| Apman Limited | Real estate | 2024 |
| Apocrypha Entertainment Limited | Information & communication | 2023 |
| Apollo Business Broking Limited | Other services | 2019 |
| Apollo Care Limited | Administrative & support | 2020 |
| Apollo Consultants International Limited | Information & communication | 1989 |
| Apollo Events Live Limited | Arts & recreation | 2025 |
| App Software Ltd | Information & communication | 2009 |
| Appj Group Ltd | Real estate | 2024 |
| Appjaw Ltd | Information & communication | 2026 |
| Apple Gate Support Ltd | Health & social care | 2023 |
| Appleby Consultants Ltd | Professional & scientific | 2010 |
| Appleby Woodturnings Limited | Manufacturing | 2014 |
| Applecore Arbitrage Ltd | Wholesale & retail | 2020 |
| Applecore Production Ltd | Administrative & support | 2021 |
| Appletree Housing Ltd | Real estate | 2025 |
| Appletree&Co Limited | Hospitality | 2024 |
| Applewood (Mirfield) Estate Management Company Limited | Households | 2023 |
| Appliance & Electrical Services Limited | Other services | 2009 |
| Appliance Medic (Midlands) Ltd | Other services | 2018 |
| Applied Inspection Limited | Professional & scientific | 1984 |
| Applied Martial Arts Academy Ltd | Arts & recreation | 2021 |
| Applied Performance Intelligence Ltd | Professional & scientific | 2026 |
| Approved Bathrooms Ltd | Construction | 2025 |
| Approved Building Control Ltd | Construction | 2017 |
| Approved Tiling Ltd | Construction | 2024 |
| Appsavvy Consulting Ltd | Information & communication | 2023 |
| Apptiv Limited | Information & communication | 2021 |
| APR Expert Ltd | Financial services | 2018 |
| APR Money Ltd | Financial services | 2017 |
| April Exeter Limited | Administrative & support | 2015 |
| April Exmouth Limited | Administrative & support | 2015 |
| APS Estates Management Ltd | Real estate | 2023 |
| APS Legal & Associates Limited | Professional & scientific | 2005 |
| Apsc Investments Limited | Real estate | 2024 |
| Apsion Training Services Limited | Education | 2016 |
| Apsm Limited | Other services | 2025 |
| APT Harris Developments Ltd | Real estate | 2024 |
| AQ Transport Ltd | Transport & logistics | 2013 |
| Aq&A Limited | Manufacturing | 2024 |
| Aq-Aaa Limited | Other services | 2020 |
| AQL Property Services Ltd | Real estate | 2023 |
| Aqlq Holdings Ltd | Financial services | 2026 |
| Aqsales Limited | Wholesale & retail | 2025 |
| Aqua Narrowboats (MFG) Limited | Manufacturing | 2023 |
| Aqua Rhythm Limited | Arts & recreation | 2017 |
| Aqua Surge Ltd | Water & waste | 2026 |
| Aqua-Jet Specialist Drainage Contractors Limited | Administrative & support | 2001 |
| Aquaclean Textiles Ltd | Wholesale & retail | 2020 |
| Aquae Sulis Ltd | Real estate | 2024 |
| Aquahydra Technologies Ltd | Financial services | 2021 |
| Aqualon UK Ltd | Wholesale & retail | 2023 |
| Aqualuxe Bathrooms Ltd | Wholesale & retail | 2026 |
| Aquam Water Services Limited | Administrative & support | 2015 |
| Aquathlete Ltd | Administrative & support | 2016 |
| Aqui Developments Limited | Construction | 2016 |
| Aquila Care Academy Limited | Administrative & support | 2022 |
| Aquila Therapeutic Centre Limited | Health & social care | 2017 |
| Aqxmmc Limited | Professional & scientific | 2014 |
| AR Carelink Ltd | Health & social care | 2023 |
| AR Cholerton Limited | Construction | 2001 |
| AR Clarke Consultants Limited | Health & social care | 2016 |
| AR Corporate Services (Burton) Ltd | Professional & scientific | 2020 |
| AR Corporate Services Ltd | Professional & scientific | 2018 |
| AR Fleetfix Ltd | Wholesale & retail | 2025 |
| AR Mill Street Ltd | Real estate | 2019 |
| AR Perfusion Services Ltd | Health & social care | 2023 |
| AR Pharms Limited | Health & social care | 2013 |
| AR Sandhu Ltd | Transport & logistics | 2025 |
| AR Transportation Ltd | Transport & logistics | 2014 |
| ARA Investment Enterprises Limited | Real estate | 2019 |
| ARA Management Services Limited | Professional & scientific | 2018 |
| ARA Property Development Limited | Extraterritorial | 2012 |
| ARA Rental Properties Limited | Real estate | 2002 |
| Araasa Ltd | Wholesale & retail | 2022 |
| Arabian Grill Ltd | Hospitality | 2024 |
| Arabiana Limited | Information & communication | 2018 |
| Aradhanauk Limited | Hospitality | 2026 |
| Aradyan Mini Market Limited | Wholesale & retail | 2022 |
| Aram Building Ltd | Other services | 2026 |
| Arams Barbershop Ltd | Other services | 2026 |
| Aran Hall School Limited | Education | 1991 |
| Arboreal Interactive Ltd | Information & communication | 2025 |
| Arboretum Enterprises Group Ltd | Financial services | 2019 |
| Arboretum Homes Ltd | Construction | 2015 |
| Arboretum Hotels Ltd | Hospitality | 2020 |
| Arboretum Investments Ltd | Real estate | 2018 |
| Arboretum Property Holdings Ltd | Real estate | 2019 |
| Arboretum Retreats Ltd | Real estate | 2024 |
| Arboretum Shopify Ltd | Wholesale & retail | 2025 |
| Arboretum Winding Brook Ltd | Construction | 2017 |
| ARC Digital Solutions Ltd | Information & communication | 2026 |
| ARC Drift Experience Ltd | Arts & recreation | 2026 |
| ARC Mechanical and Electrical Ltd | Manufacturing | 2011 |
| ARC Portfolio Management Limited | Professional & scientific | 2008 |
| Arcadian Marinades Ltd | Arts & recreation | 2019 |
| Arcar Consulting Limited | Real estate | 2022 |
| Arch Visual Limited | Professional & scientific | 2025 |
| Arched Holdings Limited | Financial services | 2020 |
| Arched Properties Limited | Real estate | 2024 |
| Archer Construction Group Ltd | Construction | 2024 |