| Alix Guichard Ltd | Information & communication | 2024 |
| Alkauthar Foundation Limited | Education | 2009 |
| ALL Handyman Services Limited | Construction | 2022 |
| ALL Shape Roofing Ltd | Construction | 2022 |
| All-X Online Ltd | Wholesale & retail | 2019 |
| Alldaymaintenance Ltd | Construction | 2019 |
| Allegro Star Ltd | Wholesale & retail | 2025 |
| Allied Construction & Housing Limited | Construction | 2008 |
| Allied Construction Trading Ltd | Construction | 2019 |
| Allium Ltd | Wholesale & retail | 2015 |
| Allpas Ltd | Professional & scientific | 2025 |
| Allsortsbuilders Limited | Construction | 2025 |
| Allspire Learning Ltd | Education | 2026 |
| Allulwa Ltd | Construction | 2026 |
| Almy Investment Ltd | Financial services | 2018 |
| Almys Holding Ltd | Financial services | 2021 |
| Almys Property Investment Ltd | Real estate | 2021 |
| Alnoor Consultants Limited | Wholesale & retail | 2012 |
| Alpha Design & Build Limited | Construction | 2003 |
| Alpha Information Systems Limited | Wholesale & retail | 2024 |
| Alpha MAX Trading Ltd | Hospitality | 2022 |
| Alpha Omega Pack UK Limited | Manufacturing | 2024 |
| Alpha Smart Controls UK Ltd | Construction | 2024 |
| Alpha Tech Solutions Ltd | Wholesale & retail | 2025 |
| Alpha UK Trading Limited | Wholesale & retail | 2022 |
| Alpha Zeta Law Ltd | Professional & scientific | 2025 |
| Alpha-Crete Concepts Limited | Construction | 2025 |
| ALR Asset Management Ltd | Real estate | 2022 |
| ALR Investments Ltd | Real estate | 2017 |
| ALR Realty Limited | Real estate | 2021 |
| ALS Trading London Ltd | Transport & logistics | 2021 |
| Altalena Properties Ltd | Real estate | 2025 |
| ALVI6663 Services Ltd | Transport & logistics | 2024 |
| Always Inside Group Ltd | Professional & scientific | 2022 |
| AM Squared Properties Ltd | Real estate | 2026 |
| AM2016 Trading Ltd | Transport & logistics | 2016 |
| Amaana Education Ltd | Health & social care | 2026 |
| Amaani London Trading Ltd | Wholesale & retail | 2018 |
| Amalaya Limited | Administrative & support | 2017 |
| Amaprint Limited | Real estate | 1996 |
| Amara Homes Limited | Health & social care | 2015 |
| Amara Limited | Wholesale & retail | 2004 |
| Amayes Ltd | Health & social care | 2023 |
| Amazing Donuts Ltd | Construction | 2014 |
| Amaztech Solutions Limited | Information & communication | 2011 |
| Ambacpdp Holding Ltd | Financial services | 2026 |
| Amber Orange Limited | Real estate | 2020 |
| Amber Property Real Estate Ltd | Real estate | 2024 |
| Ambient Forge Limited | Professional & scientific | 2021 |
| Ambient Shutters Ltd | Wholesale & retail | 2023 |
| Amcl Services Ltd | Construction | 2016 |
| AMD London Trading Ltd | Transport & logistics | 2021 |
| Ameer Trading Limited | Transport & logistics | 2024 |
| Amer Medicare Limited | Health & social care | 2015 |
| Amercybersec Ltd | Information & communication | 2020 |
| Ameur Property Management Services Limited | Hospitality | 2024 |
| AMH Trading London Ltd | Wholesale & retail | 2022 |
| Amhak Limited | Wholesale & retail | 2011 |
| Amigos Feliz Ltd | Wholesale & retail | 2014 |
| Amini Enterprises Ltd | Wholesale & retail | 2022 |
| Amir Rana Metals Trading LP | | 2012 |
| AML Construction Limited | Construction | 2023 |
| AMO Housing Ltd | Construction | 2025 |
| Ampra Limited | Health & social care | 2012 |
| Amros Property Ltd | Real estate | 2022 |
| Amsel Leathers Limited | Manufacturing | 2025 |
| AMV Accounting Limited | Professional & scientific | 2016 |
| AMY Investments Limited | Real estate | 2024 |
| AMY Judd Art Limited | Arts & recreation | 2014 |
| AN Global Trade Ltd | Other services | 2025 |
| Analyst International News Ltd | Other services | 2023 |
| Anaya's World Ltd | Hospitality | 2022 |
| Anbice Education Ltd | Education | 2025 |
| Ancaciprian Limited | Other services | 2018 |
| Anderson & Clark Ltd | Administrative & support | 2018 |
| Andlar Technologies Ltd | Information & communication | 2023 |
| Andrea Byrne Limited | Arts & recreation | 2003 |
| Andrologist Ltd | Information & communication | 2025 |
| Aneeka Property Investment Ltd | Real estate | 2019 |
| Anerley Park Ltd | Real estate | 2008 |
| Aneta Interiors Stylist Limited | Other services | 2025 |
| Aneugene Limited | Health & social care | 2011 |
| Angel Road Property Group Ltd | Professional & scientific | 2026 |
| Angelica Holdings Limited | Other services | 2016 |
| Angeline Morden Ltd | Other services | 2020 |
| Angels Connexions Ltd | Transport & logistics | 2017 |
| Anglo Design Limited | Wholesale & retail | 1995 |
| ANH Traders Ltd | Real estate | 2023 |
| Anicres Traders Ltd | Wholesale & retail | 2018 |
| Anikam Ltd | Real estate | 2021 |
| Anna Huix Ltd | Professional & scientific | 2016 |
| Annolloy Limited | Manufacturing | 1953 |
| Anoohads Limited | Transport & logistics | 2021 |
| ANS Health Care Ltd | Health & social care | 2023 |
| Ansiya Limited | Professional & scientific | 2026 |
| Antares Consulting Services Ltd | Administrative & support | 2020 |
| Anthonys Carpentry & Joinery Ltd | Manufacturing | 2025 |
| Anuven UK Limited | Health & social care | 2025 |
| ANW London Ltd | Transport & logistics | 2021 |
| Anwar UNI Traders Ltd | Wholesale & retail | 2024 |