| AJA Steelworks Ltd | Construction | 2021 |
| AJC Trading Limited | Professional & scientific | 2013 |
| AJG Wealth Management Limited | Financial services | 2012 |
| AJI Fencing Ltd | Administrative & support | 2011 |
| AJM Property & Storage Ltd | Real estate | 2021 |
| AJO Installations Ltd | Administrative & support | 2011 |
| AJP Building & Construction Ltd | Construction | 2026 |
| AJP Business Management Limited | Professional & scientific | 2026 |
| AJS French Polishing Limited | Construction | 2014 |
| AK Commissioning Services Ltd | Professional & scientific | 2026 |
| AK Financial Consultancy Services Limited | Financial services | 2023 |
| AKD & SON Limited | Manufacturing | 2015 |
| Akidar Properties Limited | Real estate | 2024 |
| Akintempa Properties Limited | Real estate | 2024 |
| Akram's Pink Garlic Ltd | Hospitality | 2026 |
| AKS Designs Limited | Construction | 2008 |
| Akshith Consultancy Services Limited | Administrative & support | 2008 |
| Aksu Kebab Limited | Hospitality | 2018 |
| Aksum Lets Ltd | Real estate | 2020 |
| Aksum Property Ltd | Real estate | 2019 |
| AL Wafi Electromechanical Works (UK) Ltd | Manufacturing | 2019 |
| Al's PIE & Mash Ltd | Hospitality | 2014 |
| Alan Weeden Ltd | Other services | 2012 |
| Alan Wiseman Adhesives Limited | Real estate | 1974 |
| Alanpro Spares Limited | Wholesale & retail | 2024 |
| Albany Surveyors Limited | Professional & scientific | 2016 |
| Albatrans London (UK) Ltd | Transport & logistics | 2012 |
| Albert Howard Limited | Information & communication | 2014 |
| Albert James Interiors Limited | Construction | 2013 |
| Alchemy Systems Training Limited | Information & communication | 2010 |
| Alcn Consulting Ltd | Professional & scientific | 2026 |
| Alder Lodge Limited | Households | 2022 |
| Aldersbrook Residents Association Ltd | Households | 2004 |
| Aldinga Ltd | Households | 2019 |
| Aldor Care Limited | Health & social care | 2019 |
| Alea Properties Limited | Real estate | 2019 |
| Aleph Properties Limited | Real estate | 2020 |
| Alerim Research Professionals Limited | Health & social care | 2016 |
| Alex D Karidis Limited | Health & social care | 1997 |
| Alexander Fraser & SON Trading Limited | Wholesale & retail | 2014 |
| Alexander Fraser & Son,Limited | Financial services | 1908 |
| Alexander Head Media Ltd | Information & communication | 2021 |
| Alexandra Motors Limited | Wholesale & retail | 2019 |
| Alfi Car Wash Ltd | Administrative & support | 2024 |
| Algal Works Limited | Professional & scientific | 2017 |
| Alhs Projects Limited | Professional & scientific | 2024 |
| Alinter Group Limited | Extraterritorial | 2007 |
| Alinter Limited | Manufacturing | 1977 |
| Alkalife Water Limited | Water & waste | 2021 |
| ALL Educate Ltd | Education | 2016 |
| ALL England Diamond Drilling Ltd | Construction | 2009 |
| ALL England Fire Doors Ltd | Construction | 2022 |
| ALL England Group Ltd | Construction | 2014 |
| ALL England Holdings Ltd | Other services | 2017 |
| ALL Prop Limited | Real estate | 2002 |
| ALL Stars Events and Promotions Ltd | Arts & recreation | 2014 |
| ALL Storage Limited | Transport & logistics | 2024 |
| ALL3C Construction Limited | Construction | 2019 |
| Allaville Limited | Administrative & support | 2022 |
| Allba Property Ltd | Real estate | 2023 |
| Allbuilding Building Services (Essex) Ltd | Construction | 2014 |
| Allegro Health and Fitness Ltd | Arts & recreation | 2016 |
| Allfields Contractors Ltd | Construction | 2013 |
| Allied IT Solutions Ltd | Professional & scientific | 2018 |
| Allingtons Plastering Ltd | Construction | 2018 |
| Allium Park Management Company Limited | Households | 2022 |
| Allondonwomen Limited | Wholesale & retail | 2024 |
| Allouison Investments Limited | Construction | 2021 |
| Allserve London Ltd | Construction | 2022 |
| ALM Contracts Essex Ltd | Construction | 2012 |
| Alma Estate (Enfield) Management Company Limited | Households | 2017 |
| Almaureen Limited | Other services | 2019 |
| Almet London Ltd | Wholesale & retail | 2026 |
| Alml Travels and Tours Limited | Administrative & support | 2023 |
| Alpha Connectivity Ltd | Information & communication | 2020 |
| Alpha Conservation Limited | Construction | 2021 |
| Alpha Homes Limited | Real estate | 2008 |
| Alpha Medical Limited | Administrative & support | 2000 |
| Alpha Pumping Solutions Limited | Construction | 2020 |
| Alpha Vesta CIC | Administrative & support | 2019 |
| ALR Aesthetics Ltd | Health & social care | 2017 |
| ALS Casa Ltd | Wholesale & retail | 2025 |
| ALS Medical Limited | Real estate | 2022 |
| ALS Tree Surgery Limited | Administrative & support | 2012 |
| Alsewan Associates Limited | Health & social care | 2014 |
| Alsyed and Sons Trading Ltd | Wholesale & retail | 2018 |
| ALT Advisory Ltd | Professional & scientific | 2025 |
| Altex Glazing Systems Limited | Manufacturing | 1999 |
| Alvent UK Limited | Manufacturing | 2013 |
| AM Haulage Ltd | Transport & logistics | 2025 |
| Amanda Templar Design Ltd | Professional & scientific | 2021 |
| Amara Rental Management Ltd | Real estate | 2021 |
| Amathus Holidays Ltd | Administrative & support | 2023 |
| Amazing Dalters Limited | Real estate | 2022 |
| Amazing Events Limited | Arts & recreation | 2025 |
| Amber Insulations Ltd | Construction | 2014 |
| Amdark Limited | Administrative & support | 2014 |
| American Recovery European Services Ltd | Administrative & support | 2023 |
| American Video Equipment (UK) Limited | Extraterritorial | 1992 |
| Amescross Ltd | Construction | 2016 |