| Active Cleaning Holiday Homes Limited | Other services | 2016 |
| Active Cleaningservices Ltd | Manufacturing | 2013 |
| Active Training Limited | Education | 2021 |
| Acua Ocean Limited | Manufacturing | 2020 |
| AD & Co Properties Ltd | Hospitality | 2024 |
| AD HOC Catering (Plymouth) Ltd | Hospitality | 2025 |
| Adam Atkinson Limited | Agriculture & fishing | 2012 |
| Adam Farley Ltd | Administrative & support | 2019 |
| ADC Accountants (South West) Ltd | Extraterritorial | 2015 |
| ADC SW Ltd | Manufacturing | 2015 |
| Adceed Limited | Other services | 2015 |
| ADD Agency London Ltd | Professional & scientific | 2021 |
| Adedayo Akinbowale Ltd | Public administration | 2024 |
| Adelaide Management SW Ltd | Real estate | 2025 |
| Adena's Catering Ltd | Hospitality | 2024 |
| ADF Plastics Limited | Construction | 2008 |
| ADI Dental Ltd | Health & social care | 2019 |
| Adifive Ltd | Manufacturing | 2024 |
| Adinkra Health Limited | Health & social care | 2019 |
| Adiuvare Limited | Health & social care | 2026 |
| Adjutor Solutions Limited | Real estate | 2011 |
| Adlocate Ltd | Information & communication | 2019 |
| Admdigi Ltd | Information & communication | 2025 |
| Admirals Hard Limited | Households | 1988 |
| Admirals Rest Limited | Real estate | 2021 |
| Admiralty Court Freehold Ltd | Real estate | 2015 |
| Admiralty House RTM Company Limited | Households | 2025 |
| Admiralty ROW (East END) RTM Company Limited | Households | 2025 |
| Admiralty Street Ltd | Administrative & support | 2017 |
| ADN Services Limited | Manufacturing | 2005 |
| Adorn Development Ltd | Real estate | 2020 |
| ADP Dental Laboratory Ltd | Health & social care | 2003 |
| ADR Property Solutions Ltd | Real estate | 2021 |
| Adrian Travel Ltd | Transport & logistics | 2026 |
| Adrian Verrin Electrical Ltd | Professional & scientific | 2017 |
| Adrivalb Ltd | Transport & logistics | 2026 |
| ADS Motorcycles Ltd | Wholesale & retail | 2024 |
| ADS Window Films Limited | Administrative & support | 2002 |
| Adtec Systems Limited | Manufacturing | 2002 |
| Advance Consulting Engineers Ltd | Professional & scientific | 2020 |
| Advanced Construction 360 Ltd | Construction | 2025 |
| Advanced Property Services (South West) Limited | Construction | 2014 |
| Advanced Underwater Systems Limited | Administrative & support | 2017 |
| Advantage Property Services Ltd | Administrative & support | 2022 |
| Advantix Automation Solutions Limited | Energy | 2016 |
| Adventure Golf Solutions Limited | Construction | 2019 |
| Adwalkersnationwide.Com Limited | Professional & scientific | 2015 |
| ADZ Property Developments Ltd | Construction | 2025 |
| Adzbel Ltd | Professional & scientific | 2026 |
| AEC Construction Group (Holdings) Limited | Financial services | 2026 |
| AEC Construction Holdings Limited | Financial services | 2026 |
| Aedo Studios Ltd | Information & communication | 2024 |
| Aegea Global (UK) Limited | Wholesale & retail | 2024 |
| Aegis FM Ltd | Administrative & support | 2019 |
| AEM Home Improvements & Maintenance Limited | Construction | 2011 |
| AEM South West Ltd | Professional & scientific | 2025 |
| Aerial Allsorts Development Programme Limited | Arts & recreation | 2019 |
| Aerial Allsorts Limited | Arts & recreation | 2017 |
| Aerial Contact Ltd | Construction | 2019 |
| Aeroav Services Ltd | Manufacturing | 2023 |
| Aesc Gunnr Limited | Real estate | 2026 |
| Aeson Consulting Limited | Professional & scientific | 2010 |
| Aestheta Limited | Health & social care | 2021 |
| Aesthetic & Laser Clinic Limited | Health & social care | 2014 |
| Aether Forge Games Ltd | Information & communication | 2022 |
| Aethereon Technologies Limited | Professional & scientific | 2025 |
| AF Bathroom & Heating Ltd | Construction | 2021 |
| Affinia Group Ltd | Professional & scientific | 2023 |
| Affinity Industries Limited | Wholesale & retail | 2020 |
| Affordable Waste Services Ltd | Water & waste | 2024 |
| AFG Plymouth Food Ltd | Hospitality | 2025 |
| Afri-Stitches UK Ltd | Manufacturing | 2025 |
| African Angels Collective Limited | Financial services | 2022 |
| African Delight 2 CIC | Hospitality | 2025 |
| African Delight Ltd | Hospitality | 2022 |
| African Grocery Ltd | Wholesale & retail | 2018 |
| Afro Plates Ltd | Hospitality | 2025 |
| Afrofresh Market Ltd | Wholesale & retail | 2026 |
| Aftl Limited | Information & communication | 2025 |
| AG Bazaar Ltd | Wholesale & retail | 2023 |
| AG Bookkeeping UK Ltd | Professional & scientific | 2025 |
| AG Nova Ltd | Wholesale & retail | 2022 |
| Agaciro Health Ltd | Administrative & support | 2025 |
| AGB Venure Ltd | Transport & logistics | 2024 |
| AGE Less Medical Ltd | Health & social care | 2025 |
| AGE Less. Botox and Dermal Fillers Ltd | Health & social care | 2010 |
| Ageless Cosmetics (Norfolk) Limited | Health & social care | 2016 |
| Agenda Platforms Ltd | Information & communication | 2025 |
| Aggiss & Easterbrook Ltd | Real estate | 2016 |
| Aghobimotos Limited | Real estate | 2026 |
| Agile Comms Ltd | Information & communication | 2021 |
| Agile Solar Ltd | Construction | 2022 |
| Agile Supply Chain Recruitment Limited | Administrative & support | 2019 |
| Agile Testing Solutions Limited | Information & communication | 2012 |
| Agilitatem Limited | Real estate | 2017 |
| Agrihanova UK Limited | Wholesale & retail | 2025 |
| Ahimsa | Other services | 1989 |
| AI Animation Ltd | Information & communication | 2024 |
| AI Trading Group Ltd | Extraterritorial | 2024 |
| Aibg Property Ltd | Real estate | 2024 |