| Aliom Holdings Limited | Financial services | 2014 |
| Alisim Limited | Health & social care | 2024 |
| ALK Consultancy Services Limited | Professional & scientific | 2024 |
| ALL Aspect Gardening Ltd | Administrative & support | 2025 |
| ALL BIN Solutions Ltd | Administrative & support | 2021 |
| ALL Build Contractors Ltd | Construction | 2010 |
| ALL Cozy? Ltd | Construction | 2018 |
| ALL Ears! Independent Hearing Specialists Ltd | Extraterritorial | 2025 |
| ALL FIX Plumbing Limited | Construction | 2016 |
| ALL Flutes Plus Limited | Wholesale & retail | 2021 |
| ALL Hazards Group Ltd | Education | 2018 |
| ALL Infrastructure Services LLP | | 2012 |
| ALL Loads Limited | Water & waste | 2006 |
| ALL MIX Kent Ltd | Manufacturing | 2013 |
| ALL Round Therapy Ltd | Public administration | 2018 |
| ALL Round Town Garden and Property Maintenance Ltd | Administrative & support | 2024 |
| ALL Safe Trans Ltd | Transport & logistics | 2026 |
| ALL Seasons Commercial (UK) Ltd | Administrative & support | 2024 |
| ALL Seasons Glamping Ltd | Extraterritorial | 2017 |
| ALL Small Loads Ltd | Water & waste | 2020 |
| ALL Star Couriers Ltd | Transport & logistics | 2019 |
| ALL Things Paws Limited | Other services | 2022 |
| ALL Vehicle Servicing Ltd | Wholesale & retail | 2024 |
| ALL YOU Need Wedding Styling Ltd | Administrative & support | 2023 |
| Allan Underdown Building Services Ltd | Construction | 2015 |
| Allan White Trading Limited | Construction | 1987 |
| Allcars Chart Sutton Ltd | Wholesale & retail | 2012 |
| Allen Mansions Limited | Households | 1984 |
| Allgains Limited | Information & communication | 2025 |
| Allgigs Limited | Information & communication | 2004 |
| Alliance Coordination Ltd | Professional & scientific | 2024 |
| Alliance Document Systems Limited | Information & communication | 2012 |
| Alliance Solutions Group Limited | Information & communication | 2004 |
| Alliance Solutions Limited | Information & communication | 2000 |
| Alliance Support Limited | Information & communication | 2004 |
| Alliance Trade Services Ltd | Administrative & support | 2015 |
| Alliance Works Ltd | Real estate | 2024 |
| Allied Luptons Limited | Professional & scientific | 2001 |
| Allingtan Ltd | Other services | 2024 |
| Allington Community Association Limited | Wholesale & retail | 2001 |
| Allington Marina Limited | Transport & logistics | 1963 |
| Allmand RTM Company Limited | Households | 2021 |
| ALM Productions LLP | | 2012 |
| Almeida Ribau Medical Ltd | Health & social care | 2015 |
| Almond Save Limited | Wholesale & retail | 2018 |
| Alnik Trans Limited | Transport & logistics | 2015 |
| ALO Advisory Ltd | Real estate | 2023 |
| ALP Professional Services Ltd | Construction | 2015 |
| Alpha Build Ltd | Administrative & support | 2009 |
| Alpha Developments (Kent) Limited | Real estate | 2023 |
| Alpha Fiber Food Ltd | Manufacturing | 2026 |
| Alpha Omega Arms Ltd | Manufacturing | 2022 |
| Alpha Partitions Ltd | Construction | 2024 |
| Alpha Projects (South East) Ltd | Construction | 2020 |
| Alpha Windows (Kent) Limited | | 1979 |
| Alphacars Rides Ltd | Transport & logistics | 2025 |
| Alphacircuit Ltd | Wholesale & retail | 2025 |
| Alphacrest Limited | Wholesale & retail | 2010 |
| Alpine Commercial Cleaning Limited | Administrative & support | 2011 |
| Alpine Design Limited | Professional & scientific | 2017 |
| Alpine Garage Limited | Wholesale & retail | 2014 |
| Alps (Deniz) Plumbing & Heating Ltd | Construction | 2025 |
| ALS Invest Limited | Extraterritorial | 2025 |
| Alsaya Limited | Wholesale & retail | 2022 |
| Alta Costura Ltd | Wholesale & retail | 2010 |
| Alta Holdings Ltd | Real estate | 2026 |
| Alta Pro Limited | Real estate | 2022 |
| Alter Space Technologies Ltd | Manufacturing | 2026 |
| Alterchrome Services Limited | Administrative & support | 2010 |
| Alterion Consulting Limited | Professional & scientific | 2010 |
| Altitec Limited | Manufacturing | 2001 |
| Altitude Building Services Ltd | Construction | 2025 |
| Altmen Real Estate Ltd | Real estate | 2021 |
| Altruist Healthcare Ltd | Health & social care | 2023 |
| Altryte Limited | Professional & scientific | 2004 |
| Altu Leader Ltd | Information & communication | 2025 |
| Alula Solutions Limited | Administrative & support | 2017 |
| Always Friday Ltd | Hospitality | 2025 |
| AM Selaru Limited | Transport & logistics | 2017 |
| AM Surveying Property Services Limited | Real estate | 2007 |
| Amacel Concept Ltd | Health & social care | 2022 |
| Amanda Greenland Inventories Limited | Households | 2026 |
| Amanda Homes Ltd | Real estate | 2018 |
| Amani Advisors & Contractors Ltd | Professional & scientific | 2012 |
| Amantia Holdings Limited | Financial services | 2025 |
| Amar Jones Limited | Professional & scientific | 2010 |
| Amaraspaces Ltd | Real estate | 2025 |
| Amass Trading Limited | Financial services | 2012 |
| Amaze Flooring Limited | Construction | 2025 |
| Amazegoods Ltd | Wholesale & retail | 2024 |
| AMB Optical Limited | Health & social care | 2016 |
| Amber Court Freehold Ltd | Real estate | 2026 |
| Amber Lily Limited | Financial services | 2021 |
| Amberfield Services Ltd | Professional & scientific | 2017 |
| Amck Properties Ltd | Real estate | 2021 |
| Amcore Media Limited | Information & communication | 2023 |
| Amelia Aldred Beauty Limited | Other services | 2025 |
| Amelia Art Glass Ltd | Wholesale & retail | 2010 |
| Amelias Closet Nails & Beauty Ltd | Other services | 2025 |
| Amenity Training and Consultancy Limited | Professional & scientific | 2021 |