| ALL WE DO IS Care Ltd | Health & social care | 2026 |
| ALL Weatherproof Roofing Ltd | Construction | 2026 |
| All-Right Accountancy Services Ltd | Professional & scientific | 2022 |
| Allbio Limited | Professional & scientific | 2014 |
| Allclout UK Ltd | Financial services | 2020 |
| Allen Apprenticeships and Skills Limited | Administrative & support | 2016 |
| Allen Investment Group Ltd | Professional & scientific | 2023 |
| Alliance Family Mediation Ltd | Professional & scientific | 2024 |
| Alliance Roofing Contractors Ltd | Construction | 2024 |
| Allied F S Holdings Ltd | Financial services | 2022 |
| Allied Financial Services Limited | Financial services | 2004 |
| Allington House Right to Manage Company Limited | Households | 2025 |
| Alloydeck Pro Remediations Ltd | Construction | 2026 |
| Allport Cars (Kent) Ltd | Transport & logistics | 2018 |
| Alltoodev Limited | Information & communication | 2019 |
| Alluxi Consulting Limited | Professional & scientific | 2015 |
| Allways Freight UK Limited | Transport & logistics | 2003 |
| ALM Catering Kent Ltd | Hospitality | 2025 |
| Almners Road 1961 Limited | Extraterritorial | 2014 |
| Almo Construction Ltd | Construction | 2009 |
| Almodular Limited | Professional & scientific | 2023 |
| Almsrupiah Ltd | Health & social care | 2025 |
| Alnawfara Ltd | Construction | 2025 |
| Alpha ADE Homes Ltd | Real estate | 2023 |
| Alpha Care Residential Ltd | Health & social care | 2025 |
| Alpha Conservatories Limited | Construction | 2002 |
| Alpha Credit Consultants Limited | Financial services | 2000 |
| Alpha Financial Experts Limited | Financial services | 2020 |
| Alpha Technical Group Ltd | Construction | 2025 |
| Alphafeops Ltd | Information & communication | 2026 |
| Alphanics Ltd | Information & communication | 2020 |
| Alphapunk Limited | Information & communication | 2010 |
| Alpine Pharmaceuticals Ltd | Health & social care | 2022 |
| Alpita Properties Limited | Real estate | 2016 |
| Alsa Path Ltd | Administrative & support | 2023 |
| ALTA8 Limited | Manufacturing | 2016 |
| Altay AI Ltd | Professional & scientific | 2024 |
| Altay Technology Ltd | Arts & recreation | 2025 |
| Altered Creations Limited | Information & communication | 2021 |
| Alternative Water Supply Company Limited | Professional & scientific | 2008 |
| Altra Capital Limited | Professional & scientific | 2007 |
| Altus Shopfitters Ltd | Manufacturing | 2021 |
| Alufem Ltd | Wholesale & retail | 2026 |
| Alvah Limited | Financial services | 2023 |
| Alyas International Enterprise Ltd | Construction | 2016 |
| AM Construction Cost Management Ltd | Professional & scientific | 2019 |
| AM Contracting Ltd | Water & waste | 2025 |
| AM Development Consultants Limited | Hospitality | 2016 |
| AMA Properties Investment Ltd | Real estate | 2025 |
| Amaan Chauffeurs Limited | Transport & logistics | 2024 |
| Amac Records & Manufacturing Ltd | Manufacturing | 2024 |
| Amadale Capital LLP | | 2009 |
| Amadryas Sparky Limited | Administrative & support | 2019 |
| Amalon Services Limited | Wholesale & retail | 2019 |
| Aman City Wall Limited | Wholesale & retail | 2025 |
| Amana Home Care Ltd | Health & social care | 2025 |
| Amanurag Smile Services Ltd | Health & social care | 2023 |
| Amarilla Properties Ltd | Real estate | 2022 |
| Amazing Brewery Limited | Hospitality | 2015 |
| Amazing Comfort Care Limited | Public administration | 2025 |
| AMB Group Holdings Ltd | Financial services | 2023 |
| AMB Property Plus Ltd | Real estate | 2023 |
| Amba TAP Ltd | Administrative & support | 2019 |
| Amber Green Education Limited | Education | 2009 |
| Ambereen Malik Ltd | Professional & scientific | 2016 |
| Amberley Parks Limited | Real estate | 2015 |
| Amberset Limited | Manufacturing | 1996 |
| Amberstone Building Solutions Limited | Construction | 2025 |
| Ambrium Ltd | Information & communication | 2017 |
| Ambrose Change Consultancy Ltd | Administrative & support | 2015 |
| Ambrose Lettings Ltd | Real estate | 2020 |
| AMC Online Limited | Wholesale & retail | 2008 |
| AME Holdings Ltd | Real estate | 2024 |
| Ameliorate Carpentry & Fire Door Services Limited | Construction | 2021 |
| Ameltra Group Ltd | Financial services | 2026 |
| Ameno Properties Limited | Real estate | 2007 |
| Amerivita Ltd | Wholesale & retail | 2024 |
| Ames Mechanical Ltd | Construction | 2016 |
| Amesk Limited | Health & social care | 2009 |
| Amethyst Engineering Limited | Professional & scientific | 2016 |
| Amethyst Therapies Ltd | Other services | 2024 |
| Ametrine Holistics Ltd | Health & social care | 2015 |
| AMG Design & Development Ltd | Construction | 2026 |
| Amgs Leisure Limited | Arts & recreation | 2020 |
| Ami's Beauty & Aesthetics Ltd | Other services | 2022 |
| Amici South East Limited | Hospitality | 2014 |
| Amicus Legal Consultants Limited | Professional & scientific | 2008 |
| Amintha Ltd | Wholesale & retail | 2026 |
| AMJ IT Limited | Information & communication | 2011 |
| Amjh Ltd | Information & communication | 2018 |
| AMM Accountants Limited | Professional & scientific | 2024 |
| Ammar Tyres Ltd | Wholesale & retail | 2024 |
| Ammeld Consulting Ltd | Professional & scientific | 2023 |
| Ammg Shippers Limited | Wholesale & retail | 2022 |
| Ammuandmallu Ltd | Health & social care | 2022 |
| AMN Calibrate Ltd | Education | 2024 |
| Ampearson Electrical Ltd | Construction | 2021 |
| Amphoenix Capital Ltd | Administrative & support | 2024 |
| Amplio Technologies Ltd | Professional & scientific | 2020 |
| Ampm Traffic Management Ltd | Construction | 2026 |