| Alfa Topco Limited | Information & communication | 2014 |
| Alfanuvo Ltd | Information & communication | 2018 |
| Alfie's Designs Ltd | Wholesale & retail | 2020 |
| Algemax Limited | Other services | 2018 |
| Algosh Limited | Hospitality | 2024 |
| Algrano Limited | Professional & scientific | 2016 |
| ALI Ahmad Limited | Information & communication | 2012 |
| ALI Alhamdani Limited | Administrative & support | 2014 |
| ALI UK Properties Ltd | Real estate | 2024 |
| Aliaron Limited | Administrative & support | 2014 |
| Alice's Store Ltd | Wholesale & retail | 2020 |
| Alien Heart Creations Ltd. | Administrative & support | 2024 |
| Align Marketing Consultancy Limited | Professional & scientific | 2025 |
| Aliquis (UK) Limited | Construction | 2009 |
| Alis Capital Ltd | Real estate | 2024 |
| Alis Medlegal Ltd | Health & social care | 2019 |
| Alison Lloyd ISO Services Ltd | Information & communication | 2023 |
| Alison Singleton & Associates Ltd | Administrative & support | 2005 |
| Alison's Cafe Limited | Hospitality | 2025 |
| Alive Imagery Limited | Professional & scientific | 2017 |
| Alive Photography Ltd | Professional & scientific | 2025 |
| Alive Visualisation Ltd | Professional & scientific | 2025 |
| Alix Diemont Psychology Ltd | Health & social care | 2025 |
| Aliya Jaffer Ltd | Education | 2019 |
| Aljaselle Company Limited | Real estate | 2025 |
| ALL About Sharepoint Ltd | Information & communication | 2012 |
| ALL About the Lake Limited | Other services | 2021 |
| ALL About the Trees Limited | Financial services | 2022 |
| ALL Boys Music Limited | Information & communication | 1984 |
| ALL Construcion Ltd | Construction | 2026 |
| ALL Dunne and Dusted Ltd | Administrative & support | 2018 |
| ALL MIX Cheshire Limited | Manufacturing | 2017 |
| ALL MIX Concrete Ltd | Manufacturing | 2018 |
| ALL Things Business Ltd | Professional & scientific | 2023 |
| ALL Things Decor Ltd | Wholesale & retail | 2019 |
| ALL Things Food and Drink Ltd | Hospitality | 2020 |
| ALL Things Motorbikes Ltd | Wholesale & retail | 2026 |
| ALL- CAD Limited | Administrative & support | 2007 |
| ALL- Star Handyman Ltd | Construction | 2025 |
| Allan Barnett Installations Ltd. | Construction | 2013 |
| Allan W Wood Limited | Administrative & support | 2010 |
| Allayna Investments Limited | Real estate | 2023 |
| Allease Investments Ltd | Real estate | 2025 |
| Allegiance Limited | Administrative & support | 2008 |
| Allegiant Finance Services Ltd | Information & communication | 2010 |
| Allen & Associates Ltd | Administrative & support | 2025 |
| Allenby Consultancy Limited | Information & communication | 2009 |
| Allens' Tax Disputes Limited | Professional & scientific | 2022 |
| Alleyo C.I.C. | Information & communication | 2015 |
| Allez Allez Sport Travel Ltd | Administrative & support | 2023 |
| Alliance Connectivity Group Ltd | Financial services | 2024 |
| Alliance Connectivity Ltd | Other services | 2020 |
| Alliance Freight (UK) Ltd | Transport & logistics | 2023 |
| Allie Cresswell Limited | Other services | 2018 |
| Allie Engineering Limited | Professional & scientific | 2017 |
| Allied Access Limited | Construction | 2018 |
| Allied Cables Limited | Wholesale & retail | 1987 |
| Allied Conductors Limited | Wholesale & retail | 2012 |
| Allied Export Ltd | Extraterritorial | 2011 |
| Allied Motion Limited | Health & social care | 2025 |
| Allied Roofing (Holdings) Ltd | Other services | 2012 |
| Allied Roofing and Construction Limited | Construction | 1990 |
| Allison Fluid Power Limited | Extraterritorial | 1998 |
| Allmac (NW) Ltd | Manufacturing | 2019 |
| Allmec Engineering Limited | Manufacturing | 1998 |
| Allnice Ltd | Other services | 2023 |
| Alloy Scaffolding Hire Ltd | Administrative & support | 2005 |
| Alloyman Limited | Manufacturing | 2015 |
| Allpoint Safety Limited | Wholesale & retail | 1996 |
| Allred Electrical Factors Limited | Wholesale & retail | 1999 |
| Allround DB Solutions Limited | Information & communication | 2012 |
| Allstar Aviation Ltd | Manufacturing | 2023 |
| Allswell Consulting Ltd | Administrative & support | 2022 |
| Allure DDC Ltd | Wholesale & retail | 2018 |
| Allure Home Textiles Ltd | Wholesale & retail | 2023 |
| Allwork Construction Limited | Administrative & support | 2024 |
| Allyship CIC | Education | 2026 |
| ALM Civil Engineering Limited | Administrative & support | 2014 |
| ALM Professional Services Ltd | Wholesale & retail | 2021 |
| Almeera H Ltd | Administrative & support | 2025 |
| Alnahyan Limited | Other services | 2022 |
| Alnwick Site Services Limited | Construction | 2023 |
| Alpa Group Limited | Administrative & support | 2020 |
| Alpadrino Limited | Hospitality | 2025 |
| Alpha Biolaboratories Analytical Ltd | Professional & scientific | 2015 |
| Alpha Biolaboratories Corporate Limited | Professional & scientific | 2015 |
| Alpha Biolaboratories COVID-19 Testing Limited | Professional & scientific | 2020 |
| Alpha Biolaboratories Holdings Limited | Financial services | 2023 |
| Alpha Biolaboratories Legal Limited | Professional & scientific | 2012 |
| Alpha Biolaboratories Limited | Professional & scientific | 2016 |
| Alpha Biolaboratories Retail Limited | Professional & scientific | 2012 |
| Alpha Care & Recruitment Ltd | Administrative & support | 2018 |
| Alpha Engineering Design Limited | Administrative & support | 2015 |
| Alpha Markhor Limited | Administrative & support | 2026 |
| Alpha Omega Project Management Limited | Professional & scientific | 2005 |
| Alpha RAW Feeds Ltd. | Administrative & support | 2020 |
| Alpha Realm Ltd | Health & social care | 2025 |
| ALPHA2 Project Services Ltd | Professional & scientific | 2020 |
| ALPHA24 Care Ltd | Administrative & support | 2016 |
| Alphacare NW DSS Ltd | Health & social care | 2024 |