| Akksola Energy - Invest PLC | Professional & scientific | 2019 |
| Akksola Energy - North Ltd | Professional & scientific | 2019 |
| AKM Property Management Limited | Real estate | 2024 |
| Akom Services Limited | Administrative & support | 2018 |
| AKS Joinery Ltd | Construction | 2018 |
| AKS Late Shop Limited | Wholesale & retail | 2019 |
| Aktiva-Consulting Limited | Professional & scientific | 2015 |
| Aktiviti Ltd | Arts & recreation | 2022 |
| AL & V Properties Limited | Real estate | 2025 |
| AL Hajab Enterprises Ltd | Wholesale & retail | 2026 |
| AL Jazi Real Estate Limited | Construction | 2023 |
| Aladin Construction Network Limited | Construction | 2024 |
| Alaman Properties Ltd | Real estate | 2024 |
| Alan Fairhurst Construction Limited | Construction | 2019 |
| Alan Jones Funeral Directors Limited | Other services | 2012 |
| Alanth Ltd | Wholesale & retail | 2025 |
| Alarm Intruder Detection Ltd | Administrative & support | 1973 |
| ALB Motorbodies Limited | Wholesale & retail | 2014 |
| Albion Consultancy Ltd | Professional & scientific | 2015 |
| Albion UK RTM Ltd | Real estate | 2022 |
| Alborz WGN Ltd | Hospitality | 2025 |
| ALCAPONE96 Ltd | Hospitality | 2024 |
| Alchemy Tattoo Limited | Other services | 2016 |
| Alcohol Aware Limited | Extraterritorial | 2018 |
| Alcohol Treatment Solutions Ltd | Health & social care | 2014 |
| Alcorum | Professional & scientific | 2025 |
| ALD North West Ltd | Hospitality | 2026 |
| Aledu Medical Services Limited | Health & social care | 2012 |
| Alega Flexiclean Services Ltd | Administrative & support | 2025 |
| Alema Hair & Beauty Ltd | Other services | 2013 |
| Alesso Trading Limited | Wholesale & retail | 2015 |
| Alex Hughes Joinery Ltd | Construction | 2019 |
| Alexander House Associates Limited | Financial services | 2002 |
| Alexander House Property Management Limited | Real estate | 2020 |
| Alexander Stock Ltd | Professional & scientific | 2025 |
| Alexander William Properties Ltd | Real estate | 2024 |
| Alexanders Coffee Shop Ltd | Hospitality | 2019 |
| Alfa Anaesthetics Limited | Health & social care | 2019 |
| Alfa Contracting Ltd | Construction | 2025 |
| Alfiebear Ltd | Wholesale & retail | 2020 |
| Alfredo Wigan Ltd | Hospitality | 2022 |
| ALG Homes Limited | Real estate | 2011 |
| Algorithmic Trading Limited | Financial services | 2025 |
| Ali's Travel UK Ltd | Transport & logistics | 2020 |
| Align Design Agency Limited | Professional & scientific | 2014 |
| Alignher Ltd | Wholesale & retail | 2025 |
| Alin Healthcare Ltd | Health & social care | 2021 |
| Alina Nechita Limited | Professional & scientific | 2022 |
| Alinea Solutions Limited | Construction | 2022 |
| Alira Corp Ltd | Wholesale & retail | 2022 |
| Alison Aris Ltd | Administrative & support | 2016 |
| ALK Logistics Limited | Transport & logistics | 2025 |
| Alker Development Ltd | Construction | 2025 |
| Alker Rail Ltd | Construction | 2019 |
| ALL Ears MHA C.I.C. | Education | 2020 |
| ALL Round Care Ltd | Health & social care | 2017 |
| ALL Skills Central Limited | Administrative & support | 2025 |
| ALL Smiles Studio Ltd | Wholesale & retail | 2021 |
| ALL Trades 4 U Limited | Construction | 2020 |
| Allabella Craft Limited | Wholesale & retail | 2019 |
| Allcom (UK) Limited | Information & communication | 2006 |
| Allen Bros Fireplaces Limited | Manufacturing | 1996 |
| Alliance Construction Group Ltd | Construction | 2024 |
| Alliance Door Engineering Limited | Manufacturing | 2001 |
| Alliance Properties Group Ltd | Real estate | 2026 |
| Allied Holdings North West Ltd | Financial services | 2025 |
| Allied Insurance Services Limited | Financial services | 2001 |
| Allied Property Holdings Ltd | Real estate | 2025 |
| Allison Properties Limited | Real estate | 2016 |
| Allpoint Independent Services Ltd | Professional & scientific | 2024 |
| Allsopp Brazilian JIU Jitsu Ltd | Education | 2025 |
| Alltrax CIC | Information & communication | 2025 |
| Allverified Ltd | Wholesale & retail | 2022 |
| Ally Thompson Ltd | Other services | 2013 |
| Allyant Properties Limited | Hospitality | 2025 |
| ALM Joinery Limited | Construction | 2018 |
| ALM Prestige Bathrooms Ltd | Construction | 2025 |
| Almond Estates Management Limited | Real estate | 2024 |
| Almost Wild Community Interest Company | Health & social care | 2022 |
| Alocura Limited | Professional & scientific | 2016 |
| Alogfire Limited | Wholesale & retail | 2025 |
| Alongside Projects Ltd | Arts & recreation | 2025 |
| Alpha Holdings Nationwide Limited | Administrative & support | 2022 |
| Alpha Motors (Wigan) Limited | Wholesale & retail | 2000 |
| Alpha Sales and Customer Services Limited | Administrative & support | 2008 |
| Alpha Sheet Metal (North) Limited | Manufacturing | 1998 |
| ALPHA1000 Limited | Manufacturing | 2024 |
| Alphasierra Property Limited | Real estate | 2023 |
| Alpine Manufacturing Limited | Manufacturing | 2022 |
| ALR Paint and Body Ltd | Wholesale & retail | 2025 |
| Alrit Solutions Ltd | Information & communication | 2010 |
| Alrollers Limited | Manufacturing | 2007 |
| ALS Fibre Solutions Ltd | Information & communication | 2023 |
| ALS Fried Chicken Ltd | Hospitality | 2019 |
| Alticec | Professional & scientific | 2026 |
| Altisima Ltd | Professional & scientific | 2022 |
| Altruisk Limited | Other services | 2007 |
| Alucard Inchoate Limited | Information & communication | 1986 |
| Alurisal Ltd | Professional & scientific | 2026 |
| AM Call Cloud Limited | Administrative & support | 2025 |