| Aero Ciprian Ltd | Manufacturing | 2025 |
| Aero Hoinar Ltd | Manufacturing | 2024 |
| Aero Maveric Solutions Ltd | Manufacturing | 2024 |
| Aero Mezul Ltd | Manufacturing | 2024 |
| Aero Serv Engineering Ltd | Wholesale & retail | 2026 |
| Aero.Mme Ltd | Manufacturing | 2026 |
| Aerobrand Ltd | Professional & scientific | 2016 |
| Aerocabin Engineering Ltd | Manufacturing | 2025 |
| Aerodrome Croydon Limited | Real estate | 2022 |
| Aerodrome Entertainment Limited | Other services | 2022 |
| Aerodrome Ltd | Arts & recreation | 2019 |
| Aerodrome Properties Limited | Administrative & support | 2022 |
| Aerogriff Ltd | Manufacturing | 2018 |
| Aerokast Ltd | Manufacturing | 2025 |
| Aerolearn Ltd | Education | 2026 |
| Aeroman Ltd | Manufacturing | 2024 |
| Aeromech Ltd | Manufacturing | 2021 |
| Aeronicnat Ltd | Manufacturing | 2017 |
| AEROSMW777 Ltd | Manufacturing | 2024 |
| Aerotech MIG Ltd | Manufacturing | 2025 |
| Aerotocha Ltd | Manufacturing | 2024 |
| Aeternitas International Ltd | Financial services | 2025 |
| Aetha Consulting Limited | Professional & scientific | 2011 |
| Aetheria-X Ltd | Professional & scientific | 2023 |
| Aeuil Carpentry Limited | Construction | 2022 |
| AF Travel Limited | Administrative & support | 2021 |
| Af's Collection Limited | Wholesale & retail | 2013 |
| AFF International (UK) Limited | Wholesale & retail | 1996 |
| Affargo Ltd | Wholesale & retail | 2021 |
| AFFIX11 Ltd | Real estate | 2023 |
| Affr Ltd | Construction | 2025 |
| Aflex 786 Enterprises Ltd | Wholesale & retail | 2026 |
| African Biogenome Project Limited | Professional & scientific | 2026 |
| African Caribbean Research Group CIC | Education | 2025 |
| African Cuisine Network Limited | Information & communication | 2024 |
| African Treasures Ltd | Wholesale & retail | 2014 |
| Africanfire Limited | Extraterritorial | 2007 |
| Africfood Catering Events Limited | Hospitality | 2025 |
| Afrixis Ltd | Information & communication | 2026 |
| Afrizia Markets Ltd | Wholesale & retail | 2025 |
| AFT Consult Limited | Professional & scientific | 2014 |
| After Asana Limited | Other services | 2026 |
| After Dark Cleaners Limited | Administrative & support | 2024 |
| Afternoon Tease Ltd | Hospitality | 2011 |
| AG Inspections Ltd | Manufacturing | 2025 |
| AG Motors Limited | Wholesale & retail | 2009 |
| AG Motors Over Limited | Wholesale & retail | 2017 |
| AG Property Maintenance Solutions Ltd | Construction | 2026 |
| AG Ramrous Holdings Ltd | Financial services | 2024 |
| AG Store Ltd | Transport & logistics | 2020 |
| AGA Composites Ltd | Manufacturing | 2023 |
| AGA Medicals Ltd | Health & social care | 2020 |
| Agah Investment Group Ltd | Administrative & support | 2022 |
| Agata Communications Limited | Professional & scientific | 2020 |
| Agecurve Limited | Professional & scientific | 2015 |
| Agena Ltd | Information & communication | 1997 |
| Agenome Ltd | Professional & scientific | 2023 |
| Agent 108 Ltd | Wholesale & retail | 2014 |
| Agent Oriented Software Limited | Information & communication | 2001 |
| Agentix-Ai Ltd | Information & communication | 2025 |
| Agfa Healthcare UK Limited | Information & communication | 2007 |
| Agfa IJC Limited | Manufacturing | 2015 |
| AGG Pro Ltd | Financial services | 2019 |
| Aggiec Luxury Trading Ltd | Wholesale & retail | 2020 |
| Aggregate Processing and Recycling (Holdings) Limited | Financial services | 2012 |
| Aggregate Processing and Recycling Limited | Manufacturing | 1996 |
| Aggregates Recycling Limited | Extraterritorial | 1969 |
| AGI Labs Ltd | Wholesale & retail | 2024 |
| Agile Analog Ltd. | Administrative & support | 2017 |
| Agile Biomedical Consultants Limited | Professional & scientific | 2019 |
| Agile Estates Ltd | Real estate | 2019 |
| Agile User Experience Ltd | Information & communication | 2012 |
| Agileflow Ltd | Information & communication | 2012 |
| Agileigniter Limited | Information & communication | 2018 |
| AGM Media Ltd | Professional & scientific | 2024 |
| AGN Creative Arts Ltd | Wholesale & retail | 2026 |
| Agnotis Care Products Co., Ltd | Administrative & support | 2020 |
| Agodrive Ltd | Education | 2011 |
| Agora Foundation | Education | 2018 |
| Agora Restaurants Limited | Hospitality | 2004 |
| AGR Inspections Ltd | Manufacturing | 2025 |
| Agraganyaya Fashion Ltd | Wholesale & retail | 2020 |
| Agrethos Ltd | Professional & scientific | 2020 |
| Agricole Limited | Agriculture & fishing | 2002 |
| Agricycle Innovation Ltd | Water & waste | 2023 |
| Agro-Tech Group Holding Ltd | Agriculture & fishing | 2023 |
| Agrocanturk Tarim Kimya DIS Ticaret Ltd | Mining & quarrying | 2026 |
| Agroshield Wholesale Ltd | Wholesale & retail | 2025 |
| Agroupco Ltd | Other services | 2017 |
| AGS Real Capital Freehold Ltd | Real estate | 2025 |
| Agtm Estate Limited | Real estate | 2020 |
| Aguila International Risk Ltd | Financial services | 2014 |
| Aguila Risk Group Limited | Professional & scientific | 2025 |
| Aguila Risk Limited | Professional & scientific | 2023 |
| Aguila Risk Management Limited | Financial services | 2025 |
| Aguila Risk Services Limited | Professional & scientific | 2025 |
| AGW Lettings Ltd | Real estate | 2021 |
| AH Asset Management Limited | Professional & scientific | 2024 |
| AH Electrical (Cambridge) Limited | Construction | 2015 |
| AH Farming Ltd | Agriculture & fishing | 2013 |