| Alexander Lennan Ltd | Education | 2022 |
| Alexander Mackenzie Developments Limited | Construction | 2017 |
| Alexandr B Solutions Ltd | Manufacturing | 2016 |
| Alexandra Barnes Consulting Ltd | Professional & scientific | 2021 |
| Alexandra Buck Limited | Professional & scientific | 2014 |
| Alexandra Coman Ltd | Health & social care | 2018 |
| Alexandra Court (Hamble) Management Limited | Hospitality | 2000 |
| Alexandra's Africa Ltd | Arts & recreation | 2012 |
| Alexdigital Limited | Information & communication | 2003 |
| Alexvladlavinia Ltd | Transport & logistics | 2019 |
| Aleynam Limited | Transport & logistics | 2021 |
| Alfa Beta Consulting Ltd | Professional & scientific | 2025 |
| Alfa Oral Care Services Ltd | Health & social care | 2021 |
| Alfa Victor Consultancy Ltd | Information & communication | 2015 |
| Alfatron Services Ltd | Extraterritorial | 2024 |
| Alford Plumbing & Heating Ltd | Construction | 2007 |
| Alfred Close Management Company Limited | Households | 1993 |
| Alfred Integrated Communications Ltd | Professional & scientific | 2024 |
| Alfred London Ltd | Professional & scientific | 2013 |
| Alfreds Fields Management Company Limited | Households | 1997 |
| Alfriston Stores Ltd | Wholesale & retail | 2024 |
| Alga Ltd | Professional & scientific | 2017 |
| Alhaurin Properties Limited | Real estate | 2021 |
| ALI & CIP Total Care Ltd | Health & social care | 2020 |
| ALI Miranda Therapy Limited | Health & social care | 2024 |
| ALI Taxi Hire Ltd | Transport & logistics | 2010 |
| Alianza Global Logistics Services Ltd | Transport & logistics | 2023 |
| Alibi Days Ltd | Arts & recreation | 2023 |
| Alice AI Limited | Information & communication | 2025 |
| Alice Court (Millbrook) Management Limited | Households | 2018 |
| Alice Your Nutritionist Ltd | Health & social care | 2025 |
| Alicia's Cars Ltd | Transport & logistics | 2021 |
| ALIEN8 Ltd | Other services | 2020 |
| Alight Aspects Ltd | Construction | 2010 |
| Align Enterprises Ltd | Construction | 2021 |
| Align Osteopathy Ltd | Health & social care | 2023 |
| Aligner Intelligence Limited | Professional & scientific | 2022 |
| Alikhel Sweets Ltd | Hospitality | 2023 |
| Alimum Ltd | Wholesale & retail | 2022 |
| Alin & Renata Transport Limited | Transport & logistics | 2023 |
| Alina Nastase Ltd | Health & social care | 2016 |
| Alinadunworth Limited | Professional & scientific | 2025 |
| Aline Haddad Ltd | Health & social care | 2010 |
| Aliport Structures Limited | Construction | 2009 |
| Aliquot Properties Limited | Real estate | 2021 |
| Alive Health Care Limited | Health & social care | 2014 |
| Alive Health Care Supported Accommodation C.I.C. | Hospitality | 2023 |
| Alive Health Care Supported Living Ltd | Health & social care | 2023 |
| Alive Tribe Ltd | Education | 2026 |
| ALK Scaffolding Solutions Ltd | Construction | 2026 |
| Alkrar UK Ltd | Wholesale & retail | 2026 |
| ALL About Decorating Ltd | Construction | 2023 |
| ALL About Painting and Decorating Ltd | Construction | 2018 |
| ALL About the Buildings Limited | Administrative & support | 2019 |
| ALL Angles Enterprises Ltd | Wholesale & retail | 2010 |
| ALL Around Group Limited | Transport & logistics | 2025 |
| ALL Aspect Coatings Limited | Construction | 2024 |
| ALL Aspects Improvements Ltd | Construction | 2026 |
| ALL Bases Covered Recruitment Ltd | Administrative & support | 2024 |
| ALL Building & Refurbishment Solutions Ltd | Extraterritorial | 2019 |
| ALL Cars Limited | Wholesale & retail | 2008 |
| ALL Ceylon Foods and Beverages Ltd | Hospitality | 2024 |
| ALL Charged Vehicles Ltd | Wholesale & retail | 2022 |
| ALL Chase Services Ltd | Water & waste | 2022 |
| ALL Clothing & Protection Limited | Wholesale & retail | 2003 |
| ALL Construction Services Ltd | Construction | 2025 |
| ALL Decked UP Ltd | Construction | 2015 |
| ALL Dolled UP Cosmetics Limited | Wholesale & retail | 2021 |
| ALL Floors South Ltd | Construction | 2023 |
| ALL Grow Ltd | Wholesale & retail | 2020 |
| ALL Hours Drain & Plumbing Services Limited | Construction | 1997 |
| ALL in Pack Ltd | Wholesale & retail | 2022 |
| ALL Marine Coatings Ltd | Construction | 2022 |
| ALL Nature Ltd | Wholesale & retail | 2023 |
| ALL Parties and Events Limited | Arts & recreation | 2012 |
| ALL Phases Limited | Extraterritorial | 2021 |
| ALL Ports Customs Clearance Ltd | Transport & logistics | 2017 |
| ALL Talk Prospecting Services Limited | Administrative & support | 2012 |
| ALL the B'S Pet Services Ltd | Other services | 2019 |
| ALL the Little Needs Ltd | Wholesale & retail | 2022 |
| ALL Type Security Limited | Administrative & support | 2026 |
| Allair Services Ltd | Construction | 2022 |
| Allbrook Group Limited | Financial services | 2016 |
| Allbrook Meadow Management Limited | Households | 2015 |
| Allegra-Lux Limited | Real estate | 2003 |
| Allen and Brown PUB Co Ltd | Hospitality | 2024 |
| Allen Home Management Ltd | Households | 2017 |
| Allen Home Solutions Limited | Administrative & support | 2025 |
| Allen Property Management Limited | Real estate | 2002 |
| Allencrest Limited | Professional & scientific | 1991 |
| Allens Barbershop Ltd | Other services | 2023 |
| Allergy Care Limited | Health & social care | 2003 |
| Allevia Ltd | Professional & scientific | 2025 |
| Allfiled UK Limited | Information & communication | 2008 |
| Allfiled.Com Limited | Extraterritorial | 2006 |
| Alliance Consultants (UK) Limited | Real estate | 2011 |
| Alliance Logistics Ltd | Transport & logistics | 2025 |
| Alliance Marine UK Holdings Limited | Financial services | 2018 |
| Alliance Photography Studios Ltd | Professional & scientific | 2021 |
| Alliance Support Services Limited | Administrative & support | 2019 |