| Aiim International Limited | Other services | 1996 |
| Ainsworth-Parker Homes Ltd | Real estate | 2024 |
| Airstream Catering Ltd | Hospitality | 2019 |
| Aitken Productions Limited | Information & communication | 1998 |
| AJ Carpentry & Home Improvements Limited | Construction | 2025 |
| AJ Network Solutions Ltd | Information & communication | 2017 |
| AJG Actuarial Ltd | Financial services | 2017 |
| AJM (Evesham) Limited | Real estate | 2014 |
| AJM Limited | Extraterritorial | 2023 |
| AJM Property Partnership (UK) Limited | Real estate | 2017 |
| AJS Flooring Ltd | Construction | 2025 |
| AK Construction Consultancy Ltd | Professional & scientific | 2023 |
| Akash Training Agency Ltd | Administrative & support | 2017 |
| Akxellera Ltd | Wholesale & retail | 2024 |
| AL Ahmedy (U.K.) Limited | Other services | 2002 |
| Alamo Group Europe Limited | Professional & scientific | 1991 |
| Alan Wilks Scaffolding Limited | Construction | 2002 |
| Albert Plumbing and Heating Ltd | Construction | 2025 |
| Albert Road Dental Practice Limited | Health & social care | 2021 |
| Aldington Land Management Ltd | Real estate | 2003 |
| Alece Ltd | Transport & logistics | 2026 |
| Alex Johnson Technical Consulting Ltd | Information & communication | 2022 |
| Alex Trading Limited | Wholesale & retail | 2014 |
| Alex Woodwork Ltd | Construction | 2018 |
| Alexander Associates Limited | Administrative & support | 1995 |
| Alexander Bridges Talent Limited | Administrative & support | 2022 |
| ALI at Kueenshead Limited | Hospitality | 2026 |
| Alias LFD Ltd | Transport & logistics | 2024 |
| Align-Pilates Equipment Ltd | Wholesale & retail | 2014 |
| ALL About Travel Ltd | Administrative & support | 2015 |
| ALL Star Activities Ltd | Health & social care | 2012 |
| Allchurch Barnes Recruitment Limited | Administrative & support | 2014 |
| Allen Fabrications Finance Limited | Financial services | 2016 |
| Allen Fabrications Holdings Limited | Financial services | 2016 |
| Allen Fabrications Limited | Manufacturing | 1963 |
| Allen Fabrications Management Limited | Real estate | 2016 |
| Almswood Advisory Services Limited | Professional & scientific | 2014 |
| Alpha Brokers Services Ltd | Financial services | 2024 |
| Alpha Commercial Brokers Ltd | Financial services | 2025 |
| Alpha Fabrication Limited | Manufacturing | 2001 |
| Alpha Holdings (Worcestershire) Limited | Financial services | 2024 |
| Alqemi Ltd | Manufacturing | 2008 |
| Alta Business Improvements Ltd | Professional & scientific | 2015 |
| Alta Car and Engineering Company Limited | Extraterritorial | 2016 |
| Alumier Labs UK Limited | Wholesale & retail | 2018 |
| Alvr Ltd | Construction | 2025 |
| Amarasekara and Amarasekara Ltd | Health & social care | 2019 |
| Amarda Ltd | Households | 1998 |
| Amarilli Properties Limited | Real estate | 2023 |
| Amaryllis Ventures Limited | Professional & scientific | 2014 |
| Ambasador of Cleaning Service Ltd | Hospitality | 2021 |
| Ambassador Snooker Co Ltd | Hospitality | 2024 |
| Amds Consultants Limited | Professional & scientific | 2010 |
| AMF Cats Limited | Water & waste | 2010 |
| Amph Consulting Limited | Professional & scientific | 2019 |
| Anaconda Security Ltd | Administrative & support | 2026 |
| Anaesthetic Related Collaboration Ltd | Health & social care | 2024 |
| Andrei&Matei Trans Ltd | Transport & logistics | 2019 |
| Andrew Catmur Engineers Limited | Professional & scientific | 2016 |
| Andrew Granger & Co Ltd | Real estate | 2014 |
| Androck Limited | Administrative & support | 2023 |
| Andy 2021 Ltd | Transport & logistics | 2022 |
| Andy Chambers Limited | Construction | 2006 |
| Angel Vaults Evesham Ltd | Hospitality | 2025 |
| Animate Design Limited | Manufacturing | 2005 |
| Anne Elizabeth Strategies Ltd | Professional & scientific | 2025 |
| Annie's Homes Limited | Real estate | 2016 |
| Annie's HOMES2 Ltd | Real estate | 2021 |
| Anqa Publishing Limited | Information & communication | 2018 |
| Anthony James (Pattingham) Limited | Other services | 2023 |
| Anthony Welch Holdings Ltd | Financial services | 2024 |
| Anvi Medical Services Limited | Health & social care | 2012 |
| ANW Developments Limited | Real estate | 2026 |
| APA Construction Consultancy Limited | Professional & scientific | 2006 |
| Apex Advance Ltd | Education | 2025 |
| Apex Heating, Plumbing and GAS Systems Limited | Manufacturing | 2025 |
| APK Electrical Services Limited | Construction | 2011 |
| Apperley Honing Limited | Administrative & support | 1963 |
| Apperley Honing Machines Limited | Professional & scientific | 2006 |
| Appfuel Limited | Administrative & support | 2022 |
| Apple Planning and Design Ltd | Professional & scientific | 2021 |
| APT Vehicle Repairs Ltd | Wholesale & retail | 2017 |
| Aqua Clean (2022) Limited | Administrative & support | 2022 |
| Aqua Roofing Cheltenham Limited | Construction | 2025 |
| Aquaforte Solutions Limited | Manufacturing | 2026 |
| AR Partners Limited | Construction | 2014 |
| Ar&Em Ltd | Transport & logistics | 2020 |
| Ardcourt Limited | Professional & scientific | 2015 |
| Arditi Skate Ltd | Manufacturing | 2021 |
| Arenbe Limited | Administrative & support | 2017 |
| Arjun Construction Ltd | Construction | 2018 |
| ARP Alpha Limited | Construction | 2014 |
| ARP Carbon Limited | Professional & scientific | 2022 |
| Arpista Investments Limited | Real estate | 2025 |
| Arrowvale Investments Limited | Real estate | 2025 |
| Artemis Hotel Group Limited | Hospitality | 2017 |
| Artists in Exile Limited | Health & social care | 2022 |
| Arysta Lifescience Registrations Great Britain Limited | Professional & scientific | 2001 |
| ASD Holdings Limited | Financial services | 2026 |
| ASE Lettings Limited | Real estate | 2021 |