| AJB Carpentry Limited | Manufacturing | 2017 |
| AJF Property Group Ltd | Real estate | 2021 |
| Ajingo Autocentre UK Ltd | Wholesale & retail | 2019 |
| Ajito Property Limited | Construction | 2025 |
| Ajito Property SW1 Limited | Real estate | 2026 |
| AJM and Associates Limited | Professional & scientific | 2009 |
| AJM Estates Limited | Real estate | 2010 |
| AJM Property Developments Ltd | Financial services | 2018 |
| AJM Rental Services Ltd | Real estate | 2026 |
| Ajrm 25 Ltd | Real estate | 2025 |
| AK Automation Holdings Limited | Financial services | 2026 |
| AKA (UK) Limitem Ltd | Wholesale & retail | 2015 |
| AKA Movement Ltd | Other services | 2026 |
| AKA Properties London Ltd | Other services | 2023 |
| Akashco Restaurant Limited | Hospitality | 2024 |
| AKM Trading Ltd | Wholesale & retail | 2020 |
| AL Daraji Real Estates Ltd | Real estate | 2020 |
| AL Shaheer Marine Services Ltd | Transport & logistics | 2018 |
| AL Specialist Mortgage Solutions Ltd | Financial services | 2023 |
| Al's Bar Ltd | Hospitality | 2021 |
| Alam FS Ltd | Financial services | 2026 |
| Alamrap Holdings Limited | Manufacturing | 2023 |
| Alan Brown Electrical Ltd | Manufacturing | 2018 |
| Alarm Testing Ltd | Professional & scientific | 2021 |
| Alasha Ltd | Wholesale & retail | 2022 |
| Albany Carpet and Upholstery Cleaning Ltd | Administrative & support | 2011 |
| Albatross Media Ltd | Professional & scientific | 2021 |
| Alben Products Limited | Wholesale & retail | 2016 |
| Albeon Steel & Wire Ltd | Wholesale & retail | 2025 |
| Albert Choi Associates Ltd | Administrative & support | 2017 |
| Albert Road Market Limited | Wholesale & retail | 2025 |
| Albert Road Promotions Ltd | Wholesale & retail | 2012 |
| ALC Design & Developments Ltd | Construction | 2022 |
| ALC Plastering Ltd | Construction | 2026 |
| Alcazar London Limited | Financial services | 2023 |
| Alcheme Ltd | Health & social care | 2018 |
| Alchemy Educational Training Ltd | Professional & scientific | 2012 |
| Alder (Management Services) Limited | Construction | 1978 |
| Alectron Ltd | Manufacturing | 2017 |
| Aleksandar Limited | Wholesale & retail | 2026 |
| Alethia Health Ltd | Professional & scientific | 2025 |
| Alex Auto Portsmouth Ltd | Wholesale & retail | 2021 |
| Alex James Homes Limited | Real estate | 2021 |
| Alex Winship Photography Ltd | Professional & scientific | 2016 |
| Alexander Autos Portsmouth Limited | Wholesale & retail | 2018 |
| Alexandra Mews Limited | Real estate | 1995 |
| Alexandra Sports Limited | Wholesale & retail | 1993 |
| Alexandru Designs Limited | Professional & scientific | 2024 |
| Alexis Gleam and Shine Ltd | Administrative & support | 2024 |
| Alexis Properties Ltd | Real estate | 2021 |
| Alfredo Consultancy Ltd | Health & social care | 2026 |
| Algusta Golf Limited | Wholesale & retail | 2026 |
| ALI JEE Limited | Real estate | 2012 |
| ALI Liaquat Financial Solutions Limited | Administrative & support | 2014 |
| Alice Mode Ltd | Wholesale & retail | 2024 |
| Align Performance Sports Ltd | Arts & recreation | 2022 |
| Aljac Holdings Limited | Professional & scientific | 1998 |
| ALL About GAS, Heating and Plumbing Services Limited | Construction | 2007 |
| ALL About Skin Studio Ltd | Other services | 2020 |
| ALL Aspects Plastering Limited | Construction | 2025 |
| ALL Four Seasons Playcafe Limited | Hospitality | 2025 |
| ALL Heart Marine UK Ltd | Wholesale & retail | 2026 |
| ALL Hours Plumbing Limited | Construction | 1996 |
| ALL in Brand Ltd | Wholesale & retail | 2022 |
| ALL Lanes Assets Ltd | Administrative & support | 2025 |
| ALL Lanes Holdings Ltd | Financial services | 2025 |
| ALL Lanes Traffic Management Ltd | Construction | 2022 |
| ALL Over Waste Management and Recycling Ltd | Water & waste | 2026 |
| ALL Parts Automotive Ltd | Wholesale & retail | 2024 |
| ALL Scope Construction Limited | Construction | 2025 |
| ALL Seasons Mechanical Ltd | Construction | 2019 |
| ALL Stars Ventures Limited | Health & social care | 2026 |
| ALL Things Canine Limited | Other services | 2022 |
| ALL Together Leisure Ltd | Arts & recreation | 2019 |
| Allanson (IOW) Limited | Other services | 2023 |
| Allaway Fish Bar Limited | Hospitality | 2025 |
| Allaway Healthcare Limited | Wholesale & retail | 2024 |
| Allcorn Engineering Limited | Professional & scientific | 2009 |
| Allcorn Smoke Control Ltd | Construction | 2023 |
| Alleron Developments Limited | Construction | 1987 |
| Allevia Care Ltd | Health & social care | 2026 |
| Allmet Duct Services Limited | Manufacturing | 2000 |
| Allo Chat Ltd | Hospitality | 2019 |
| Allsafe Solutions Ltd | Administrative & support | 2019 |
| Allsteel Solutions Limited | Construction | 2025 |
| Alltrades Recruitment Services Ltd | Administrative & support | 2020 |
| Allwood Design and Manufacture Ltd | Construction | 2008 |
| Ally Consultancy Ltd | Professional & scientific | 2021 |
| Ally Gordon Coaching Ltd | Professional & scientific | 2020 |
| ALM Estate Limited | Administrative & support | 2013 |
| Almade Limited | Administrative & support | 2015 |
| Almarc Property Limited | Real estate | 2016 |
| Almshouse Consortium Ltd | Administrative & support | 2011 |
| Aloe Imports (UK) Limited | Wholesale & retail | 1998 |
| Alpha 24/7 Recruit Services Ltd | Health & social care | 2017 |
| Alpha Auto Centre Ltd | Wholesale & retail | 2025 |
| Alpha Cars P&H Ltd | Transport & logistics | 2020 |
| Alpha Centauri Properties Ltd | Real estate | 2020 |
| Alpha Circuit Solutions Ltd | Construction | 2026 |
| Alpha Star Group Ltd | Wholesale & retail | 2023 |