| A.C Evolve Ltd | Hospitality | 2025 |
| A.C.E. Solar Green Building Services Ltd | Construction | 2016 |
| A.C.E. Solar Green Holdings Limited | Real estate | 2018 |
| A.D Electrical Solutions Limited | Construction | 2016 |
| A.D.S. Painters & Decorators Limited | Construction | 1999 |
| A.F. Treacher Glazing Limited | Construction | 1999 |
| A.L.T. Fire Stopping Limited | Construction | 2023 |
| A.M. International Limited | Professional & scientific | 1998 |
| A.M.I O Ltd | Wholesale & retail | 2025 |
| A.N.A Mentoring Ltd | Other services | 2024 |
| A.N.Y.A Consulting Limited | Professional & scientific | 2019 |
| A.P. Consulting Solutions Ltd | Professional & scientific | 2025 |
| A.R.Javed Limited | Wholesale & retail | 2016 |
| A.R.Toms Electrical Services Ltd | Construction | 2019 |
| A.S. Design & Build Ltd | Construction | 2024 |
| A.V. Force Ltd | Administrative & support | 2023 |
| A.Z.S Construction Limited | Construction | 2025 |
| A1 Brickwork Essex Ltd | Construction | 2020 |
| A1 Building and Roofing Work Ltd | Construction | 2025 |
| A1 Energies Limited | Administrative & support | 2017 |
| A1 Green Ltd | Wholesale & retail | 2023 |
| A1 London Furniture Ltd | Wholesale & retail | 2020 |
| A1 Marketing Solutions Limited | Information & communication | 2019 |
| A1 Mohar Construction UK Ltd | Construction | 2015 |
| A1 Wholesale Distribution Ltd | Wholesale & retail | 2020 |
| A12 Cafe Ltd | Hospitality | 2016 |
| A12 Car Wash Ltd | Administrative & support | 2023 |
| A13 Steel Scaffolding Ltd | Construction | 2016 |
| A2 Cybernetiks Ltd | Information & communication | 2024 |
| A2A Trading Limited | Wholesale & retail | 2024 |
| A2Z Dentistry Ltd | Health & social care | 2024 |
| A2Z Distributions Limited | Transport & logistics | 2018 |
| A2Z Interior Solutions Ltd | Construction | 2012 |
| A2Z Property Services Limited | Real estate | 2025 |
| A2ZHOUSES Ltd | Real estate | 2026 |
| A4 Assets Properties Limited | Real estate | 2022 |
| A4 Events Ltd | Hospitality | 2015 |
| AA & BB Ltd | Extraterritorial | 2024 |
| AA & NP Ltd | Hospitality | 2024 |
| AA & Traders UK Ltd | Wholesale & retail | 2021 |
| AA Capital Security Services Limited | Administrative & support | 2014 |
| AA Dream Subway Ltd | Hospitality | 2023 |
| AA Education Network Limited | Education | 2026 |
| AA Elite Limited | Real estate | 2024 |
| AA Global Consulting Ltd | Information & communication | 2026 |
| AA Plates Ltd | Manufacturing | 2024 |
| AA Plus Plumbing Ltd | Construction | 2019 |
| AA Quick Solution Ltd | Professional & scientific | 2023 |
| AA Residentials Ltd | Real estate | 2023 |
| AA Service UK Ltd | Other services | 2007 |
| AA Servicepro UK Ltd | Manufacturing | 2024 |
| AA UK Services Ltd | Hospitality | 2023 |
| AA1 Build Ltd | Construction | 2022 |
| AAA East Builders Limited | Construction | 2014 |
| AAA Prop Limited | Real estate | 2013 |
| AAA Traders Ltd | Wholesale & retail | 2018 |
| Aadhya PJ Ltd | Professional & scientific | 2018 |
| AAH (Trading AS Ecofocal) Limited | Wholesale & retail | 2026 |
| Aahil Motors Limited | Wholesale & retail | 2023 |
| AAK9 Security Ltd | Administrative & support | 2022 |
| Aaliahome Limited | Wholesale & retail | 2018 |
| AAM Business Consulting Limited | Professional & scientific | 2024 |
| Aamna Khokhar Limited | Other services | 2015 |
| Aaninternational Limited | Wholesale & retail | 2023 |
| Aans Properties Ltd | Real estate | 2021 |
| Aaqib Enterprise UK Limited | Wholesale & retail | 2025 |
| Aaravi Solutions Ltd | Real estate | 2018 |
| Aardwolf Services Limited | Information & communication | 2016 |
| Aarion Construction Ltd | Construction | 2024 |
| Aarmi Developments (London) Ltd | Real estate | 2020 |
| Aarmi Developments Ltd | Real estate | 2020 |
| Aaron Figgett Photography Ltd | Professional & scientific | 2023 |
| Aaron Holmes Limited | Real estate | 2014 |
| Aaron's Convenience Store Limited | Wholesale & retail | 2016 |
| Aashray Ltd | Real estate | 2022 |
| AAZ Transport Ltd | Transport & logistics | 2025 |
| Aaz-Motors Limited | Wholesale & retail | 2024 |
| AB & RB Medical Ltd | Health & social care | 2018 |
| AB Carpentry Services Ltd | Construction | 2025 |
| AB Constr Limited | Construction | 2024 |
| AB Electrical LDN Limited | Construction | 2025 |
| AB Enterprise Group Ltd | Financial services | 2023 |
| AB Investments Ltd | Financial services | 2022 |
| AB Premier Cleaning Group Limited | Administrative & support | 2020 |
| AB Property Asset Ltd | Administrative & support | 2017 |
| AB Residential Holdings Ltd | Real estate | 2025 |
| AB Studios International Ltd | Wholesale & retail | 2025 |
| AB Supplies LDN Ltd | Wholesale & retail | 2025 |
| Ab&Ba Ltd. | Transport & logistics | 2015 |
| AB11Y Software Ltd | Information & communication | 2020 |
| ABA Initiatives Ltd | Real estate | 2022 |
| Abacan Investments Ltd | Administrative & support | 2020 |
| Abacus 59 Limited | Professional & scientific | 2009 |
| Abacus Accountants and Business Advisors Limited | Extraterritorial | 2010 |
| Abacus Consultancy (GB) Limited | Information & communication | 2008 |
| Abacus Roofing Ltd | Construction | 2022 |
| Abacusonlinesolutions Limited | Professional & scientific | 2017 |
| ABAN1 Solutions Limited | Water & waste | 2025 |
| Abarak Investments Limited | Real estate | 2016 |
| Abashon Homes Limited | Real estate | 2026 |