| Aldar Development (LSQ) Limited | Financial services | 2023 |
| Aldena Associates Ltd | Administrative & support | 2005 |
| Alderheim Homes Ltd | Households | 2020 |
| Ale&Rob Ltd | Transport & logistics | 2025 |
| Aleherb Care Limited | Public administration | 2021 |
| Alerion Technologies Limited | Construction | 2025 |
| Alex Asos Ltd | Transport & logistics | 2012 |
| Alex UK Limited | Professional & scientific | 2000 |
| Alexander Craig Consulting Limited | Real estate | 2017 |
| Alexander House (Uxbridge) Limited | Real estate | 2025 |
| Alexander James Contracts Limited | Construction | 2012 |
| Alexander James Facades Limited | Construction | 2022 |
| Alexander James Group Limited | Financial services | 2023 |
| Alexander James Utilities Limited | Construction | 2024 |
| Alexander Johnson Limited | Construction | 2011 |
| Alexandra Court (Queen's Walk) Management Company Limited | Households | 1996 |
| Alexed Ltd | Other services | 2024 |
| Alexei Chetrusca Ltd | Construction | 2016 |
| Alfa International Holdings Limited | Real estate | 2014 |
| Alfa Quality Construction Ltd | Construction | 2024 |
| ALG Haulage Ltd | Transport & logistics | 2026 |
| Algarve Golf Courses Limited | Extraterritorial | 1995 |
| Alhasma Dent Limited | Health & social care | 2021 |
| Alhasma H Residential Limited | Real estate | 2024 |
| Alida ALI Beauty Clinic Limited | Wholesale & retail | 2026 |
| Alida ALI Designs Ltd | Wholesale & retail | 2022 |
| Align Shops Fitters Limited | Construction | 2017 |
| Aligner Global Limited | Wholesale & retail | 2021 |
| Alin Rendering Ltd | Construction | 2025 |
| Alina Security Services Ltd | Other services | 2025 |
| Alive Experiences Ltd | Administrative & support | 2025 |
| Alkaline Studio Services Limited | Arts & recreation | 2018 |
| ALL About Nata Limited | Hospitality | 2020 |
| ALL Build London Ltd | Construction | 2018 |
| ALL Events Security Consultants Ltd | Administrative & support | 2017 |
| ALL in Good Spirit Ltd | Hospitality | 2010 |
| ALL Metal Parts Limited | Manufacturing | 2009 |
| ALL Round Access Services Ltd | Construction | 2022 |
| ALL School Recruitment Ltd | Administrative & support | 2025 |
| ALL Seasons Flowers Investments Limited | Financial services | 2025 |
| ALL Square Events Ltd | Arts & recreation | 2025 |
| ALL Things Autism Ltd | Education | 2018 |
| ALL Things Nice Vending Limited | Wholesale & retail | 2007 |
| ALL Works 4 U Ltd. | Construction | 2018 |
| All-Time Radio Cars Limited | Transport & logistics | 1996 |
| Allenby Accountants Ltd | Professional & scientific | 2010 |
| Allenby Property Investments Limited | Real estate | 2025 |
| Allforoneeats Ltd | Hospitality | 2025 |
| Allied Worldwide Services Limited | Information & communication | 2006 |
| Allington Homes Limited | Real estate | 2016 |
| Allround Interiors Ltd | Construction | 2013 |
| Allstar Fireworks Limited | Arts & recreation | 1999 |
| Almac Services Ltd | Transport & logistics | 2015 |
| Almirall Limited | Wholesale & retail | 2007 |
| Almserg Properties Limited | Real estate | 2017 |
| Almys Supermarket Ltd | Wholesale & retail | 2020 |
| Alogic UK PVT Limited | Wholesale & retail | 2018 |
| Alokic Homes Ltd | Real estate | 2026 |
| Alperton Developments Ltd | Real estate | 2024 |
| Alpha Airport Cars Ltd | Transport & logistics | 2007 |
| Alpha Building Restoration Ltd | Other services | 2010 |
| Alpha Home Investments Limited | Real estate | 2024 |
| Alpha Marquees Ltd | Administrative & support | 2025 |
| Alpha Prime Consultancy Ltd | Administrative & support | 2026 |
| Alpha Solar Ltd | Construction | 2021 |
| Alpha Sustainable Holdings Ltd | Financial services | 2024 |
| Alpha Taekwondo Ltd | Arts & recreation | 2021 |
| Alphard Parts Ltd | Wholesale & retail | 2025 |
| ALS Transport Limited | Transport & logistics | 2026 |
| Altaweel Property Ltd | Real estate | 2026 |
| Altered Images (Contractors) Limited | Construction | 1999 |
| Altodigital Networks Limited | Professional & scientific | 2017 |
| Alturos Consulting Ltd | Professional & scientific | 2025 |
| Aluglass Solutions Ltd | Manufacturing | 2023 |
| Alukin Ltd | Wholesale & retail | 2026 |
| Alvaria Technologies UK Limited | Information & communication | 1987 |
| Alvaston Management Company Limited | Households | 2011 |
| Alvi Capital Ltd | Wholesale & retail | 2024 |
| Alwahwood Limited | Extraterritorial | 2022 |
| ALX Property Investments Limited | Real estate | 2021 |
| Alyson Court Management Company Limited | Real estate | 1988 |
| Alyssa Francis Interior Design Ltd | Professional & scientific | 2025 |
| Alzcat Ltd | Real estate | 2021 |
| AM Consult Services Ltd | Professional & scientific | 2025 |
| AM Private Markets Consultancy Ltd | Financial services | 2025 |
| AM Property Marlow Ltd | Real estate | 2026 |
| AM Recruiters Limited | Administrative & support | 2025 |
| Amaarix Group Ltd | Real estate | 2025 |
| Amal Clinic Limited | Health & social care | 2025 |
| Amalfi Bidco Limited | Financial services | 2022 |
| Amalfi Cleanco Limited | Financial services | 2022 |
| Amalfi Midco Limited | Financial services | 2022 |
| Amalgamated Names Limited | Real estate | 2004 |
| Amalin Ltd | Health & social care | 2023 |
| Amanah Estore Ltd | Wholesale & retail | 2025 |
| Amand Food & Wine Ltd | Wholesale & retail | 2026 |
| Amani Foods Ltd | Wholesale & retail | 2008 |
| Amara Sharif Ltd | Wholesale & retail | 2024 |
| Amari Design & Renovations Ltd | Construction | 2026 |
| Amarjitdee Ltd | Households | 2025 |