| AI Baba Technology UK Limited | Information & communication | 2024 |
| AI Natural Ltd | Professional & scientific | 2022 |
| AI Technova UK Limited | Information & communication | 2024 |
| AI Travel Services Ltd | Information & communication | 2025 |
| AI Your Way Ltd | Information & communication | 2025 |
| Aiaiai Ltd | Information & communication | 2025 |
| Aiborg Ltd | Professional & scientific | 2025 |
| Aide Sans Frontieres Ltd | Real estate | 2007 |
| Aidens Mould Removal Ltd | Administrative & support | 2023 |
| Aidjes Building & Refurbishment Specialist Ltd | Administrative & support | 2018 |
| Aidli Consulting Services Limited | Administrative & support | 2026 |
| Aidy Removals Ltd | Transport & logistics | 2023 |
| Aigg Holdings Ltd | Financial services | 2014 |
| Aijia Property Limited | Real estate | 2023 |
| Aikaz Limited | Health & social care | 2012 |
| AIL Accident Repair Ltd | Wholesale & retail | 2025 |
| AIL Investment Group Ltd | Real estate | 2019 |
| AIM Real Estate Investments Limited | Real estate | 2014 |
| AIM Restaurants Limited | Hospitality | 2014 |
| Aimers Academy Limited | Education | 2022 |
| Aimz UK Limited | Real estate | 2009 |
| Ainon Health Ltd | Health & social care | 2022 |
| Air Management Solutions Group Limited | Other services | 2023 |
| Air Ventures & Resources Ltd | Real estate | 2021 |
| Airisq Limited | Professional & scientific | 2001 |
| Airrea Ltd | Wholesale & retail | 2022 |
| Aiwu Builder Ltd | Construction | 2024 |
| AJ 19 Limited | Hospitality | 2019 |
| AJ Flooring Consultancy Limited | Construction | 2010 |
| AJ Scaffolding Services Ltd | Construction | 2017 |
| Ajas M&E Ltd | Construction | 2026 |
| Ajax Flooring Company Limited | Construction | 1956 |
| AJB Global Ltd | Other services | 2013 |
| AJG Office Services Limited | Professional & scientific | 2012 |
| AJL Construction Services Ltd | Construction | 2019 |
| AJM Brickwork & Construction Limited | Construction | 2025 |
| AJM Plumbing Heating & Electricals Limited | Construction | 2015 |
| AJM Retail Ltd | Wholesale & retail | 2021 |
| AJN Builders Limited | Construction | 2009 |
| Ajoke Care Limited | Health & social care | 2023 |
| Ajoks&Adufs Limited | Health & social care | 2025 |
| Ajpj Enterprises Ltd | Arts & recreation | 2026 |
| AJR Professional Services Ltd | Other services | 2015 |
| AJS Bingo Catering Ltd T/A Ajsukltd Limited | Hospitality | 2023 |
| AJS Commercial Consultants Ltd | Other services | 2015 |
| AJS Construction Limited | Construction | 2016 |
| AJS Legal Services Ltd | Professional & scientific | 2026 |
| AJU (UK) Limited | Education | 2010 |
| AJX Security Solutions Ltd | Real estate | 2019 |
| Akaaz Limited | Health & social care | 2019 |
| AKD & SON Holdings Ltd | Manufacturing | 2020 |
| Akdeniz Acquisitions Ltd | Real estate | 2025 |
| Akdeniz Developments Ltd | Construction | 2022 |
| Akerele Ventures Ltd | Transport & logistics | 2014 |
| AKG Clearance & Transport Services Ltd | Water & waste | 2025 |
| Akim's Care Limited | Health & social care | 2018 |
| Akim's Coffee Limited | Manufacturing | 2018 |
| Akim's Pet Food Trading AS Husse Greenwich Limited | Wholesale & retail | 2020 |
| Akingate Limited | Wholesale & retail | 2023 |
| Akinli Ltd | Real estate | 2024 |
| Akinyemi Studios Ltd | Information & communication | 2022 |
| Akio Financial Planning Limited | Financial services | 2026 |
| Akka Professional Services Ltd | Real estate | 2020 |
| AKP Asset Management Ltd | Real estate | 2023 |
| AKP Enterprises Ltd | Wholesale & retail | 2015 |
| AKS Finance Limited | Professional & scientific | 2010 |
| AKS Property Invest Ltd | Real estate | 2024 |
| AKS28 Ltd | Financial services | 2011 |
| Akservices Group Limited | Administrative & support | 2020 |
| Akses Global Limited | Professional & scientific | 2020 |
| Akshar IT Solutions Limited | Information & communication | 2011 |
| Akshaya Estates Ltd | Real estate | 2026 |
| Akshaya Infopoint Ltd | Information & communication | 2019 |
| Akshi Properties Ltd | Real estate | 2020 |
| Akua-Davidson Property Partners Ltd | Other services | 2023 |
| Akwascare Ltd | Public administration | 2019 |
| Akzor Limited | Hospitality | 2018 |
| AL Property Develop Ltd | Real estate | 2022 |
| AL Quadrifoglio Ltd | Hospitality | 2025 |
| AL Quraishi Limited | Real estate | 2022 |
| AL Saud & BAC Tourism Group Ltd | Administrative & support | 2025 |
| AL Usul Capital Ltd | Real estate | 2020 |
| Al-Alcon Limited | Professional & scientific | 2015 |
| Al-Haaj Bundoo Khan Ltd | Manufacturing | 2025 |
| Alacrity Business Solutions Limited | Information & communication | 2015 |
| Alade Consulting Ltd | Information & communication | 2026 |
| Alan Cousins Roofing Ltd | Construction | 2024 |
| Alberon Dolls Limited | Wholesale & retail | 1999 |
| Alberry Consulting Limited | Information & communication | 2012 |
| Albes Construction Limited | Construction | 2021 |
| Albes Group Ltd | Construction | 2026 |
| Albion Bakery Limited | Hospitality | 2015 |
| ALC Deposits Ltd | Financial services | 2025 |
| Alcantara Limited | Real estate | 2025 |
| Alchemy Software Ltd | Information & communication | 2011 |
| Alcin Estates Ltd | Real estate | 2020 |
| Aldee Innovations Ltd | Information & communication | 2012 |
| Alephed Ltd | Wholesale & retail | 2021 |
| Alex END Elena Barber Limited | Other services | 2025 |
| Alexa Developments Ltd | Construction | 2004 |