wholesale & retail | 2024 |
| AGL Skills Ltd | Education | 2026 |
| AGR Optimal Training Ltd | Education | 2015 |
| Agricultural Intelligence Systems Development Ltd | Professional & scientific | 2024 |
| Agrimakis Estate Ltd | Wholesale & retail | 2025 |
| Agritech Contracting Ltd | Agriculture & fishing | 2021 |
| AGS Property North East Ltd | Real estate | 2024 |
| AH Renewables Ltd | Administrative & support | 2019 |
| AH Urban Sourcing Ltd | Real estate | 2026 |
| AH Urban Stays Ltd | Hospitality | 2026 |
| AHA Technologies Ltd | Information & communication | 2024 |
| Ahad's Indian Kitchen Ltd | Hospitality | 2020 |
| Ahar (Whitley) Ltd | Hospitality | 2018 |
| Ahbeatsprod Ltd | Information & communication | 2025 |
| AHC Petvet Ltd | Professional & scientific | 2025 |