| Aalandapps Ltd | Professional & scientific | 2025 |
| Aamevol Supported Living Limited | Hospitality | 2019 |
| Aarav and Aarna PVT Ltd | Health & social care | 2025 |
| Aardent Group Holdings Ltd | Financial services | 2021 |
| Aardent Ltd | Information & communication | 2018 |
| Aarna Trades Limited | Wholesale & retail | 2013 |
| Aaron & Co Property Holdings Ltd | Real estate | 2020 |
| Aaron & Co Property Services Limited | Real estate | 2019 |
| Aaron Electrical Services Ltd | Construction | 2014 |
| Aarudra Trading Company Limited | Wholesale & retail | 2018 |
| Aarvee Property Ltd | Real estate | 2024 |
| Aarya Nails and Beauty Limited | Other services | 2013 |
| Aasa Music Ltd | Arts & recreation | 2025 |
| Aask Estates LLP | | 2021 |
| Aask Financial Ltd | Professional & scientific | 2019 |
| Aask Property Ltd | Real estate | 2025 |
| Aaxal Limited | Professional & scientific | 2007 |
| AB Accounting Services Ltd | Professional & scientific | 2004 |
| AB Autism Support & Empowerment CIC | Wholesale & retail | 2018 |
| AB Drinks Worldwide Limited | Wholesale & retail | 2019 |
| AB Legacy Limited | Real estate | 2024 |
| AB25 Investments Ltd | Real estate | 2016 |
| Abbas Car Sales Limited | Wholesale & retail | 2018 |
| Abbas Oncall Ltd | Education | 2025 |
| Abbas Properties Limited | Real estate | 2024 |
| Abbey Machinery Safety Ltd | Professional & scientific | 2019 |
| Abbey Precision Limited | Manufacturing | 1985 |
| Abbey Preservation Co. Limited | Construction | 1972 |
| Abbeycraft Consulting Limited | Professional & scientific | 2014 |
| Abbeydale Wellness Limited | Real estate | 2026 |
| Abbeyflex Limited | Information & communication | 2024 |
| Abbie Aquatics Ltd | Education | 2025 |
| Abbigayle Aesthetics Ltd | Other services | 2021 |
| Abbots Building and Refurbishments UK Limited | Construction | 2009 |
| Abbott Asset Limited | Real estate | 2025 |
| Abbott Close Management Company Limited | Real estate | 1998 |
| Abbott Funerals Limited | Extraterritorial | 2003 |
| Abbott Property Management Limited | Real estate | 1979 |
| ABC Mgmt Limited | Real estate | 2023 |
| Abcv Ltd | Real estate | 2023 |
| Abeautious Limited | Wholesale & retail | 2020 |
| Abel Kungu International Limited | Other services | 2015 |
| Abelview Homes Limited | Administrative & support | 2025 |
| Abhn Ltd | Real estate | 2015 |
| Abigail Howson Limited | Professional & scientific | 2018 |
| Abigail Miller Consulting Ltd | Professional & scientific | 2019 |
| Abigrain Ltd | Transport & logistics | 2012 |
| Abimbola Limited | Health & social care | 2023 |
| Abington Investments Limited | Real estate | 2018 |
| Abiola Studios Ltd | Information & communication | 2025 |
| Abitom Ventures Ltd | Real estate | 2022 |
| Abkm Holdings Limited | Financial services | 2020 |
| ABL Circuits Limited | Information & communication | 2001 |
| Abmcare Ltd | Health & social care | 2014 |
| About Time Ltd | Administrative & support | 2014 |
| Above View Ltd | Other services | 2015 |
| ABR Security Ltd | Administrative & support | 2018 |
| Abram Automotive Ltd | Wholesale & retail | 2025 |
| Abra’S Barbershop Ltd | Other services | 2025 |
| ABS Entertainment Ltd | Arts & recreation | 2021 |
| ABS Haulage Ltd | Transport & logistics | 2016 |
| Absolute Building and Landscape Services Limited | Administrative & support | 2022 |
| Absolute Estate Agents Limited | Real estate | 2006 |
| Absolute Installations Ltd | Construction | 2024 |
| Absolute Landscapes Limited | Administrative & support | 2015 |
| Absolute Resource Partners Ltd | Information & communication | 2019 |
| Abss Haulage Ltd | Transport & logistics | 2014 |
| Abss Skips Limited | Water & waste | 2013 |
| Abss Waste Management Limited | Water & waste | 2017 |
| Abstract Videos Ltd | Information & communication | 2024 |
| Abto Estate and Property Ltd | Real estate | 2025 |
| ABU and Rafeh Ltd | Real estate | 2025 |
| Abumusaa Ltd | Information & communication | 2024 |
| Abyt Group Ltd | Professional & scientific | 2026 |
| AC Build Limited | Construction | 2013 |
| AC Car Services Ltd | Wholesale & retail | 2008 |
| AC Carpentry and Property Maintenance Limited | Construction | 2013 |
| AC Engineering Solutions Ltd | Professional & scientific | 2019 |
| AC Tree and Landscape Ltd | Administrative & support | 2026 |
| AC3DECIMA Limited | Transport & logistics | 2024 |
| Acacia Consultants Ltd | Information & communication | 2026 |
| Academic Venue Solutions Limited | Administrative & support | 1982 |
| Academy Ballers Limited | Education | 2026 |
| Acas Constructing Ltd | Construction | 2009 |
| Acas Holdings Limited | Financial services | 2023 |
| Acav Ltd | Professional & scientific | 2024 |
| ACB Stunts Limited | Other services | 2020 |
| Accele Limited | Information & communication | 2019 |
| Accelerate Scaling Ltd | Professional & scientific | 2026 |
| Access Business Finance Ltd | Financial services | 2021 |
| Access Control for Education Ltd | Construction | 2023 |
| ACCESS93 Limited | Arts & recreation | 2024 |
| Accm(Uk) | Health & social care | 2008 |
| Accontax Ltd | Professional & scientific | 2023 |
| Accordia Training Partnership Limited | Education | 2014 |
| Accountant Advisory Services Ltd | Professional & scientific | 2020 |
| Accountologist Ltd | Professional & scientific | 2025 |
| Accovis Accounting Services Ltd | Professional & scientific | 2024 |
| Accredibase Limited | Information & communication | 2010 |
| Accurate ACC Ltd | Professional & scientific | 2012 |