| Aigain Ltd | Information & communication | 2023 |
| Aign Egerton Ltd | Real estate | 2023 |
| Aign Milton Ltd | Real estate | 2023 |
| Ailsa 3 Properties Limited | Real estate | 2013 |
| AIM Direct Creative Services Limited | Professional & scientific | 2007 |
| Ainsworth Fitzgerald Limited | Extraterritorial | 2026 |
| Aipc Holdings Ltd | Wholesale & retail | 2023 |
| Air & Sea Rescue Limited | Extraterritorial | 2021 |
| Air Conditioning Accessories (North West) Limited | Wholesale & retail | 2006 |
| Air Conditioning Accessories Limited | Wholesale & retail | 2004 |
| Air Conditioning Services (UK) Limited | Construction | 2013 |
| Aireside Accounting and Consultancy Ltd | Professional & scientific | 2022 |
| Airhgt Ltd | Hospitality | 2023 |
| Airpac Rentals Holdco Limited | Administrative & support | 2023 |
| Airpac Rentals UK Limited | Administrative & support | 2023 |
| Airport West (Leeds) Limited | Real estate | 2003 |
| Airport West Management Company Limited | Real estate | 2005 |
| Airquoter Limited | Extraterritorial | 2024 |
| Airwater Technology Limited | Water & waste | 2024 |
| Aiskew Farm Estate LLP | | 2026 |
| Aissistant Ltd | Information & communication | 2025 |
| Aitchco Ltd | Professional & scientific | 2018 |
| Aitkin Limited | Extraterritorial | 2024 |
| AJ Acquisitions Limited | Real estate | 2025 |
| AJ Dickinson Consulting Ltd | Professional & scientific | 2026 |
| Ajay Handa Consulting Limited | Professional & scientific | 2018 |
| AJB Financial Solutions Limited | Financial services | 2017 |
| AJB IT Consulting Ltd | Information & communication | 2025 |
| Ajeb Healthcare Ltd | Health & social care | 2024 |
| AJF Executive Search Limited | Administrative & support | 2007 |
| AJF International Search Ltd | Administrative & support | 2011 |
| AJS 22 Ltd | Real estate | 1988 |
| AJS Haulage Limited | Transport & logistics | 2016 |
| AK Turner Limited | Professional & scientific | 2003 |
| Akdixon Properties Ltd | Real estate | 2019 |
| Aketon Limited | Financial services | 2003 |
| Aksyum Limited | Information & communication | 2018 |
| Aktiv (Harrogate) Ltd | Construction | 2025 |
| Aktiv Design (Marble and Granite) Limited | Manufacturing | 2003 |
| Aktiv Properties Limited | Real estate | 2021 |
| Akula Holdings Limited | Financial services | 2023 |
| AKW Investment Limited | Professional & scientific | 2013 |
| AL Abaq Perfumes Ltd | Wholesale & retail | 2024 |
| AL Bassam International Ltd | Construction | 2021 |
| AL Bivio (Hornbeam Park) Limited | Hospitality | 2004 |
| AL Mears and SON Ltd | Administrative & support | 2015 |
| AL Safa Garments Trading Ltd | Manufacturing | 2025 |
| AL Yusr AL Inshaiyah Ltd | Wholesale & retail | 2024 |
| Al-Hilali Contracting and Real Estate Development Company Limited | Manufacturing | 2024 |
| Al-Hodhod for Trading Ltd | Wholesale & retail | 2024 |
| Al-Nilain Comprehensive Services Ltd | Extraterritorial | 2021 |
| Al-Soura Bel-Sadara Media Production Company Ltd | Professional & scientific | 2022 |
| AL1SON Limited | Extraterritorial | 2020 |
| AL3X Ltd | Extraterritorial | 2016 |
| Alafaq Global Trading Ltd | Construction | 2025 |
| Alam Decoration and Gypsum Board Material Trading Ltd | Wholesale & retail | 2025 |
| Alan Peel Decorators Limited | Construction | 2003 |
| Alara for Trade Ltd | Wholesale & retail | 2022 |
| Alasdair Ltd | Wholesale & retail | 2021 |
| Alastair Mackie Ltd | Professional & scientific | 2017 |
| Albandar Ltd | Construction | 2024 |
| Albany House (Harrogate) Limited | Real estate | 2007 |
| Albany House (HMD) Management Ltd | Households | 2003 |
| Albarosa Limited | Real estate | 2019 |
| Albashiri Contracting and Trading Ltd | Construction | 2024 |
| Albert Alessi Limited | Extraterritorial | 2025 |
| Albert Arthur Properties Ltd | Real estate | 2021 |
| Albert Hymas Limited | Real estate | 1957 |
| Albino Dias DE Andrade Ltd | Manufacturing | 2021 |
| ALC Home Solutions Limited | Construction | 2025 |
| Alchemist Consulting Group Ltd | Professional & scientific | 2019 |
| Alchemy Media Limited | Professional & scientific | 2006 |
| Alchemy Microcement Limited | Construction | 2024 |
| Alchemy Surfaces Limited | Construction | 2025 |
| Alchymies Limited | Real estate | 2020 |
| Alderi Company Ltd | Wholesale & retail | 2024 |
| Alderson House Limited | Households | 1999 |
| Alderson Investco Limited | Extraterritorial | 2021 |
| Alderson Investco Properties Limited | Real estate | 2021 |
| Alderson Tax Limited | Professional & scientific | 2017 |
| Aldino's Pizza Ltd | Hospitality | 2024 |
| Aldous Emea Ltd | Professional & scientific | 2018 |
| Alere Pharma Consulting Limited | Other services | 2021 |
| Aleu Ltd | Wholesale & retail | 2010 |
| Alex Long Ltd | Transport & logistics | 2025 |
| Alexa Ryan-Mills Garden Design Ltd | Professional & scientific | 2015 |
| Alexander Rose International Limited | Administrative & support | 2020 |
| Alexander Sedgbeer Ltd | Education | 2022 |
| Alexander Wedding & Events Ltd | Hospitality | 2019 |
| Alexandra Hub Ltd | Real estate | 2022 |
| Alf's Cornershop Ltd | Administrative & support | 2021 |
| ALF1E Limited | Extraterritorial | 2018 |
| Alfa Interntional Ltd | Wholesale & retail | 2021 |
| Alfahd Trading Ltd | Construction | 2022 |
| Alfajr Sunrise Ltd | Agriculture & fishing | 2021 |
| Alfasync Ltd | Health & social care | 2023 |
| Alfora Ltd | Professional & scientific | 2025 |
| Alfred Francis Limited | Administrative & support | 2017 |
| ALG Builders Limited | Construction | 2016 |
| ALG Property Ltd | Hospitality | 2025 |