| ALL Clear Dental Limited | Wholesale & retail | 2008 |
| ALL Cooling Limited | Professional & scientific | 2009 |
| ALL Cylinders Ltd | Wholesale & retail | 2019 |
| ALL Epic Welding Services Ltd | Construction | 2020 |
| ALL Family Matters Solicitors Limited | Professional & scientific | 2020 |
| ALL for Care Limited | Health & social care | 2025 |
| ALL Good Properties Limited | Real estate | 2005 |
| ALL Healthy Ltd | Wholesale & retail | 2024 |
| ALL in One Driving School Limited | Education | 2026 |
| ALL Metal Supplies Ltd | Water & waste | 2025 |
| ALL PS Property Ltd | Real estate | 2023 |
| ALL Purpose Supplies Ltd | Wholesale & retail | 2020 |
| ALL Rohit Accounting Ltd | Professional & scientific | 2016 |
| ALL Saints' Trust | Education | 2015 |
| ALL Star Care Limited | Health & social care | 2016 |
| ALL Things Considered Studio Ltd | Professional & scientific | 2025 |
| ALL Utility Collections Ltd | Administrative & support | 2025 |
| ALL Zakatek Music Limited | Information & communication | 1996 |
| ALL2CONSTRUCT Ltd | Manufacturing | 2024 |
| Allanby Developments 2000 Limited | Real estate | 1997 |
| Allbooks Limited | Manufacturing | 2018 |
| Allcare Cleaning Services Ltd | Administrative & support | 2026 |
| Allcare Properties Ltd | Hospitality | 2016 |
| Allconstruct Badea Ltd | Construction | 2023 |
| Allegro Blinds Ltd | Wholesale & retail | 2002 |
| Allen's of Mayfair Limited | Real estate | 1963 |
| Allen's of Victoria Limited | Real estate | 2016 |
| Allendale Ventures Limited | Wholesale & retail | 2016 |
| Allfor Care (Croydon) Limited | Health & social care | 2025 |
| Allfor Care (Doncaster) Limited | Health & social care | 2025 |
| Allfor Care (Hammersmith) Limited | Health & social care | 2025 |
| Allfor Care (Haringay) Limited | Health & social care | 2025 |
| Allfor Care (Hounslow) Limited | Health & social care | 2025 |
| Allgdp Ltd | Hospitality | 2024 |
| Allgo Construction Limited | Construction | 2024 |
| Allgrund Limited | Real estate | 2004 |
| Alliage Limited | Professional & scientific | 2019 |
| Alliance Auto Trading Limited | Wholesale & retail | 2018 |
| Alliance Care Solutions Limited | Health & social care | 2006 |
| Alliance Traffic Systems UK Ltd | Administrative & support | 2020 |
| Alliancevisas Limited | Professional & scientific | 2012 |
| Allied Accountings Ltd | Other services | 2017 |
| Allied Africa Group Ltd | Professional & scientific | 2025 |
| Allied Automation and Software Solutions Limited | Information & communication | 2023 |
| Allied Property Group Holdings 1 Limited | Real estate | 2025 |
| Allied Unity Ltd | Real estate | 2018 |
| Allied Vehicle Deliveries Limited | Other services | 2001 |
| Allo Technologies Ltd | Information & communication | 2021 |
| Allomcare Ltd | Real estate | 2025 |
| Allrite Limited | Hospitality | 2012 |
| Allset Go Accounting Ltd | Information & communication | 2026 |
| Allshop Wholesale UK Limited | Wholesale & retail | 2023 |
| Allstar Services Limited | Manufacturing | 1984 |
| Allstone Partners Ltd | Real estate | 2025 |
| Allstunts Inc Equipment Limited | Arts & recreation | 2007 |
| Allterix Limited | Wholesale & retail | 2026 |
| Alltravels Ltd | Wholesale & retail | 2023 |
| Allure Boutique London Limited | Wholesale & retail | 2024 |
| Alluring Spirituality Limited | Wholesale & retail | 2024 |
| Allwin Technologies Ltd | Administrative & support | 2017 |
| Allwinds Ground Maintenance Ltd | Administrative & support | 2013 |
| Allx Ltd | Financial services | 2014 |
| Allygrow Technologies UK Limited | Information & communication | 2015 |
| ALM Pictures Limited | Information & communication | 2008 |
| Alma Enterprise Ltd. | Construction | 2015 |
| Alma Mater V Ltd | Professional & scientific | 2015 |
| Alma Orthodontics Ltd | Health & social care | 2023 |
| Almaghreb Arabi Butchers Ltd | Wholesale & retail | 2022 |
| Almaro Limited | Professional & scientific | 2025 |
| Almas Global Production Limited | Information & communication | 2018 |
| Almaz Lounge Limited | Hospitality | 2016 |
| Almaz Restaurant Ltd | Hospitality | 2023 |
| Alminbar TV Limited | Information & communication | 2017 |
| Almond Care Providers Ltd | Health & social care | 2013 |
| Almond Eyecare Ltd | Wholesale & retail | 2024 |
| Almond Foods Ltd | Wholesale & retail | 2025 |
| Almustafa Centre CIC | Education | 2026 |
| ALN Venture Limited | Hospitality | 2022 |
| Alnimr Ltd | Administrative & support | 2024 |
| Alno Construction Ltd | Construction | 2022 |
| ALO Elites Ltd | Construction | 2026 |
| Aloa Limited | Professional & scientific | 2010 |
| Aloe Beauty Ltd | Other services | 2024 |
| Alokozai Ltd | Administrative & support | 2017 |
| Alomcare Academy Ltd | Education | 2019 |
| Alomcare Services Ltd | Real estate | 2021 |
| Along Came Mary Holdings Limited | Real estate | 2015 |
| Along Came Mary Ltd. | Administrative & support | 2006 |
| Alora Group Ltd | Construction | 2022 |
| Aloris EF Limited | Administrative & support | 2024 |
| Aloura London Limited | Wholesale & retail | 2015 |
| ALP Housing Ltd | Real estate | 2025 |
| ALP Prestige Ltd | Transport & logistics | 2017 |
| ALP Property Care Ltd | Construction | 2025 |
| Alpa Catering Ltd | Hospitality | 2025 |
| Alpan Limited | Transport & logistics | 2019 |
| Alpha Advisory Ltd | Information & communication | 2007 |
| Alpha AIM Distribution Ltd | Manufacturing | 2024 |
| Alpha Air Handling Services Ltd | Construction | 2021 |
| Alpha Beta Construction Limited | Construction | 2019 |