| Adam Catering (London) Ltd | Hospitality | 2025 |
| Adam Law Shoemaker Ltd | Manufacturing | 2023 |
| Adam Lightowler & Sons Limited | Construction | 2014 |
| Adansiman Investments Ltd | Construction | 2016 |
| Adcentric Ltd | Professional & scientific | 2020 |
| Adeke IT Ltd | Other services | 2026 |
| Adeks Limited | Health & social care | 2014 |
| Adena Investments Limited | Real estate | 1963 |
| Adlink Communications Limited | Information & communication | 1999 |
| Admac Holdings Limited | Financial services | 2023 |
| Admac Limited | Professional & scientific | 1989 |
| Admiral Ventilation Ltd | Construction | 2023 |
| Adova Bedding Limited | Professional & scientific | 2018 |
| ADP Brickwork Ltd | Construction | 2026 |
| ADS Property & Management Ltd | Real estate | 2016 |
| Adunten Ltd | Health & social care | 2013 |
| Advanced Home Improvements S E Ltd | Construction | 2025 |
| Advanced Power Components Limited | Wholesale & retail | 2011 |
| Advanced Retractable Cables Limited | Manufacturing | 2004 |
| Advanced Therapeutic Massage & Mindworks Ltd | Education | 2026 |
| Advanced Trades Ltd | Professional & scientific | 2018 |
| Advanced-Passive Thermal Solutions Ltd | Manufacturing | 2025 |
| Advisor Hub Limited | Financial services | 2025 |
| AE Business Support Limited | Administrative & support | 2025 |
| AE Osteopathy Ltd | Health & social care | 2026 |
| Aegis AI Systems Limited | Information & communication | 2026 |
| AEL Bridge Ltd | Construction | 2019 |
| AEV Cleaning Ltd | Administrative & support | 2024 |
| Afes Holdings Limited | Real estate | 2025 |
| Affinity HR Services Ltd | Other services | 2014 |
| Affordable Cars of Kent Prep Centre Ltd | Wholesale & retail | 2023 |
| Affordable Cars of Kent, LLP | | 2007 |
| Affordable Scaffolding Limited | Construction | 2011 |
| AFI Roofing Ltd | Construction | 2025 |
| AFM Sports Limited | Wholesale & retail | 2010 |
| AFR Partners Ltd | Professional & scientific | 2022 |
| African Shop Ltd | Wholesale & retail | 2024 |
| AG Inventory Services Ltd | Real estate | 2020 |
| Agape Carpentry Ltd | Manufacturing | 2024 |
| Agar Bowles Ltd | Professional & scientific | 2021 |
| AGE Solutions Essex Ltd | Construction | 2024 |
| Ages Security Ltd | Administrative & support | 2025 |
| Agile Procurement Solutions Limited | Professional & scientific | 2018 |
| Agnostic Ltd | Real estate | 2019 |
| AGP Singh Ltd | Real estate | 2025 |
| Agravain Advisory Limited | Financial services | 2009 |
| AH Steel Services Ltd | Real estate | 2017 |
| AHY Training Solutions Ltd | Information & communication | 2024 |
| AI Accountancy Solutions Limited | Professional & scientific | 2025 |
| Aida Stefy Ltd | Transport & logistics | 2024 |
| Aidan Partners Ltd | Administrative & support | 2016 |
| Aindah Consultancy Ltd | Professional & scientific | 2023 |
| Air Quality Limited | Professional & scientific | 2015 |
| Airbourne Advisory Limited | Professional & scientific | 2023 |
| Aircool Systems (Southern) Limited | Construction | 2014 |
| Aircure Limited | Administrative & support | 2024 |
| Airfield (Christchurch) Industrial Estate Management Limited | Real estate | 1980 |
| Airgard-Uv Ltd | Other services | 2021 |
| Airpacks Ltd. | Manufacturing | 1990 |
| Aithrivio Ltd | Information & communication | 2026 |
| Aiverse Ltd | Information & communication | 2025 |
| AJ Coaching Ltd | Arts & recreation | 2025 |
| AJ Supertrans Limited | Transport & logistics | 2025 |
| AJA Construction Group Limited | Construction | 2017 |
| AJA Holdings Limited | Real estate | 2008 |
| AJC Scaffolding Ltd | Construction | 2021 |
| AJD Corporation Limited | Education | 2024 |
| Ajheslehurst Ltd | Information & communication | 2002 |
| AJM Commerce Ltd | Wholesale & retail | 2025 |
| AJN & Co Ltd | Professional & scientific | 2012 |
| AJS & Sons Electrical Services Ltd | Construction | 2021 |
| AJV Homes Limited | Real estate | 2025 |
| AK Tax & Accountancy Ltd | Professional & scientific | 2011 |
| AK Transport (BG) Limited | Transport & logistics | 2015 |
| Ak&J Services Ltd | Administrative & support | 2021 |
| Akaal & Roops Ltd | Real estate | 2016 |
| Akce Group Limited | Financial services | 2024 |
| Akehurst Plumbing and Heating Ltd | Construction | 2025 |
| Akinola Foods Strood Limited | Wholesale & retail | 2023 |
| Akis Group Ltd | Real estate | 2023 |
| Akçe Capital Limited | Information & communication | 2024 |
| Al's & Sal's Ltd | Hospitality | 2019 |
| Alan C Bennett & Sons Limited | Transport & logistics | 1984 |
| Albemarle Graphics Limited | Administrative & support | 1977 |
| Albert Group Holdings Limited | Other services | 2025 |
| Albertini Ltd | Education | 2015 |
| Albertus Café Limited | Hospitality | 2026 |
| Albertus Investments Limited | Real estate | 2024 |
| Alco Plant Hire Limited | Transport & logistics | 1971 |
| Aldgate Advice Limited | Wholesale & retail | 2023 |
| Aldworth Mansions Limited | Real estate | 2003 |
| Aled Limited | Administrative & support | 2004 |
| Aleksha Care Limited | Health & social care | 2019 |
| Aleksha Holdings Ltd | Financial services | 2024 |
| Alex Olsen Racing Ltd | Arts & recreation | 2020 |
| Alex Works Ltd | Transport & logistics | 2022 |
| Alexander Blacker Management Ltd | Construction | 2018 |
| Alexander Jackman Holdings Limited | Construction | 2022 |
| ALF Brand Name Services Limited | Professional & scientific | 2022 |
| Alf-Rhodes Limited | Professional & scientific | 2012 |