| Alfa Cleaning & Hygiene Supplies Ltd | Wholesale & retail | 2010 |
| Alfa Cooling Ltd | Manufacturing | 2023 |
| Alfred's Court Management Company Ltd | Households | 2017 |
| Algorithmic Studio Limited | Professional & scientific | 2022 |
| Aliance Recovery Limited | Wholesale & retail | 2026 |
| ALL Trades South East Limited | Construction | 2020 |
| Allday PAY Limited | Administrative & support | 2003 |
| Allday Time Systems (Holdings) Limited | Financial services | 2025 |
| Allday Time Systems Limited | Manufacturing | 2000 |
| Allen Glanville Holdings Limited | Real estate | 1951 |
| Allister Group Construction Ltd | Construction | 2024 |
| Almighty Electrical Services Ltd | Construction | 2019 |
| Almitech Limited | Professional & scientific | 2020 |
| Aloomah Limited | Information & communication | 2025 |
| Alpha Landscaping Solutions Ltd | Administrative & support | 2021 |
| Alpha Roof Repairs and Gutters Limited | Construction | 2023 |
| Alpha Same Day Roofing Ltd | Construction | 2026 |
| Alpha Seamless Guttering Limited | Construction | 2020 |
| Alpha SG Limited | Construction | 2026 |
| Alpha Solar Panel Experts Ltd | Other services | 2022 |
| Alphabet (GB) Limited | Financial services | 1996 |
| Alphazure Ltd | Information & communication | 2019 |
| Alpine Logistic Services Ltd | Transport & logistics | 2024 |
| Altair Engineering Limited | Information & communication | 1995 |
| Altamont (Warlingham) Freeholders Ltd | Households | 2008 |
| Altaris Consulting Ltd | Professional & scientific | 2026 |
| Alternative Cleaning Ltd | Administrative & support | 2001 |
| Alton Martial Arts Academy Ltd | Arts & recreation | 2018 |
| AM Compliance Consulting Limited | Information & communication | 2023 |
| AM Dreams Ltd | Manufacturing | 2025 |
| AM Industrial (UK) Limited | Manufacturing | 2007 |
| AM Sports Events Ltd | Arts & recreation | 2026 |
| Amarisa Media Ltd | Information & communication | 2021 |
| AMG Electrical Ltd | Construction | 2020 |
| Amirkhani Consultancy Ltd | Administrative & support | 2024 |
| Ammira Ltd | Manufacturing | 2023 |
| Amor Phatty Ltd | Wholesale & retail | 2025 |
| AMP Busbar Installations Ltd | Construction | 2024 |
| Amphora Topco Limited | Information & communication | 2011 |
| AMR Couriers Ltd | Transport & logistics | 2010 |
| AMS Group (London) Limited | Professional & scientific | 2019 |
| AMS Medical Health Ltd | Health & social care | 2018 |
| AMS Property Holdings Limited | Real estate | 2026 |
| Amun RA Online Ltd | Other services | 2025 |
| AN & MI Ltd | Transport & logistics | 2026 |
| Anaut UK Ltd | Manufacturing | 2026 |
| Anchor and Arrow Limited | Professional & scientific | 2025 |
| Anchor Property Limited | Real estate | 2019 |
| Anderson Roofing Supplies Ltd | Administrative & support | 2002 |
| Anderson Roofline Ltd | Construction | 2022 |
| Andrea Baker Consulting Limited | Extraterritorial | 2021 |
| Andreani UK Ltd | Wholesale & retail | 2026 |
| Andrews Financial Ltd | Financial services | 2009 |
| Angelic by Design Ltd. | Other services | 2013 |
| Animatus Europroductions Limited | Information & communication | 2004 |
| Anis Investments PVT Ltd | Health & social care | 2011 |
| ANK Environmental Consultancy Ltd | Professional & scientific | 2007 |
| Anker Services Limited | Construction | 2025 |
| Anna K Property Ltd | Real estate | 2023 |
| Annapurna Catering Limited | Hospitality | 2020 |
| Anotidaishe Care Limited | Health & social care | 2022 |
| Ansa Food & Wine Limited | Wholesale & retail | 2020 |
| Antko Electrical Ltd | Construction | 2014 |
| Anytime Clubs UK Limited | Arts & recreation | 2010 |
| Anywhere Film Ltd | Arts & recreation | 2019 |
| Aoife Hastings Design Ltd | Professional & scientific | 2022 |
| Aolunmei Limited | Hospitality | 2019 |
| AON Consulting Financial Services Limited | Professional & scientific | 1950 |
| AON Consulting Limited | Professional & scientific | 1995 |
| AP Build Limited | Construction | 2017 |
| AP Show Logistics Limited | Transport & logistics | 2010 |
| Apad Exchange Limited | Information & communication | 2017 |
| APC Building Group Limited | Construction | 2024 |
| Apex Building Products Ltd | Manufacturing | 2007 |
| Apex Drywall Interiors Ltd | Construction | 2026 |
| Apothelink Ltd | Information & communication | 2026 |
| Apple Clean Facilities Ltd | Administrative & support | 2018 |
| Apple Clean Solutions Ltd | Administrative & support | 2024 |
| Apple Nail 3 & Beauty Ltd | Other services | 2026 |
| Approved Autos Limited | Other services | 2008 |
| Apron Consulting Ltd | Transport & logistics | 2016 |
| Aquability (UK) Limited | Wholesale & retail | 1994 |
| Aquarius Commissioning Solutions Ltd | Professional & scientific | 2020 |
| AR Stunts Ltd | Arts & recreation | 2021 |
| Aravco Limited | Transport & logistics | 1977 |
| Arbor Walk (Cuckfield) Management Company Ltd | Households | 2015 |
| ARC Phoenix Ltd | Information & communication | 2020 |
| Arcadia IT Services Ltd | Information & communication | 2026 |
| Archibald Consulting Ltd | Professional & scientific | 2024 |
| ARJ Media Ltd | Information & communication | 2021 |
| Arjun & SON Ltd | Transport & logistics | 2014 |
| Arjunpuspa Properties Ltd | Real estate | 2022 |
| Arkado Ltd | Information & communication | 2021 |
| Arktech IT Solutions Ltd | Information & communication | 2022 |
| Armour IT Ltd | Hospitality | 2008 |
| Arms Reliability Europe LLP | | 2012 |
| Arnek Cooling Ltd | Manufacturing | 2022 |
| Arnella Court Management Company Limited | Households | 1988 |
| ARO Dynamics Limited | Transport & logistics | 2012 |
| Artashobby Ltd | Wholesale & retail | 2025 |