| ADG Mindcare Ltd | Public administration | 2021 |
| ADH Design Studio Ltd | Professional & scientific | 2026 |
| Adity Dance CIC | Arts & recreation | 2023 |
| Adnanhayat Ltd | Administrative & support | 2023 |
| ADP Delivery Limited | Transport & logistics | 2023 |
| ADR Solutions (UK) Limited | Professional & scientific | 2013 |
| Adrian & Goran Limited | Professional & scientific | 2007 |
| Adrian Martin Ltd | Construction | 2022 |
| Adriatik HCW Ltd | Administrative & support | 2017 |
| Adstar Properties Limited | Administrative & support | 1970 |
| Advance Solutions ( London ) Ltd | Administrative & support | 2010 |
| Advanced AI Properties Ltd | Real estate | 2024 |
| Advanced Computer Services (London) Limited | Information & communication | 2003 |
| Advanced Hypnotherapy Limited | Health & social care | 2017 |
| Advanced Tutors Limited | Real estate | 2020 |
| Advanced Warning and Communicated Systems UK Ltd | Construction | 2010 |
| Advantage Health Solutions Ltd | Health & social care | 2012 |
| Adventures Day Nursery Ltd | Education | 2013 |
| Advoco Ltd | Professional & scientific | 2008 |
| AF Renovations Ltd | Construction | 2020 |
| Affinity Ehealth Ltd | Information & communication | 2019 |
| Affordable Minibuses Ltd | Transport & logistics | 2021 |
| AFRIKA28 Ltd | Hospitality | 2026 |
| Aftertherainproductions Ltd | Information & communication | 2025 |
| AG Advisory Services Ltd | Professional & scientific | 2021 |
| AG Graphics Ltd | Extraterritorial | 2014 |
| AG Jewellery Limited | Manufacturing | 2025 |
| AG Kaneva Ltd | Administrative & support | 2011 |
| Ag-Iatm Consulting Services Limited | Information & communication | 2018 |
| AGA Digital Ltd | Information & communication | 2017 |
| Agemar UK Limited | Administrative & support | 2019 |
| Agemus Limited | Construction | 2019 |
| AGK Advisory Ltd | Professional & scientific | 2023 |
| AGK Driver Ltd | Transport & logistics | 2025 |
| Agkuk Limited | Education | 2013 |
| Ahaa International Ltd | Wholesale & retail | 2016 |
| Ahads' Properties Ltd | Real estate | 2024 |
| Ahern Asbestos Services Limited | Professional & scientific | 1991 |
| Ahern Hazardous Waste Services Limited | Administrative & support | 1985 |
| Ahern Land Reclamation Limited | Mining & quarrying | 1982 |
| Ahern Skips Limited | Professional & scientific | 2001 |
| Ahern Waste Management Services Limited | Professional & scientific | 2001 |
| AHP Trading Ltd | Administrative & support | 2021 |
| AI Homes Real Estate Ltd | Real estate | 2024 |
| AI Risk Analytics Ltd | Information & communication | 2025 |
| AI Tech Solutions Ltd | Information & communication | 2012 |
| Aidan Prior Communications Limited | Professional & scientific | 2002 |
| Air Conditioning Warehouse Ltd | Real estate | 2020 |
| Aitch D Ltd | Administrative & support | 2024 |
| Aitour Ltd | Administrative & support | 2023 |
| AJ Dental Ltd | Health & social care | 2024 |
| AJ Financial and Immigration Ltd | Professional & scientific | 2023 |
| AJ Mobile & Vape Ltd | Other services | 2018 |
| AJ3 Ltd | Wholesale & retail | 2020 |
| AJ4SN Ltd | Professional & scientific | 2016 |
| AJD Bros Ltd | Wholesale & retail | 2021 |
| AJD Bros Supplements Ltd | Wholesale & retail | 2022 |
| AJH Estates Limited | Real estate | 2020 |
| AJK Cleaning Services Limited | Administrative & support | 2009 |
| Ajwa & Aish Ltd | Wholesale & retail | 2025 |
| AK Prema Consulting Ltd | Professional & scientific | 2019 |
| AK9 Security Ltd | Administrative & support | 2018 |
| AKA Kickboxing Ltd | Arts & recreation | 2026 |
| Akin VEG Ltd | Hospitality | 2020 |
| Akira Property Consultancy Ltd | Professional & scientific | 2024 |
| Aksd Builders Ltd | Construction | 2025 |
| Akshar News Limited | Wholesale & retail | 2013 |
| AKY Brothers Limited | Transport & logistics | 2023 |
| AL Karm Limited | Wholesale & retail | 2024 |
| AL Raziq Enterprises Limited | Administrative & support | 2020 |
| AL Sherman Consult Ltd | Professional & scientific | 2025 |
| Al-Mudassar Trust | Education | 2007 |
| Alacati Grill Ltd | Hospitality | 2020 |
| Alaksma Limited | Education | 2026 |
| Alam and H Ltd | Real estate | 2025 |
| Alam and Kamal Investments Limited | Real estate | 2020 |
| Alam and Q Investments Ltd | Construction | 2017 |
| Alam Ltd | Hospitality | 2005 |
| Alan Traders Limited | Information & communication | 2023 |
| Alanna Investments Ltd | Real estate | 2019 |
| Alba - FR Ltd | Construction | 2010 |
| Albany Court Flats (Woodford) Limited | Households | 1969 |
| Albion Waterside Limited | Financial services | 2024 |
| Albone Associates Ltd | Real estate | 2019 |
| Alcaeus Risk and Compliance Limited | Professional & scientific | 2015 |
| Alcocare Limited | Health & social care | 2025 |
| Alderlea Property Ltd | Administrative & support | 2024 |
| Alderwood House RTM Company Ltd | Households | 2023 |
| Aleema Investments Ltd | Real estate | 2024 |
| Aleksandr Iupashevskii Building Services Limited | Construction | 2025 |
| Alex Charles Limited | Households | 2024 |
| Alex George Ophthalmics Ltd. | Health & social care | 2008 |
| Alex Shortt EYE Surgery Ltd | Health & social care | 2015 |
| Alexander ASH & Co. Limited | Professional & scientific | 2001 |
| Alexander Brook Properties Limited | Real estate | 2020 |
| Alexandra DE Curtis Limited | Other services | 2015 |
| Alfa Construction London Ltd | Construction | 2022 |
| Alfalah Cars Ltd | Transport & logistics | 2022 |
| Alffa Investments Ltd | Professional & scientific | 2020 |
| Alfreds Way Investments (NO. 2) Limited | Construction | 1972 |