| AGT Consultants Limited | Professional & scientific | 2020 |
| AGT Security Limited | Administrative & support | 2023 |
| AH Motorsport Consulting Limited | Professional & scientific | 2025 |
| Ahkhal Capital Holding Ltd | Financial services | 2025 |
| Ahkhal Ltd | Health & social care | 2021 |
| Ahuku Ltd | Wholesale & retail | 2018 |
| Ahwiiruntings Ltd | Wholesale & retail | 2024 |
| AI IT Tech Ltd | Information & communication | 2019 |
| AI UK IO Limited | Information & communication | 2023 |
| AI UK Systems Limited | Information & communication | 2023 |
| AI Ventura Ltd | Financial services | 2025 |
| AIA Accommodation Ltd | Real estate | 2025 |
| Aiden Love Limited | Other services | 2023 |
| Aiisiki Media Ltd | Information & communication | 2026 |
| Aimada Ltd | Construction | 2021 |
| Aimee-Leigh Irish Dance Academy Ltd | Arts & recreation | 2022 |
| Air Ambulance Aviation Ltd | Transport & logistics | 2026 |
| Air Ambulance Charity Kent Surrey Sussex | Health & social care | 1993 |
| Air Ambulance Promotions Limited | Wholesale & retail | 1991 |
| Air Environment Limited | Extraterritorial | 2005 |
| Airpack 2000 Property Holdings Limited | Real estate | 2026 |
| Airport Taxis of Medway Ltd | Transport & logistics | 2019 |
| Airsk Properties Ltd | Real estate | 2023 |
| Aivie Ltd | Health & social care | 2025 |
| Aiyekan Ltd | Wholesale & retail | 2021 |
| AJ Accounts and Taxation Limited | Professional & scientific | 2012 |
| AJ Hills Specialist Installations Limited | Construction | 2013 |
| AJ Repair Limited | Other services | 2021 |
| AJ Singh Properties Holdings Ltd | Financial services | 2026 |
| AJ Singh Properties Ltd | Real estate | 2024 |
| Aj's Building & Maintenance (Sussex) Ltd | Construction | 2025 |
| Ajai Limited | Health & social care | 2012 |
| Ajayi Okko Limited | Real estate | 2023 |
| Ajays Property Holdings Ltd | Real estate | 2022 |
| AJB Services South East Ltd | Construction | 2018 |
| AJD Motors Limited | Wholesale & retail | 2009 |
| AJD Motors MOT Ltd | Wholesale & retail | 2024 |
| Ajmadaptions Ltd | Construction | 2018 |
| Ajmr Ltd | Construction | 2026 |
| AJN Transport Ltd | Transport & logistics | 2026 |
| AK Dent Ltd | Health & social care | 2024 |
| AKH Maintenance & Cleaning Ltd | Construction | 2024 |
| Akhalu Care Limited | Health & social care | 2025 |
| Akinslameda Limited | Extraterritorial | 2023 |
| Akriss Properties Ltd | Real estate | 2024 |
| AKS Mechanical Limited | Administrative & support | 2017 |
| AL 2026 Limited | Real estate | 2025 |
| Al-De Property Ltd | Real estate | 2024 |
| Alade & Co. Ltd | Wholesale & retail | 2022 |
| Alan Robert Gough Ltd | Construction | 2011 |
| Alasco Management Limited | Administrative & support | 2020 |
| Albatross Carpentry Limited | Construction | 2005 |
| Albay Technologies Ltd | Information & communication | 2011 |
| Albion Retail Limited | Wholesale & retail | 2017 |
| Alborme Ltd | Real estate | 2022 |
| Aldridge Care Homes Ltd | Health & social care | 2014 |
| Alesi Marketing Ltd | Professional & scientific | 2026 |
| Alex Anthony Hairdressing Ltd | Other services | 2024 |
| Alex Woodhouse Carpentry Ltd | Construction | 2022 |
| Alexand Ltd | Health & social care | 2023 |
| Alexander James International Ltd | Real estate | 2020 |
| Alexovie & Co Ltd | Health & social care | 2020 |
| Alfa Electrical Services Limited | Other services | 2016 |
| Alicante Solutions UK Ltd | Administrative & support | 2025 |
| Aligncare Collective Ltd | Health & social care | 2025 |
| Alikama Fish Limited | Other services | 2025 |
| Alinestate Limited | Real estate | 2026 |
| Alkebulan Art Ltd | Education | 2024 |
| ALL 2 One Ltd | Wholesale & retail | 2023 |
| ALL Access Healthcare Limited | Health & social care | 2017 |
| ALL Build Property Limited | Real estate | 2024 |
| ALL Counties Commissioning Limited | Construction | 2011 |
| ALL Division Building Limited | Construction | 2013 |
| ALL Heights Scaffolding Services Ltd | Construction | 2025 |
| ALL Mech Pipework Limited | Construction | 2016 |
| ALL Rise UP CIC | Health & social care | 2024 |
| ALL Round Glazing Ltd | Construction | 2020 |
| ALL Saints Place Ltd | Real estate | 2025 |
| ALL Seasons Felt Roofing Ltd | Construction | 2014 |
| ALL Size Roofing Services Limited | Construction | 2009 |
| ALL Space Planning Ltd | Professional & scientific | 2025 |
| ALL Star Mobiles Ltd | Wholesale & retail | 2018 |
| ALL Sufficiency Ltd | Wholesale & retail | 2026 |
| ALL Technical Services Limited | Construction | 2020 |
| ALL the People Experience Limited | Wholesale & retail | 2025 |
| ALL Things Media Limited | Information & communication | 2013 |
| ALL Trades Interiors Limited | Construction | 2017 |
| All.In Property Investments Ltd | Real estate | 2025 |
| Allahu Akbar Limited | Health & social care | 2013 |
| Allens Hill Farms Limited | Administrative & support | 2006 |
| Allflow Connections Ltd | Construction | 2025 |
| Alliance Machine Services Ltd | Manufacturing | 2005 |
| Alliance Property Solutions Limited | Real estate | 2015 |
| Allied Build Sourcing & Supplies Ltd | Other services | 2019 |
| Alloys and Accessories Ltd | Wholesale & retail | 2026 |
| Allpure Services Ltd | Transport & logistics | 2024 |
| Allserv Facilities Management Limited | Other services | 2025 |
| Allserve Construction Ltd | Construction | 2010 |
| Allset Safety Training Limited | Administrative & support | 2011 |
| Allshifts Limited | Information & communication | 2024 |