| Allegra Health Care Ltd | Health & social care | 2025 |
| Alliance MSP Limited | Administrative & support | 2022 |
| Almners Inc Ltd | Construction | 2025 |
| Aloeli Ltd | Construction | 2026 |
| Alon Services Ltd | Administrative & support | 2025 |
| Alpesh Patel Ltd | Extraterritorial | 2025 |
| Alpha Roofing and Home Improvements Ltd | Construction | 2025 |
| Alpha Universal Limited | Mining & quarrying | 2018 |
| Alto Cinco Ltd | Administrative & support | 2024 |
| AM Caravans Management Ltd | Real estate | 2021 |
| AM Caravans Transport Ltd | Transport & logistics | 2020 |
| AM Pizza and Chicken Ltd | Hospitality | 2019 |
| AM Warnajtys Ltd | Transport & logistics | 2023 |
| Amari Plastics Limited | Extraterritorial | 2017 |
| Amari Plastics Pension Trustees Limited | Extraterritorial | 1999 |
| Amathus Limited | Wholesale & retail | 1999 |
| Amaze Properties Limited | Real estate | 2006 |
| Amazing Healthcare and Recruitment Services Limited | Administrative & support | 2023 |
| Amberstone Property Holdings Ltd | Real estate | 2026 |
| Ambire Limited | Information & communication | 2018 |
| Amco Homes Ltd | Construction | 2015 |
| Amco Normandy Ltd | Construction | 2020 |
| Amdm Properties Ltd | Real estate | 2022 |
| Amesos Limited | Professional & scientific | 2013 |
| Amivie Signature Care Ltd | Health & social care | 2025 |
| Amps Property Ltd | Real estate | 2024 |
| ANA Global Ventures Limited | Wholesale & retail | 2025 |
| Anaik Trading Limited | Wholesale & retail | 2020 |
| Anderson Holdings (KRR) Limited | Professional & scientific | 2019 |
| Andrew John Bennett Limited | Arts & recreation | 2014 |
| Angela Technologies Limited | Information & communication | 2022 |
| Animatic Ltd | Professional & scientific | 2014 |
| Anisa Holdings London Ltd | Real estate | 2026 |
| Anna Wojciechowska Ltd | Wholesale & retail | 2019 |
| Annabel Jones Ltd | Administrative & support | 2015 |
| Annual Tax Return Ltd | Other services | 2015 |
| Antiqueforsale Limited | Extraterritorial | 2013 |
| Antony Edwards Surveyors Ltd | Professional & scientific | 2016 |
| Anwar Transport Limited | Transport & logistics | 2022 |
| AOA Capital Holdings Limited | Financial services | 2025 |
| AP Distribution Limited | Wholesale & retail | 2023 |
| Apex Roofing & Home Improvements Ltd | Construction | 2025 |
| Apollo Tax Solutions Limited | Professional & scientific | 2026 |
| Apotheplanner Ltd | Wholesale & retail | 2025 |
| App House Limited | Information & communication | 2016 |
| Applegrove Axiom Ltd | Professional & scientific | 2019 |
| AQ Riva DRY Cleaners Ltd | Other services | 2015 |
| Aqua Rangers Weybridge Ltd | Arts & recreation | 2013 |
| Aquatech Pools Limited | Manufacturing | 2006 |
| Aranathan Limited | Health & social care | 2020 |
| Arcturus Stem Ltd | Information & communication | 2022 |
| Arenaplane Limited | Financial services | 1999 |
| ARJ Property Investments Ltd | Real estate | 2016 |
| Arka Creative Limited | Information & communication | 2025 |
| Arkitectly Ltd | Professional & scientific | 2008 |
| Armfield Retail & Leisure Limited | Construction | 2006 |
| Arnold Associates Limited | Real estate | 2007 |
| Arow Media Limited | Professional & scientific | 2025 |
| ARP Logic IT Services Limited | Information & communication | 2018 |
| Artbel Limited | Wholesale & retail | 2015 |
| Artcome Limited | Public administration | 2024 |
| Artel Projects Limited | Real estate | 2013 |
| Artisan Garden Rooms Ltd | Construction | 2023 |
| Artizan Interiors Limited | Construction | 2009 |
| ASH Farm Estates Ltd | Real estate | 2025 |
| Ashill Commercial Ltd | Real estate | 2021 |
| Ashill Land Limited | Real estate | 2013 |
| Ashill Regen Limited | Real estate | 2021 |
| Ashill ZV Ltd | Real estate | 2024 |
| Asma Consultants Ltd | Information & communication | 2020 |
| ASR Estates (UK) Limited | Real estate | 2014 |
| Asset Management International Group Ltd | Information & communication | 2025 |
| Assist Solutions (UK) Limited | Manufacturing | 2009 |
| Assure Today Limited | Financial services | 2019 |
| AT OUR Best Ltd | Professional & scientific | 2015 |
| Atlify Ltd | Information & communication | 2022 |
| Atomic POP Ltd. | Wholesale & retail | 2011 |
| Audrey (London) Limited | Extraterritorial | 1961 |
| Audrey Investments Limited | Professional & scientific | 1940 |
| Aura AI Systems Limited | Information & communication | 2020 |
| Austin Reynolds Holdings Ltd | Financial services | 2026 |
| Austin Reynolds Limited | Wholesale & retail | 1990 |
| Austin Reynolds Site Safety Limited | Construction | 2001 |
| Austin Reynolds Special Projects Limited | Construction | 1998 |
| Auto Hub Bourne Ltd | Wholesale & retail | 2023 |
| Auto Trade Hub Ltd | Other services | 2019 |
| Autotest 2000 Limited | Wholesale & retail | 2008 |
| Auxero Limited | Information & communication | 2018 |
| Aviat International Ltd | Transport & logistics | 2016 |
| AX Customs Ltd | Wholesale & retail | 2020 |
| Aztec Photography Limited | Professional & scientific | 2011 |
| Azzurri Management Services Ltd | Professional & scientific | 2025 |
| B & S Associates UK Ltd | Professional & scientific | 2017 |
| B G I Supplies Limited | Other services | 2006 |
| B Hussey Limited | Wholesale & retail | 2025 |
| B.T.W. Scaffolding Limited | Construction | 1993 |
| Bakewell Properties Limited | Real estate | 2026 |
| Bankfoot Developments Limited | Real estate | 2016 |
| Barbican Square Limited | Construction | 2016 |
| Barkham Ride Finchampstead Ltd | Water & waste | 2024 |