| ARS Distributors Limited | Wholesale & retail | 2025 |
| ARS Locum Limited | Other services | 2013 |
| ARS London Investments Ltd | Real estate | 2021 |
| Arslan Bhatti Ltd | Wholesale & retail | 2024 |
| Art Arch Planning and Design Limited | Professional & scientific | 2018 |
| Art Electrics London Limited | Construction | 2024 |
| Art Genpower Solutions Ltd | Wholesale & retail | 2019 |
| Art JAR Ltd | Arts & recreation | 2017 |
| Art of Beauty Limited | Other services | 2023 |
| Art-Bud Bathrooms Ltd | Construction | 2024 |
| Art-P Building Services Ltd | Administrative & support | 2014 |
| Arth Consultancy Ltd | Professional & scientific | 2020 |
| Artichoke Habitat Ltd | Real estate | 2024 |
| Artisan Contract Solutions Ltd | Construction | 2021 |
| Artknight Ltd | Professional & scientific | 2020 |
| Artora Worldwide Limited | Wholesale & retail | 2022 |
| ARV Estates Limited | Households | 2019 |
| Arvin Build Limited | Construction | 2025 |
| Arvindkumar and Co. Ltd | Real estate | 2023 |
| Arvisat Technologies and Solutions Limited | Information & communication | 2014 |
| Arwa Retail Ltd | Wholesale & retail | 2026 |
| Arwin Consultancy Ltd | Information & communication | 2023 |
| Arya Developers Limited | Real estate | 2015 |
| Arya Infinity Ltd | Information & communication | 2026 |
| Aryan Herbals Ltd | Wholesale & retail | 2010 |
| Aryan Kitchen and Bedroom Limited | Manufacturing | 2020 |
| Aryan Ventures Limited | Real estate | 1994 |
| AS Developments (London) Ltd | Construction | 2026 |
| AS JS Malhotra Limited | Real estate | 2024 |
| AS Mobile London Ltd | Wholesale & retail | 2022 |
| AS Sachdev Limited | Wholesale & retail | 2025 |
| AS Skyline Constructions Ltd | Construction | 2026 |
| AS Steel Fabrication Limited | Professional & scientific | 2023 |
| Asanabil Limited | Wholesale & retail | 2018 |
| Asangha Ltd | Financial services | 2023 |
| Ascensa Designs Limited | Professional & scientific | 2025 |
| Ascensis Operations Limited | Professional & scientific | 2026 |
| Ascnd London Ltd | Manufacturing | 2026 |
| Ascog Properties Limited | Real estate | 2021 |
| Asees & Arian Ltd | Wholesale & retail | 2025 |
| Asees Investments Limited | Real estate | 2023 |
| Asees Nijjar Transport Ltd | Transport & logistics | 2026 |
| Asees Trading Ltd | Wholesale & retail | 2021 |
| ASG Enterprises Limited | Administrative & support | 2007 |
| ASH B Properties Ltd | Real estate | 2025 |
| ASH Grove Hounslow Developments Limited | Construction | 2023 |
| ASH Line 3 Ltd | Construction | 2025 |
| Asha Expo & Co Limited | Wholesale & retail | 2007 |
| Asha Nair Ltd | Health & social care | 2024 |
| Asharora Properties Ltd | Real estate | 2019 |
| Ashbright Agency Limited | Health & social care | 2018 |
| Ashiana Wedding Hall Ltd | Hospitality | 2014 |
| Ashley Brooks Coaching Limited | Information & communication | 2011 |
| Ashok Lettings Ltd | Real estate | 2022 |
| Ashpreet Ltd | Real estate | 2010 |
| Ashwani Malik Ltd | Transport & logistics | 2022 |
| ASI Consulting Services Limited | Information & communication | 2023 |
| ASI PVT. Ltd | Information & communication | 2023 |
| Asia Logistics Services (UK) Limited | Transport & logistics | 2006 |
| Asian Meat and Poultry Wholesalers Ltd | Wholesale & retail | 2025 |
| Asian Supermarket Tooting Ltd | Wholesale & retail | 2025 |
| Asianweddingphotographer Ltd | Professional & scientific | 2024 |
| Asiatic Superstore Limited | Wholesale & retail | 2025 |
| Asig (U.K.) Limited | Transport & logistics | 1988 |
| Asim Appliances Ltd | Wholesale & retail | 2025 |
| Asimrise Ltd | Wholesale & retail | 2026 |
| ASK 4 Developers Limited | Construction | 2012 |
| ASK London Properties Limited | Real estate | 2025 |
| ASK4TASK Group Ltd | Wholesale & retail | 2024 |
| Askara Tufail Designs Limited | Professional & scientific | 2026 |
| Askn Group Ltd | Construction | 2026 |
| ASL Alpha Ltd | Administrative & support | 2023 |
| ASL Facilities Management Ltd | Administrative & support | 2022 |
| ASL Services and Management Ltd | Hospitality | 2019 |
| Asli Desi Limited | Manufacturing | 2025 |
| ASM Construction and Investment Ltd | Construction | 2024 |
| ASM Freight Services Ltd | Transport & logistics | 2018 |
| Asmi Fintech Limited | Information & communication | 2016 |
| Asmm Services Limited | Administrative & support | 2017 |
| ASP Risktec Ltd | Extraterritorial | 2014 |
| Aspenfort Ltd | Wholesale & retail | 2024 |
| Asper Marble & Granite Limited | Construction | 1999 |
| Aspera Technologies Limited | Information & communication | 2014 |
| Aspirations Academies Trust | Education | 2011 |
| Aspire Housing Solutions Limited | Hospitality | 2025 |
| Aspire Innovation Ltd | Wholesale & retail | 2025 |
| Aspire Living & Care Limited | Health & social care | 2025 |
| Aspire Living Solutions Ltd | Health & social care | 2025 |
| Aspire Software Solutions Ltd | Information & communication | 2014 |
| Aspire Staffing Solutions Limited | Administrative & support | 2024 |
| ASPIRE2EXCEL.ORG Ltd | Education | 2024 |
| Asraa Investment Limited | Real estate | 2026 |
| Asrex Services Limited | Information & communication | 2025 |
| Asset Finishes Limited | Construction | 2017 |
| Asset Investment Properties Limited | Real estate | 2015 |
| Assethive Limited | Real estate | 2025 |
| Assetvault Limited | Information & communication | 2016 |
| Assi Electrical and Security Ltd | Construction | 2018 |
| Associated Macadams Limited | Construction | 2026 |
| Association of International Courier & Express Services | Other services | 1982 |