| Advantiq Limited | Administrative & support | 2019 |
| Advent PM Ltd | Other services | 2020 |
| Adventure Builders Limited | Construction | 2017 |
| Adventure Developers Ltd | Real estate | 2025 |
| Adventure Haulage Ltd | Transport & logistics | 2024 |
| Advi Consulting Limited | Information & communication | 2015 |
| Advice Sale Performance Limited | Wholesale & retail | 2014 |
| Advise YOU Ltd | Financial services | 2023 |
| AE Contracting Ltd | Administrative & support | 2013 |
| AE Fruits International Ltd | Hospitality | 2017 |
| AEC OFF Wing Limited | Manufacturing | 2017 |
| Aeircon Limited | Energy | 2025 |
| AEM Courier & Logistics Ltd | Transport & logistics | 2026 |
| Aeon Security Ltd | Administrative & support | 2018 |
| Aero Cargo (UK) Ltd | Transport & logistics | 2012 |
| Aero Engine Centre Limited | Transport & logistics | 2017 |
| Aero Time Critical Ltd | Transport & logistics | 2024 |
| Aerobus Maintenance Limited | Manufacturing | 2020 |
| Aerodrome Enterprise Ltd | Wholesale & retail | 2024 |
| Aerofixx Aviation Ltd | Wholesale & retail | 2026 |
| Aeromec Ltd | Manufacturing | 2020 |
| Aeroquip-Vickers Limited | Professional & scientific | 1983 |
| Aerospec Solutions Ltd | Professional & scientific | 2010 |
| AES Consultancy Limited | Professional & scientific | 2014 |
| AES London Limited | Other services | 2019 |
| Aesthetic Beauty Clinic Limited | Other services | 2025 |
| Aesthetics Refined Clinics Limited | Other services | 2015 |
| Aesthetics Refined Limited | Extraterritorial | 2017 |
| Aesthetix Systems Ltd | Information & communication | 2026 |
| Aetas Prime Ltd | Health & social care | 2023 |
| Aevis Consultancy Ltd | Information & communication | 2020 |
| Aevitas Biopharma Co Ltd | Wholesale & retail | 2019 |
| Aevum Trading Ltd | Wholesale & retail | 2025 |
| AEY Exports Ltd | Wholesale & retail | 2025 |
| AF Millar Holdings Limited | Information & communication | 2024 |
| AFF Limited | Wholesale & retail | 2025 |
| Affordable Photography Ltd | Professional & scientific | 2024 |
| Afghan Bakery Ltd | Manufacturing | 2016 |
| Afiyah Naturals Ltd | Wholesale & retail | 2025 |
| AFL (Fleet Management) Ltd | Administrative & support | 2011 |
| AFM Civil Engineering Limited | Construction | 2014 |
| Afnas Online Ltd | Wholesale & retail | 2024 |
| AFR Tech Limited | Other services | 2017 |
| AFR Trading Ltd | Other services | 2013 |
| Afridi Motors Ltd | Wholesale & retail | 2019 |
| Afro Good Looks Saloon Ltd | Other services | 2023 |
| Afro Masters Ltd | Wholesale & retail | 2024 |
| Afro Nation Business Ltd | Professional & scientific | 2024 |
| Afsar Enterprise Ltd | Wholesale & retail | 2020 |
| Afterlyfe Ltd | Professional & scientific | 2025 |
| AFW Property Management Ltd | Real estate | 2025 |
| Afzaal Brothers Ltd | Real estate | 2022 |
| AG & Co UK Ltd | Wholesale & retail | 2025 |
| AG Collaboration Full Service Marketing Limited | Professional & scientific | 2017 |
| AG Fire Protection Ltd | Public administration | 2026 |
| AG Property Group Ltd | Real estate | 2026 |
| AGA Builders Ltd | Construction | 2025 |
| Agam Avnoor Limited | Transport & logistics | 2019 |
| Agam Electrics Ltd | Construction | 2020 |
| Agam Gill Properties Ltd | Real estate | 2025 |
| Agan Properties Limited | Extraterritorial | 2025 |
| Agastya Tech Consulting Limited | Information & communication | 2025 |
| Agate Group Limited | Real estate | 2026 |
| AGDANGAN64 Limited | Health & social care | 2020 |
| Aged LDN Ltd | Wholesale & retail | 2025 |
| Agency 14 Ltd | Administrative & support | 2024 |
| Agenex Ltd | Professional & scientific | 2023 |
| Aggars Direct Limited | Administrative & support | 2013 |
| Aggarwal Property Investments Ltd | Real estate | 2019 |
| AGH Holdings (Berkshire) Ltd | Hospitality | 2022 |
| Aghs Accounting & Taxation Services Limited | Professional & scientific | 2010 |
| AGI Ecommerce Ltd | Wholesale & retail | 2020 |
| Agile Flowmotion Ltd | Information & communication | 2023 |
| Agile Gurukul PVT Limited | Administrative & support | 2012 |
| Agile Software Consulting Ltd | Information & communication | 2011 |
| Agilebits UK Limited | Administrative & support | 2020 |
| Agilevan Ltd | Information & communication | 2023 |
| Agility Ahead Ltd | Information & communication | 2019 |
| AGM Distribution Limited | Wholesale & retail | 2025 |
| AGM247 Interiors Ltd | Construction | 2020 |
| Agnesiu Ltd | Wholesale & retail | 2020 |
| Agness Limited | Wholesale & retail | 2025 |
| Agnodice Gynaecology Ltd | Health & social care | 2021 |
| Agog Car Solutions Ltd | Wholesale & retail | 2025 |
| Agricolo Lighting & Electrical Limited | Information & communication | 2025 |
| Agrolist Group Ltd | Information & communication | 2025 |
| Agromparts Ltd | Wholesale & retail | 2024 |
| Agsd Properties Limited | Real estate | 2017 |
| Agyakoma HC Ltd | Health & social care | 2019 |
| AH Perfect Pizza Ltd | Hospitality | 2022 |
| AH3 Heating & Plumbing Solutions Ltd | Construction | 2012 |
| AHA Enterprises Ltd | Administrative & support | 2025 |
| AHA International Ltd | Wholesale & retail | 2022 |
| Aha&Co Ltd | Construction | 2021 |
| Ahad Engineering Consultant Ltd | Professional & scientific | 2019 |
| Ahad Security Limited | Administrative & support | 2017 |
| Ahadioperations Ltd | Wholesale & retail | 2026 |
| Ahaz Corporation Ltd | Manufacturing | 2024 |
| Ahead Rigging Ltd | Information & communication | 2011 |
| Ahhs Enterprises Ltd | Wholesale & retail | 2021 |