| Alfred Horizon Ltd | Real estate | 2025 |
| Alganesh Ltd | Real estate | 2024 |
| Algeco Storage Holdings Limited | Professional & scientific | 2006 |
| Algeco Storage Limited | Administrative & support | 1993 |
| Algeco UK Holdings Limited | Administrative & support | 2007 |
| Algeco UK Limited | Manufacturing | 1917 |
| Alhaadiyah Educational Centre Ltd | Education | 2025 |
| ALI Locum Ltd | Professional & scientific | 2020 |
| Ali's Barber (TS18) Limited | Other services | 2021 |
| Alice ROW Ltd | Real estate | 2016 |
| Alipocketmarket Ltd | Wholesale & retail | 2026 |
| ALJ Properties (NE) Ltd | Real estate | 2020 |
| Aljo Consultancy Ltd | Professional & scientific | 2022 |
| ALL About the Hair Ltd | Other services | 2010 |
| ALL Cooked Ltd | Hospitality | 2024 |
| ALL Counties Finance Limited | Extraterritorial | 1980 |
| ALL Food Products Ltd | Wholesale & retail | 2020 |
| ALL Seasons Bespoke Gardens and Driveways Ltd | Administrative & support | 2026 |
| ALL Seasons Windows (N/E) Limited | Manufacturing | 2008 |
| ALL Starz Cheer Collective Ltd | Professional & scientific | 2024 |
| ALL YOU CAN Vape Limited | Manufacturing | 2018 |
| Allan Family Properties Ltd | Real estate | 2025 |
| Allbrite Healthcare Ltd | Health & social care | 2016 |
| Allens West Property Limited | Real estate | 2025 |
| Alliance Holdings Ltd | Real estate | 2022 |
| Alliance Psychological Services Ltd | Health & social care | 2006 |
| Alliance Teesside Ltd | Financial services | 2013 |
| ALLIN1.APP Ltd. | Professional & scientific | 2023 |
| Allison Consultants Ltd | Construction | 2025 |
| Allison Property Investments Ltd | Real estate | 2023 |
| Allo Mobile Limited | Transport & logistics | 2016 |
| Allure Healthcare Ltd | Health & social care | 2022 |
| Allure Salon (NE) Ltd | Other services | 2022 |
| Almark Limited | Manufacturing | 2001 |
| Almas (NE) Ltd | Hospitality | 2023 |
| Alpha Developments (Bradford) Ltd | Construction | 2015 |
| Alpha Developments (BRADFORD2) Ltd | Real estate | 2016 |
| Alpha Developments (Huddersfield) Ltd | Real estate | 2014 |
| Alpha Developments (Loughborough) Ltd | Real estate | 2014 |
| Alpha Developments (Preston) Ltd | Real estate | 2015 |
| Alpha Developments (Stoke) Ltd | Administrative & support | 2016 |
| Alpha Developments (STOKE1) Ltd | Real estate | 2015 |
| Alpha Developments (STOKE2) Ltd | Administrative & support | 2016 |
| Alpha Holdings (GB) Ltd | Real estate | 2013 |
| Alpha Properties (Bradford) Ltd | Administrative & support | 2016 |
| Alpha Properties (Leicester) Limited | Professional & scientific | 2014 |
| Alpha Psychology Ltd | Education | 2021 |
| Alpha Sheds Ltd | Construction | 2025 |
| Alpha SIX Fire Door Consultancy Limited | Public administration | 2024 |
| Alpha Student Management Ltd | Administrative & support | 2017 |
| ALR Media Services Ltd | Professional & scientific | 2026 |
| Alrahi & Singh Limited | Wholesale & retail | 2010 |
| Alrahi Holdings Limited | Financial services | 2026 |
| Alternative Farming Industries Ltd | Agriculture & fishing | 2021 |
| Altitude Video and Photography Ltd | Information & communication | 2014 |
| ALU Healthcare and Data Ltd | Health & social care | 2023 |
| Alubaba Ltd | Wholesale & retail | 2022 |
| Always Advancing Fencing Specialists Ltd | Manufacturing | 2024 |
| Alynn Rail Consultancy Ltd | Construction | 2024 |
| AM & Sons Holdings Limited | Financial services | 2025 |
| AM Consulting Solutions Ltd | Professional & scientific | 2025 |
| AM Events & Promotions Ltd | Health & social care | 2025 |
| AM Food Service Ltd | Wholesale & retail | 2026 |
| Aman Estates & Property Ltd | Real estate | 2008 |
| Amana Construction Ltd | Construction | 2026 |
| Amana Property Solutions Ltd | Real estate | 2026 |
| Amazing Grace Concepts Ltd | Health & social care | 2025 |
| Amazing Interactives Limited | Information & communication | 2004 |
| Amber Louise Chiropractic Limited | Health & social care | 2026 |
| Ambient Air Conditioning UK Limited | Construction | 2004 |
| Ambrose Wilson Kitchens Limited | Construction | 2026 |
| American Wholesale Suppliers (N.E) Ltd | Wholesale & retail | 2020 |
| Amery Properties Ltd | Real estate | 2024 |
| Amethyst & Aura Ltd | Wholesale & retail | 2021 |
| AMF Homes Ltd | Real estate | 2025 |
| AMG Contracting Services Ltd | Other services | 2023 |
| Amgaufo Ltd | Health & social care | 2021 |
| AMH Business Consultants Limited | Real estate | 2020 |
| Amiedoors Ltd | Construction | 2026 |
| Amisha Nomira Limited | Hospitality | 2025 |
| AMK E&I Limited | Construction | 2014 |
| Ammm Access Ltd | Construction | 2024 |
| Amore Pezzeria Ltd | Hospitality | 2025 |
| Amoreb Ltd | Other services | 2026 |
| Amphora Intermediate I Limited | Other services | 2018 |
| Amplify Properties Ltd | Real estate | 2022 |
| Ampoxe Ltd | Professional & scientific | 2024 |
| Amprex Limited | Wholesale & retail | 2025 |
| Amrcil Limited | Wholesale & retail | 2026 |
| AMS Cleaning Services Ltd | Administrative & support | 2021 |
| AMW Design Ltd | Professional & scientific | 2019 |
| AN Cleaning Limited | Administrative & support | 2025 |
| Anasuya Global Ltd | Wholesale & retail | 2026 |
| Anathoth Bliss Echocardiography Limited | Health & social care | 2024 |
| Anchoreach C.I.C. | Health & social care | 2020 |
| AND NOW for ME Ltd | Other services | 2019 |
| Anderson Barrowcliff (1913) LLP | | 2008 |
| Anderson Barrowcliff Holdings LLP | | 2024 |
| Anderson Barrowcliff Limited | Professional & scientific | 2024 |
| Anderson Wratten Ltd | Administrative & support | 2012 |