| Allens Maintenance Services Limited | Manufacturing | 2013 |
| Allergy and Immunology Clinics Ltd | Health & social care | 2017 |
| Alles Tech Ltd | Wholesale & retail | 2024 |
| Allfilm Limited | Information & communication | 2024 |
| Alliance Caring Ltd | Health & social care | 2018 |
| Alliance Fire Consultants Ltd | Construction | 2024 |
| Alliance Housing Support Ltd | Health & social care | 2019 |
| Alliance K9 Ltd | Administrative & support | 2017 |
| Alliance Propco Ltd | Real estate | 2023 |
| Allied Aluminium Systems Ltd | Manufacturing | 2024 |
| Allied Sales Group Limited | Wholesale & retail | 2026 |
| Allied Snooker Limited | Administrative & support | 2002 |
| Allison E Cowen Limited | Professional & scientific | 2015 |
| Allman Property Ltd | Real estate | 2016 |
| Allora Supplies Ltd | Wholesale & retail | 2025 |
| Allotment Bar 71 by Lounge Bars Limited | Hospitality | 2025 |
| Allott Engineering Ltd | Professional & scientific | 2025 |
| Allott Enterprises (Trading AS Oakhouse Foods) Limited | Hospitality | 2013 |
| Alloy Analysis Limited | Professional & scientific | 2010 |
| Alloy DR Ltd | Manufacturing | 2025 |
| Alloy-D Wheel Refurbishment Ltd | Other services | 2016 |
| Allpumps Limited | Manufacturing | 1986 |
| Allrounder Cricket Ltd | Wholesale & retail | 2011 |
| Allsorts and More Limited | Wholesale & retail | 2024 |
| Allstore International Limited | Wholesale & retail | 2024 |
| Alltherapy Limited | Information & communication | 2024 |
| Alltread Tyres and Powder Coating Services Ltd | Wholesale & retail | 2025 |
| Allum Automation Ltd | Information & communication | 2011 |
| Allura Medical Ltd | Education | 2020 |
| Allure Clinic Limited | Health & social care | 2009 |
| Allwell Care Company Ltd | Other services | 2017 |
| Ally Zetterberg Literary Limited | Arts & recreation | 2022 |
| ALM Analytics & Consultancy Limited | Professional & scientific | 2018 |
| Alma Hospitality Ltd | Hospitality | 2019 |
| Almahra Limited | Health & social care | 2024 |
| Almarai Ltd | Wholesale & retail | 2020 |
| Almaydah Ltd | Wholesale & retail | 2025 |
| Almeda Homes Ltd | Construction | 2018 |
| Almost ALL Digital Ltd | Information & communication | 2017 |
| Almwy Ltd | Hospitality | 2024 |
| ALN Plastering & Renovations Ltd | Construction | 2019 |
| Alnair Tech Limited | Information & communication | 2006 |
| Alnasim Restaurant Limited | Hospitality | 2022 |
| ALO Deliveries Ltd | Transport & logistics | 2016 |
| Aloe Software Ltd | Information & communication | 2019 |
| Aloha Logistics Limited | Administrative & support | 2007 |
| Alouise Limited | Manufacturing | 2020 |
| ALP Entertainments Ltd | Information & communication | 2023 |
| Alpaslan Limited | Health & social care | 2024 |
| Alpet Ltd | Transport & logistics | 2025 |
| Alpg Consulting Services Limited | Professional & scientific | 2007 |
| ALPH4 Limited | Information & communication | 2019 |
| Alpha 786 Limited | Real estate | 2023 |
| Alpha Accounting Services Limited | Professional & scientific | 1995 |
| Alpha and Omega Church CIC | Education | 2023 |
| Alpha Consulting SK Limited | Information & communication | 2022 |
| Alpha Digital Solutions Limited | Information & communication | 2001 |
| Alpha Labour and Recruitment Limited | Administrative & support | 2008 |
| Alpha Medical International Holdings Ltd | Financial services | 2026 |
| Alpha MOT & Service Centre Limited | Wholesale & retail | 2002 |
| Alpha Plus Limited | Administrative & support | 1999 |
| Alpha Plus RGM Limited | Professional & scientific | 2011 |
| Alpha Plus Topco Limited | Financial services | 2022 |
| Alpha Punch and Machinery Limited | Manufacturing | 2007 |
| Alpha Safe Cover Limited | Hospitality | 2023 |
| Alpha SI Limited | Health & social care | 2025 |
| Alpha Specialist Services Ltd | Professional & scientific | 2022 |
| Alpha Staff Training Ltd | Administrative & support | 2010 |
| Alpha Start Limited | Hospitality | 2019 |
| Alpha Taurus Ltd | Wholesale & retail | 2026 |
| ALPHA21 Ltd | Education | 2022 |
| Alphabet Sign Makers Ltd | Professional & scientific | 2011 |
| Alphaeventservices Ltd | Hospitality | 2025 |
| Alphamax Digital Limited | Real estate | 2022 |
| Alpine Guides Ltd | Arts & recreation | 2003 |
| Alpp Ltd | Real estate | 2022 |
| Alpsychology Ltd | Education | 2023 |
| Alqabati Cafeteria Limited | Hospitality | 2025 |
| Alraha Cafe Limited | Hospitality | 2026 |
| Alsaadi Limited | Financial services | 2026 |
| Alsaso Properties Ltd | Real estate | 2017 |
| Alshifa Direct Limited | Health & social care | 2014 |
| Alshurbasi Ltd | Health & social care | 2024 |
| Alsindbad Ltd | Manufacturing | 2020 |
| Also Known AS Limited | Manufacturing | 2005 |
| Alsoltan Limited | Hospitality | 2024 |
| Alstays Ltd | Real estate | 2025 |
| Alsung Ltd | Information & communication | 2024 |
| ALT TAB EST Ltd | Hospitality | 2025 |
| Altai Enterprise Ltd | Information & communication | 2024 |
| Alterna Renewables Ltd | Construction | 2024 |
| Altitude Luxury Travel Limited | Administrative & support | 2009 |
| Altiyar Ltd | Administrative & support | 2015 |
| Altofix Limited | Construction | 2006 |
| Alton & James Limited | Health & social care | 2015 |
| Alton Building Services Limited | Construction | 2012 |
| Alton Fork Truck Services Limited | Administrative & support | 2003 |
| Alton House Management Company Limited | Households | 2008 |
| Alton Shop Ltd | Wholesale & retail | 2025 |
| Altres Talent Ltd | Administrative & support | 2024 |