| Acquire Mortgages Ltd | Financial services | 2018 |
| Active Apprentice Limited | Education | 2016 |
| Adam Sewell Media Ltd | Professional & scientific | 2021 |
| Adam Southern Developments Ltd | Construction | 2019 |
| Adamas Holdings Ltd | Real estate | 2021 |
| Adapt Air LLP | | 2024 |
| Adaptive Traffic Consulting Ltd | Professional & scientific | 2023 |
| Addtech Petroleum Corporation Limited | Wholesale & retail | 2011 |
| Addtek Properties Limited | Real estate | 2004 |
| Advance Minibuses Limited | Transport & logistics | 2011 |
| Advance PM Ltd | Construction | 2017 |
| Advance Your PAY Limited | Information & communication | 2020 |
| Advanced & Basic Medical Services Ltd | Health & social care | 2018 |
| Aerial Vision Surveys Ltd | Administrative & support | 2016 |
| Aerostocks Limited | Extraterritorial | 2016 |
| Aevum Longevity Clinic Limited | Health & social care | 2025 |
| Affix Services Ltd | Construction | 2025 |
| Agility Attire Ltd | Wholesale & retail | 2025 |
| Agius Group Ltd | Wholesale & retail | 2025 |
| Agodecott Ltd | Financial services | 2021 |
| AHB Iris Limited | Financial services | 2013 |
| AHF Property Limited | Real estate | 2021 |
| AIP Advisors Ltd | Households | 2026 |
| Air Vision Surveys Ltd | Administrative & support | 2016 |
| Aixr Ltd | Information & communication | 2023 |
| Aixr Management Limited | Information & communication | 2016 |
| AJ Construction Essex Ltd | Construction | 2022 |
| AJ Radiology and Imaging Services Ltd | Health & social care | 2022 |
| Aj&Sons Waste Removel Service Ltd | Water & waste | 2023 |
| AJA Training Services Ltd | Construction | 2025 |
| AJF Essex Limited | Hospitality | 2016 |
| AJN Trade Ltd | Wholesale & retail | 2026 |
| AJP Electrical Engineering Ltd | Construction | 2016 |
| AK Employment Tax Services Limited | Professional & scientific | 2017 |
| Alameda Advisory Limited | Professional & scientific | 2026 |
| Albon Engineering and Manufacturing Limited | Manufacturing | 1973 |
| Albon Forge Ltd | Manufacturing | 2019 |
| Alert Security Services Limited | Arts & recreation | 1989 |
| Alessandra Zorzato Limited | Administrative & support | 2026 |
| Alex Nesling Limited | Hospitality | 2003 |
| Alexander James & Co OIL & GAS Recruitment Ltd | Professional & scientific | 2007 |
| ALL Admin Assistance Ltd | Administrative & support | 2021 |
| ALL Clean London Limited | Administrative & support | 2011 |
| ALL in One Property Services Limited | Construction | 2003 |
| ALL Size Moves Ltd | Transport & logistics | 2025 |
| Allard Management LLP | | 2013 |
| Allet Scaffolding and Hire Limited | Construction | 2019 |
| Alliance Install Ltd | Construction | 2022 |
| Allington Electrical Ltd | Construction | 2018 |
| Alltheas Digital Services Ltd | Information & communication | 2024 |
| Alpha Omega Fleet Services Ltd | Wholesale & retail | 2021 |
| Alphabet Photography Shows UK Limited | Wholesale & retail | 2009 |
| Alphadigital Limited | Information & communication | 2017 |
| Alternative Estates Limited | Real estate | 2011 |
| Altra Group Limited | Wholesale & retail | 2025 |
| AM Electrical Group Ltd | Construction | 2022 |
| Amanda Yoga Retreats Limited Limited | Professional & scientific | 2019 |
| Amano Build Clean Ltd | Construction | 2020 |
| Amaziah Developments Ltd | Construction | 2026 |
| Amberg Constructions Ltd | Construction | 2023 |
| Amberg Ltd | Wholesale & retail | 2022 |
| Amberg Properties Ltd | Real estate | 2025 |
| Ambergate Properties Limited | Real estate | 2001 |
| Ambertec (M & E) Limited | Construction | 2006 |
| Ambia Construction Limited | Construction | 2023 |
| AMC Alliance Ltd | Real estate | 2022 |
| Amelco UK Limited | Information & communication | 2006 |
| Amenz Eco Engineering Ltd | Professional & scientific | 2015 |
| Amhill Financial Limited | Financial services | 2025 |
| Amikesh Ltd | Real estate | 2024 |
| Amira Enterprise Ltd | Hospitality | 2018 |
| Amjak Solutions Ltd | Professional & scientific | 2017 |
| Amour Children’S Homes Limited | Health & social care | 2025 |
| AMS Mortgage and Protection Ltd | Financial services | 2018 |
| AMY Morris Consulting Ltd | Professional & scientific | 2026 |
| Anahata the Heart of Therapies Limited | Health & social care | 2017 |
| Anarchy Media Limited | Information & communication | 2012 |
| Andarta Limited | Administrative & support | 2013 |
| Anderson Driver Hire Limited | Transport & logistics | 2020 |
| Andrew Barnes Consulting Limited | Professional & scientific | 2023 |
| Anikavi Limited | Information & communication | 2025 |
| Annwood Estates Ltd | Extraterritorial | 2008 |
| Anso Sells Ltd. | Wholesale & retail | 2025 |
| Anthony Simpson Limited | Construction | 2007 |
| Anti Ligature Direct Ltd | Wholesale & retail | 2015 |
| Antipasto by the Sea Limited | Hospitality | 2021 |
| Anvilware Ltd | Information & communication | 2023 |
| Anymeters.Co.Uk Ltd | Manufacturing | 2021 |
| Anywhere Fire Inspections Ltd | Public administration | 2023 |
| AOL Management Limited | Financial services | 2014 |
| Apex Cycles Ltd | Wholesale & retail | 2026 |
| Apex Decorators Limited | Construction | 2005 |
| Apex International Recruitment Limited | Administrative & support | 2000 |
| Apex Partners Group Ltd | Financial services | 2022 |
| Apex Partners Recruitment Ltd | Other services | 2023 |
| Applepips Ltd | Wholesale & retail | 2018 |
| Aqua Aeration Systems Ltd | Manufacturing | 2022 |
| Aqua Aims LEE Chapel LLP | | 2022 |
| Aqua Aims Limited | Education | 2016 |
| Aqua Aims Rayleigh Limited | Education | 2025 |