| Aaan Medical Ltd | Health & social care | 2024 |
| AAC Capital Ltd | Real estate | 2017 |
| Aadhya Accountants Limited | Professional & scientific | 2020 |
| Aads Property Management Ltd | Real estate | 2015 |
| Aadya Consulting Services Limited | Information & communication | 2019 |
| Aaiivaa Limited | Construction | 2016 |
| AAM247 Rides Limited | Transport & logistics | 2025 |
| Aamara Ltd | Wholesale & retail | 2026 |
| AAN Tyagi Properties Limited | Real estate | 2023 |
| Aanja Management Services Ltd | Professional & scientific | 2020 |
| Aaran Darr and Co Limited | Construction | 2007 |
| Aaranya Properties Ltd | Real estate | 2022 |
| Aarav Infotech Limited | Information & communication | 2013 |
| Aarc Capital Limited | Financial services | 2016 |
| Aardee Investment Holdings Limited | Administrative & support | 2015 |
| Aardee Real Estate Enterprises Limited | Financial services | 2018 |
| Aarkev Ltd | Wholesale & retail | 2023 |
| Aarna Enterprise Limited | Hospitality | 2011 |
| Aarnic Bridging Comparison Ltd | Financial services | 2021 |
| Aarnic Ltd | Professional & scientific | 2015 |
| Aarnic Properties Ltd | Real estate | 2022 |
| Aaronair Services Ltd | Transport & logistics | 2020 |
| Aarti Optics Ltd | Health & social care | 2025 |
| Aarvigil Life Sciences Limited | Professional & scientific | 2024 |
| Aarya Hospitality Ltd | Hospitality | 2026 |
| Aaryohi Limited | Real estate | 2022 |
| AAS Imports Ltd | Wholesale & retail | 2023 |
| AAS Service Ltd | Health & social care | 2026 |
| Aasha Limited | Professional & scientific | 2012 |
| Aashiyana Estates Limited | Real estate | 2026 |
| Aastha Ltd | Information & communication | 2014 |
| AAT (GB) Limited | Wholesale & retail | 2004 |
| AAT Consulting Limited | Other services | 2010 |
| Aate Limited | Professional & scientific | 2016 |
| Aavaas Capital Ltd | Real estate | 2020 |
| Aavyah Limited | Wholesale & retail | 2025 |
| Aayu-Boho Ltd | Wholesale & retail | 2023 |
| Aayusi Ltd | Real estate | 2024 |
| AB Designs and Structures UK P Ltd | Construction | 2019 |
| AB Lighting Limited | Construction | 2011 |
| AB OTB Electrician Ltd | Construction | 2022 |
| AB Solutions Construction Ltd | Construction | 2022 |
| AB Solutions Electrical Limited | Construction | 2014 |
| AB Tax Services Ltd | Professional & scientific | 2018 |
| AB Wahrung Limited | Wholesale & retail | 2024 |
| AB34 Holdings Ltd | Financial services | 2025 |
| AB34 Investments Ltd | Real estate | 2021 |
| Abacus Infotech Limited | Information & communication | 2013 |
| Abacus Management and Training Consultancy Limited | Professional & scientific | 2007 |
| Abati Publishing Limited | Wholesale & retail | 2025 |
| Abay Investments Company Limited | Real estate | 2019 |
| ABB Safety Solutions Ltd | Professional & scientific | 2016 |
| Abbas Auto Tech Ltd | Wholesale & retail | 2019 |
| Abbay Dale Ltd | Transport & logistics | 2026 |
| Abbey Green Cars Ltd | Transport & logistics | 2022 |
| Abbey Property Agents Ltd | Real estate | 2015 |
| Abbeyleecare Ltd | Health & social care | 2022 |
| Abbeymore Consultancy Limited | Information & communication | 1994 |
| Abbots Professional Services Limited | Administrative & support | 2023 |
| Abbots Willow Group Limited | Administrative & support | 2026 |
| Abbots Windows Ltd | Construction | 2012 |
| Abbrevi LP | | 2017 |
| Abby Projects Limited | Financial services | 2015 |
| Abby Waste Services Limited | Water & waste | 2016 |
| ABC Coaching Limited | Education | 2018 |
| ABC Hillingdon Ltd | Health & social care | 2012 |
| ABC Lifts Ltd | Manufacturing | 2024 |
| ABC One Properties Ltd | Real estate | 2025 |
| ABC Oral Healthcare Ltd | Health & social care | 2011 |
| ABC Property Group Ltd | Construction | 2021 |
| ABC Refrigeration Ltd | Manufacturing | 2019 |
| ABC UK Trading Ltd | Hospitality | 2024 |
| Abcares Limited | Health & social care | 2015 |
| Abcd Lift Specialist Ltd | Manufacturing | 2021 |
| ABD Cars Limited | Wholesale & retail | 2025 |
| Abdulhamid Limited | Professional & scientific | 2023 |
| Abeke Limited | Information & communication | 2009 |
| Abencraft Limited | Manufacturing | 2019 |
| Abetta Couriers (UK) Limited | Transport & logistics | 2017 |
| Abetta Travel Services Limited | Transport & logistics | 2009 |
| Abflow Plumbing Services Ltd | Construction | 2015 |
| Abiel Consultancy Limited | Information & communication | 2014 |
| Abilities Development Transport Ltd | Transport & logistics | 2014 |
| Able-Direct Centre Limited | Manufacturing | 1973 |
| Ablecrew Limited | Administrative & support | 2006 |
| Ablegrip Investments Limited | Financial services | 2012 |
| Ablegrip Limited | Wholesale & retail | 1988 |
| ABM Motors Limited | Wholesale & retail | 1994 |
| ABN Cleaning Services Limited | Administrative & support | 2007 |
| ABN Finance Ltd | Financial services | 2023 |
| Abrg Properties Ltd | Real estate | 2021 |
| Abries Ltd | Professional & scientific | 2012 |
| ABS Consultancy Limited | Information & communication | 2006 |
| Abshire Consulting Limited | Information & communication | 2010 |
| Absolute Ceramics Limited | Wholesale & retail | 2006 |
| Absolute Clinical Consultancy Limited | Health & social care | 2022 |
| Absolute Management Services Limited | Real estate | 2017 |
| Absolute Results Sales and Marketing Ltd | Information & communication | 2016 |
| Abstract Cooling Limited | Manufacturing | 2020 |
| Abstract Windows Ltd | Administrative & support | 2023 |