| ALB0X Subsea Ltd | Professional & scientific | 2022 |
| Albert Buildings Limited(The) | Real estate | 1885 |
| Albon Writing Solutions Limited | Professional & scientific | 2014 |
| Albusit Limited | Administrative & support | 2014 |
| ALC Cata CI Ltd | Transport & logistics | 2018 |
| Alcester Road (Freehold) Limited | Real estate | 2004 |
| Alcohols (North West) Limited | Professional & scientific | 1995 |
| Alcohols Limited | Manufacturing | 1955 |
| Alec Findlay Creative Ltd | Professional & scientific | 2021 |
| Alex Driver Ltd | Transport & logistics | 2018 |
| Alex DUM Trans Ltd | Transport & logistics | 2020 |
| Alex Leask Associates Limited | Education | 2013 |
| Alex LEE Kitchens 2010 Ltd | Wholesale & retail | 2010 |
| Alex Warwick Limited | Wholesale & retail | 2017 |
| Alex&Alex Ltd | Construction | 2023 |
| Alexander Enabling Ltd | Construction | 2023 |
| Alexander Logistic Ltd | Transport & logistics | 2022 |
| Alexandra's Garden Limited | Extraterritorial | 2022 |
| Alexandru Bouros Transport Ltd | Transport & logistics | 2017 |
| Alexandrub Ltd | Transport & logistics | 2019 |
| Alexia Chandler BDS Limited | Health & social care | 2026 |
| Alicap Ltd | Extraterritorial | 2019 |
| Align Case Management Ltd | Professional & scientific | 2023 |
| Aligned People Technology Ltd | Administrative & support | 2026 |
| Alika Homes Limited | Real estate | 2021 |
| Alindan Ltd | Manufacturing | 2018 |
| Alinmes Ltd | Administrative & support | 2016 |
| Alipropco Ltd | Real estate | 2019 |
| Alison Brimley Consultancy Ltd | Administrative & support | 2011 |
| Alison Lamont Design Limited | Professional & scientific | 2012 |
| Alistar Transport Ltd | Transport & logistics | 2018 |
| Aliza Healthcare Limited | Health & social care | 2025 |
| ALL Around Electrical Limited | Manufacturing | 2012 |
| ALL Metal Fabrication Limited | Manufacturing | 2015 |
| ALL Round Solutions Limited | Arts & recreation | 2020 |
| ALL Vehicle Campers Ltd | Manufacturing | 2025 |
| ALL Wrapped UP (Lutterworth) Limited | Wholesale & retail | 2023 |
| All-Star Cargo Ltd | Transport & logistics | 2014 |
| Allen Groundworks Ltd | Construction | 2024 |
| Allframe Limited | Wholesale & retail | 1986 |
| Allied Domecq First Pension Trust Limited | Professional & scientific | 1978 |
| Allied Domecq Second Pension Trust Limited | Extraterritorial | 1977 |
| Allied Finlaw UK Ltd | Professional & scientific | 2012 |
| Allround Logistics Ltd | Wholesale & retail | 2025 |
| Allsorts Publications Limited | Information & communication | 2011 |
| Allstar Signings 4U Limited | Administrative & support | 2005 |
| Alma Supermarket (Rugby) Limited | Wholesale & retail | 2014 |
| Almanac Commercial Holdings Limited | Real estate | 2026 |
| Almanac Investments Limited | Real estate | 2024 |
| Alpina Auto Works Ltd | Wholesale & retail | 2026 |
| ALT K Dance Limited | Arts & recreation | 2018 |
| Altchain Consulting Ltd | Information & communication | 2017 |
| Alternative Independent Inventory Services Limited | Real estate | 2013 |
| Altira Group Limited | Information & communication | 2026 |
| Altrica Ltd | Professional & scientific | 2022 |
| ALY Fast Trans Ltd | Transport & logistics | 2025 |
| Alyannis Trans Ltd | Transport & logistics | 2018 |
| Alyon Cynthia Care Services Ltd | Health & social care | 2020 |
| AM Investments & Properties Ltd | Real estate | 2025 |
| AM Joinery Ltd | Manufacturing | 2023 |
| Amaltthea Ltd | Transport & logistics | 2023 |
| Amanoh Ltd | Administrative & support | 2019 |
| Amara Grace Photography Ltd | Professional & scientific | 2019 |
| Amaze Distribution Limited | Wholesale & retail | 2024 |
| Amber Utilities Ltd | Construction | 2016 |
| Amber Valley Developments LLP | | 2011 |
| Amber Valley Limited | Manufacturing | 1995 |
| Amber Valley Payroll Services Limited | Administrative & support | 2015 |
| Amberdee Investments Ltd | Financial services | 2026 |
| Amberley Consultancy Ltd | Professional & scientific | 2023 |
| Ambition Developments Ltd | Wholesale & retail | 2019 |
| Amblecoat Hand Car Wash Limited | Other services | 2018 |
| Ambra Limited | Transport & logistics | 2018 |
| Ambrose Trustees Limited | Financial services | 2008 |
| AMC Tax Consulting Ltd | Professional & scientific | 2020 |
| Amcag Consulting Limited | Professional & scientific | 2024 |
| Amcam Construction Ltd | Construction | 2017 |
| Amcam TV Ltd | Information & communication | 2010 |
| Amdepa Advisory Limited | Professional & scientific | 2024 |
| Amedwa Limited | Real estate | 2020 |
| Amelday Limited | Real estate | 2000 |
| Amethyst Sales & Lettings Limited | Real estate | 2007 |
| AMI Brow Bar Ltd | Other services | 2018 |
| AMI Business Consultants Ltd | Professional & scientific | 2012 |
| AMI Property Services Ltd | Real estate | 2021 |
| AMI Transport Ltd | Transport & logistics | 2014 |
| Amitom Trade Ltd | Wholesale & retail | 2018 |
| Amity Properties Ltd | Real estate | 2017 |
| AMK Transport Limited | Transport & logistics | 2016 |
| AML Welders Limited | Manufacturing | 2017 |
| Amman Trading Ltd | Real estate | 2012 |
| Ammore Limited | Wholesale & retail | 2024 |
| Amored Ltd | Professional & scientific | 2020 |
| Amorphe Consulting Limited | Information & communication | 2002 |
| Ample Force Drivers Limited | Transport & logistics | 2010 |
| Amsun IT Limited | Information & communication | 2022 |
| AMT Bespoke Homes Limited | Construction | 2016 |
| AMT Land Investments Limited | Real estate | 2016 |
| AMT Projects Construction Limited | Construction | 1999 |
| Amy&Teo Ltd | Transport & logistics | 2016 |