| Albilaadi Community and Education Centre Limited | Education | 2015 |
| Albion Insulation Services Ltd | Construction | 2025 |
| Albi’S Cars Ltd | Wholesale & retail | 2025 |
| Albu GSG Construction Limited | Construction | 2020 |
| Albury Taste of Africa Limited | Wholesale & retail | 2025 |
| Albusoda Gastroenterology Ltd | Health & social care | 2019 |
| Albz Restaurant Ltd | Hospitality | 2022 |
| Alchemy Associates Ltd | Professional & scientific | 2000 |
| Alchemy Consult Limited | Real estate | 2002 |
| Alcon BSL Services Ltd | Professional & scientific | 2021 |
| Aldama Ltd | Construction | 2017 |
| Alderwood Barns Management Company Limited | Households | 2012 |
| Aldis of Barking Limited | Construction | 1946 |
| Aldus Accountants Limited | Professional & scientific | 2015 |
| Aleam Construction Limited | Construction | 2019 |
| Aleam Scaffolding Limited | Construction | 2020 |
| Alecuuu Ltd | Transport & logistics | 2025 |
| Aleda Consulting Ltd | Professional & scientific | 2012 |
| Alemur General Construction Ltd | Construction | 2021 |
| Alerivo Ltd | Wholesale & retail | 2025 |
| Alert Multi Services Ltd | Water & waste | 2016 |
| Alessia Prestige Limited | Transport & logistics | 2025 |
| Aleur Limited | Professional & scientific | 2014 |
| Aleva & Co Accountants Ltd | Professional & scientific | 2023 |
| Alevial Ltd | Wholesale & retail | 2023 |
| Alevoi Buildings Ltd | Construction | 2020 |
| Alex Building Services (UK) Limited | Construction | 2008 |
| Alex London Lofts Ltd | Construction | 2020 |
| Alex Perfect Fit Ltd | Construction | 2024 |
| ALEX98 Ltd | Construction | 2016 |
| Alexander Birch Ltd | Professional & scientific | 2025 |
| Alexdar Formwork Limited | Construction | 2015 |
| Alexeiix Limited | Transport & logistics | 2016 |
| Alexfitz Ltd | Construction | 2019 |
| Alexhost Ltd | Information & communication | 2020 |
| Alexis Group Construction Ltd | Construction | 2017 |
| Alexrogo Construction Ltd | Construction | 2019 |
| Alexyos Ltd | Construction | 2021 |
| Aleyna Story Ltd | Wholesale & retail | 2025 |
| Alfa Halal Food Distribution Ltd | Wholesale & retail | 2015 |
| Alfalah Consultants Limited | Manufacturing | 2009 |
| Alfie Electric Services Ltd | Construction | 2024 |
| Alfred Pointing and Restoration Ltd | Construction | 2022 |
| Algorion AI Ltd | Information & communication | 2024 |
| Algoritmi Tech Ltd | Information & communication | 2025 |
| Algovogue Limited | Information & communication | 2024 |
| Alhamdolillah Limited | Health & social care | 2023 |
| Alhuda Sales UK Ltd | Wholesale & retail | 2020 |
| ALI & Sons Construction Ltd | Construction | 2026 |
| ALI Baba Corporate Limited | Wholesale & retail | 2021 |
| ALI G Cafe & Grill Ltd | Hospitality | 2023 |
| ALI Hussain Property Ltd | Real estate | 2024 |
| ALI OOP Ltd | Information & communication | 2012 |
| ALI Panel Painting Ltd | Wholesale & retail | 2018 |
| Aliaj Construction Ltd | Construction | 2012 |
| Aliensoft Solutions Ltd | Wholesale & retail | 2025 |
| Alif Pre-Schools Ltd | Education | 2021 |
| Aligned Minds Limited | Administrative & support | 2003 |
| Alijack Limited | Arts & recreation | 2019 |
| Alim Live Ltd | Education | 2020 |
| Alin C Construction Ltd | Construction | 2021 |
| Alina Mirela Ancuta Limited | Professional & scientific | 2016 |
| Alina's Cleaning Ltd | Administrative & support | 2019 |
| Alinsorohan Ltd | Construction | 2024 |
| Alisha C Thomas Ltd | Professional & scientific | 2025 |
| Alita Construct Limited | Manufacturing | 2023 |
| Alive Events Limited | Professional & scientific | 2002 |
| Aliz Barberzz Ltd | Other services | 2024 |
| Aliza's Marketing Consultancy Ltd | Professional & scientific | 2018 |
| Aljazirah Newspaper Ltd | Professional & scientific | 2024 |
| Alkari Ltd | Real estate | 2019 |
| Alket Property Development Ltd | Real estate | 2026 |
| ALL About Tailormade Travel Limited | Administrative & support | 2011 |
| ALL Areas Scaffolding Services Ltd | Construction | 2026 |
| ALL Aspects Building Construction Ltd | Construction | 2020 |
| ALL Directions Services Ltd | Construction | 2015 |
| ALL Directions Transport Limited | Transport & logistics | 2018 |
| ALL European Bangabandhu Parishad Ltd | Other services | 2020 |
| ALL Fresh Retail Limited | Wholesale & retail | 2019 |
| ALL in 1 Electrical Solution Ltd | Manufacturing | 2015 |
| ALL in One Carpentry Limited | Construction | 2014 |
| ALL Natural Products Limited | Hospitality | 2021 |
| ALL of YOU Aesthetics and Beauty Ltd | Other services | 2025 |
| ALL Print Consultancy Ltd | Professional & scientific | 2025 |
| ALL Purpose Secondary Double Glazing Limited | Manufacturing | 2018 |
| ALL Roofing and Building Supplies Ltd | Wholesale & retail | 2024 |
| ALL Services London Ltd | Construction | 2025 |
| ALL Stars Property UK Ltd | Real estate | 2020 |
| ALL Traiding Ltd | Construction | 2024 |
| ALL Visionary Solutions Limited | Administrative & support | 2024 |
| ALL Ways Electrical Ltd | Construction | 2025 |
| ALLABOUTGATESANDAUTOMATION2 Ltd | Manufacturing | 2025 |
| Allah Limited | Wholesale & retail | 2023 |
| Allan & Mary Limited | Wholesale & retail | 2024 |
| Allanfield Limited | Wholesale & retail | 2018 |
| Allclear Holdings Limited | Professional & scientific | 2001 |
| Allclear Insurance Services Limited | Administrative & support | 2001 |
| Allen & Hall Motor Engineers Limited | Wholesale & retail | 2004 |
| Allen Analytics Limited | Information & communication | 2025 |
| Allen Contracting Ltd | Professional & scientific | 2024 |