| Anderson Fibre Solutions Ltd | Information & communication | 2022 |
| Anderson Projects Ltd | Information & communication | 2010 |
| Andrew Clay Haulage Limited | Transport & logistics | 2019 |
| Andrew TAW Ltd. | Information & communication | 2013 |
| Andrew Telling Limited | Information & communication | 2013 |
| Andtrace Ltd | Wholesale & retail | 2012 |
| Andy`S Baits Ltd | Agriculture & fishing | 2008 |
| Angel Risk Management Software Ltd | Information & communication | 2020 |
| Angels & Dragons Ltd | Information & communication | 2025 |
| Angem Limited | Wholesale & retail | 2020 |
| Anglepoise Holdings Limited | Manufacturing | 1975 |
| Anglepoise Limited | Manufacturing | 2004 |
| Anglo Accountancy & Tax Services Limited | Professional & scientific | 1999 |
| Anglo Accountancy Limited | Professional & scientific | 2004 |
| Anglopainting.Co.Uk Limited | Construction | 2024 |
| Animal Star Awards Limited | Administrative & support | 2026 |
| Animal Star Events Ltd | Administrative & support | 2022 |
| ANJ Holdings Ltd | Professional & scientific | 2019 |
| Anka Metal Coatings (Holdings) Limited | Financial services | 2015 |
| Anmore Dressage Limited | Agriculture & fishing | 2025 |
| Anmore Limited | Agriculture & fishing | 2023 |
| ANN Dalby Associates Limited | Health & social care | 2008 |
| Annette Clark Consultancy Ltd | Professional & scientific | 2023 |
| Annexe Records Ltd | Information & communication | 2021 |
| Anor & ASH Co Ltd | Real estate | 2024 |
| Another Level Building Services Ltd | Construction | 2017 |
| Antarctic Systems Limited | Information & communication | 2024 |
| Antares Marine Ltd | Construction | 2024 |
| Antares Property Services Limited | Construction | 2017 |
| Antech Engineered Solutions Limited | Manufacturing | 2014 |
| Antech Projects Limited | Real estate | 2017 |
| Anteroom Art Projects Limited | Education | 2024 |
| Anthill Investments Limited | Real estate | 2012 |
| Anthony & Sons Limited | Construction | 2002 |
| Antivisiion Ltd | Information & communication | 2026 |
| Antz Electrical Ltd | Construction | 2017 |
| Anubias Ltd | Construction | 2024 |
| Anuke Limited Liability Partnership | | 2020 |
| ANY Property Investors Limited | Real estate | 2024 |
| Anytime Rail & Property Services Limited | Construction | 2016 |
| Anywhere WE Roam Ltd | Information & communication | 2023 |
| AO Plastering Limited | Construction | 2020 |
| AP Global Investments Limited | Real estate | 2023 |
| Apex Commercial Perspectives Ltd | Construction | 2025 |
| Apex Electrical Controls Ltd | Construction | 2018 |
| Apex Global Security Solutions Ltd | Administrative & support | 2024 |
| Apex Industrial Roofing & Cladding Limited | Construction | 2016 |
| Apex Mortgage Brokers Ltd | Financial services | 2025 |
| Apex Padle Ball Ltd | Arts & recreation | 2025 |
| Apex Roofing & Claddding Ltd Ltd | Construction | 2026 |
| Apex South FC CIC | Arts & recreation | 2026 |
| Apex Strategic Consultants Limited | Financial services | 2025 |
| Apex Team Ltd | Professional & scientific | 2010 |
| Apex Vehicle Sales and Service Limited | Wholesale & retail | 2024 |
| Apexmint UK Ltd | Wholesale & retail | 2025 |
| Aphrodite Plumbing & Heating Ltd | Construction | 2022 |
| Aphrodite Solutions Ltd | Administrative & support | 2016 |
| Apical Roofing and Leadworks Ltd | Construction | 2014 |
| APK Optics Limited | Other services | 2022 |
| Apogee Group Recruitment Limited | Professional & scientific | 2006 |
| Apollo Dionysus Music Group Ltd | Arts & recreation | 2023 |
| Appealing HR Ltd | Professional & scientific | 2010 |
| Appelboam Ltd | Professional & scientific | 2024 |
| Appian Way Ltd | Construction | 2023 |
| Apple Park Films Ltd | Information & communication | 2013 |
| Apple Tree Property Services Ltd | Construction | 2024 |
| Applebee Developments Ltd | Construction | 2023 |
| Applewood Bespoke Developments Ltd | Construction | 2015 |
| Applied Countermark Technology Limited | Professional & scientific | 2011 |
| Appnow Limited | Information & communication | 2025 |
| Apprenticeships Directory Limited | Education | 2019 |
| Appy Apple Limited | Construction | 2026 |
| APR Powder Coatings Limited | Administrative & support | 2007 |
| APT Building Projects Ltd | Construction | 2024 |
| Aptanet Limited | Information & communication | 2003 |
| Aptis Consulting Limited | Professional & scientific | 2019 |
| AQ Fire Solutions Ltd | Professional & scientific | 2025 |
| Aqua Pure Window Wizards Limited | Administrative & support | 2014 |
| Aquaiot Ltd | Professional & scientific | 2025 |
| Aquaplasma Ltd | Manufacturing | 2026 |
| Aquatherm Plumbing & Heating Limited | Construction | 2003 |
| Aquila Architecture Limited | Professional & scientific | 2022 |
| Aquilan MED UK Limited | Health & social care | 2025 |
| Aranstone Investments Limited | Professional & scientific | 2020 |
| Arbia Limited | Professional & scientific | 2018 |
| Arboo Ltd | Information & communication | 2025 |
| Arbor Service Group Ltd | Wholesale & retail | 2024 |
| Arbro Tree Surgeons Limited | Administrative & support | 2002 |
| ARC Direct Ltd | Wholesale & retail | 2024 |
| ARC Healthcare Ltd | Health & social care | 2019 |
| ARC Planning Ltd | Construction | 2024 |
| ARC Software Ltd | Information & communication | 2024 |
| Arcade Fire & Security Limited | Construction | 2011 |
| Archbold & Edwards Ltd | Real estate | 2016 |
| Archibald Build Limited | Construction | 2022 |
| Archos Search Limited | Administrative & support | 2023 |
| Arden Fives Ltd | Administrative & support | 2022 |
| Ardito Claims Validation Surveyors Limited | Construction | 2012 |
| Arelem Roofing Limited | Construction | 2022 |
| Arena Recoveries Limited | Administrative & support | 2021 |