| Adiphil Services Limited | Health & social care | 2016 |
| Adis Health Solutions Ltd | Health & social care | 2026 |
| Aditya V Limited | Health & social care | 2013 |
| Adiuvo Engineering & Training Ltd | Professional & scientific | 2014 |
| Adiuvo Events Ltd | Administrative & support | 2025 |
| ADJ Mgmt Ltd | Professional & scientific | 2022 |
| Adjustavista Ltd | Information & communication | 2022 |
| ADL Consultancy Ltd | Professional & scientific | 2018 |
| ADM Glass Limited | Construction | 2005 |
| Admee Ltd | Information & communication | 2019 |
| Adnk Stores Limited | Wholesale & retail | 2026 |
| Adonkia Ltd | Transport & logistics | 2014 |
| Adot Services Limited | Professional & scientific | 2020 |
| Adrat Consults Limited | Professional & scientific | 2022 |
| Adrian M5 Ltd | Transport & logistics | 2020 |
| Adroit Property Services Ltd | Real estate | 2022 |
| Adsul Limited | Information & communication | 2014 |
| Adsul Properties Ltd | Real estate | 2022 |
| Adunni Limited | Hospitality | 2021 |
| Advance Batting Academy Ltd | Arts & recreation | 2024 |
| Advance Cricket Academy Ltd | Wholesale & retail | 2024 |
| Advance House Services Ltd | Professional & scientific | 2013 |
| Advance Medical Consulting Services (Amcs) Limited | Administrative & support | 2023 |
| Advance Security Services Ltd | Administrative & support | 2025 |
| Advanced Apex Electrical Ltd | Construction | 2026 |
| Advanced Future Solutions Ltd | Mining & quarrying | 2024 |
| Advanced Psychological Solutions Ltd | Education | 2022 |
| Aegis Health Limited | Health & social care | 2026 |
| Aegis Legal Services Limited | Professional & scientific | 2025 |
| Aejc UK Ltd | Wholesale & retail | 2023 |
| Aekru Limited | Health & social care | 2025 |
| AEL Connection Ltd | Transport & logistics | 2024 |
| Aeon Property Limited | Construction | 2004 |
| Aerobite Limited | Wholesale & retail | 2021 |
| Aerotwin Ltd | Information & communication | 2025 |
| AF Plumbing Services Ltd | Construction | 2024 |
| AF Security Ltd | Construction | 2025 |
| AFA Management Ltd | Administrative & support | 2016 |
| AFB Steel Fixing Ltd | Construction | 2019 |
| Affainie Enterprise Limited | Information & communication | 2020 |
| Affinity Domestic Limited | Construction | 2021 |
| Affirmative Access Limited | Health & social care | 2023 |
| Afford-A-Floor Ltd | Construction | 2023 |
| Afloat Invest Ltd | Professional & scientific | 2026 |
| Afribelly Ltd | Hospitality | 2018 |
| Afriborder Ltd | Information & communication | 2013 |
| Afrikay Travel Ltd | Professional & scientific | 2024 |
| AFS Property Ltd | Real estate | 2022 |
| Afterbuilders Cleaning London Ltd | Administrative & support | 2014 |
| Aftersure Limited | Professional & scientific | 2025 |
| AG Completion Services Limited | Professional & scientific | 2021 |
| AG Home Builders Limited | Construction | 2022 |
| AG International Enterprise (Agile) Limited | Wholesale & retail | 2017 |
| Aganea Interiors Ltd | Manufacturing | 2021 |
| Agapestyling Limited | Wholesale & retail | 2025 |
| Agarwood Fragrances Ltd | Wholesale & retail | 2024 |
| Ageless Fuel Ltd | Wholesale & retail | 2025 |
| Ageless Therapy & Homecare Services Ltd | Health & social care | 2025 |
| Ageltec Limited | Manufacturing | 2002 |
| Agile Diffraction Ltd | Professional & scientific | 2017 |
| Agile Regulatory Consulting Ltd | Professional & scientific | 2022 |
| Agkk Ltd | Construction | 2025 |
| AGL Commercial Ltd | Construction | 2013 |
| AGO Utilities Limited | Construction | 2022 |
| Agora Cafe UK Ltd | Hospitality | 2015 |
| Agro Based Resources and Supplies (Abras) Limited | Wholesale & retail | 2010 |
| Agro Europe UK Limited | Administrative & support | 2017 |
| AGS Coachworks Ltd | Wholesale & retail | 2016 |
| Agujiegbe Global Ltd | Health & social care | 2022 |
| Agusto Enterprise Ltd | Health & social care | 2021 |
| Agyeisco Logistics Limited | Transport & logistics | 2026 |
| AH Managed Services Ltd | Administrative & support | 2016 |
| Ahava Impact Limited | Administrative & support | 2026 |
| AHL Healthcare Ltd | Information & communication | 2022 |
| Ahmati APN Limited | Construction | 2017 |
| AHS Horizon Learning Ltd | Professional & scientific | 2024 |
| AI SEO Software Solutions Ltd | Information & communication | 2025 |
| AI Trading Hub Limited | Information & communication | 2023 |
| AIC Transport Services Ltd | Transport & logistics | 2019 |
| Aido & Co Transport Limited | Transport & logistics | 2018 |
| Aika Medical Limited | Health & social care | 2025 |
| Aiko & Marie Publishing Ltd | Information & communication | 2021 |
| AIM Point Ltd | Hospitality | 2020 |
| Air Compressor Engineering Ltd | Manufacturing | 2009 |
| Airem Limited | Real estate | 2023 |
| Airiemiokhale Medical Services Ltd | Health & social care | 2026 |
| Airport Pickup Cars Ltd | Transport & logistics | 2025 |
| Airtravely Ltd | Administrative & support | 2024 |
| Aisl Holdings Limited | Financial services | 2025 |
| Aisosa Limited | Wholesale & retail | 2020 |
| AJ & Co. Construction Ltd | Construction | 2007 |
| AJ Aesthetics Essex Ltd | Other services | 2025 |
| AJ Beauty Salon Ltd | Other services | 2025 |
| AJ Core Physiotherapy Ltd | Health & social care | 2018 |
| AJ Global Goods Ltd | Wholesale & retail | 2025 |
| AJ Performance Recovery Ltd | Health & social care | 2025 |
| AJ Stays Ltd | Real estate | 2026 |
| AJB Medico Legal Ltd | Health & social care | 2024 |
| Ajbs Investments Ltd | Wholesale & retail | 2014 |
| AJC Construction Services Ltd | Construction | 2017 |