| A2A Catering Limited | Hospitality | 2026 |
| A2I LDN Limited | Other services | 2018 |
| A2Z Cars Limited | Transport & logistics | 2012 |
| A2Z Constructions & Heating Ltd | Construction | 2018 |
| A2Z Express Mobile Tyres Ltd | Wholesale & retail | 2021 |
| AA Heights Developers Ltd | Real estate | 2023 |
| AA Plus Transport Ltd | Transport & logistics | 2026 |
| AA Property & Lettings Management Ltd | Real estate | 2018 |
| AA Property Management Service Ltd | Real estate | 2025 |
| AAA2 Properties Ltd | Real estate | 2025 |
| Aadhya Trading Limited | Wholesale & retail | 2025 |
| Aadi's UK Ltd | Other services | 2014 |
| AAI Enterprises Limited | Wholesale & retail | 2026 |
| Aathuren Limited | Hospitality | 2026 |
| AB Mini CAB Limited | Transport & logistics | 2021 |
| Abakar Ltd | Transport & logistics | 2025 |
| Abatz Supply Ltd | Construction | 2019 |
| Abazu Source Ltd | Construction | 2019 |
| ABE Commercial Ltd | Hospitality | 2016 |
| ABJ & KS Security Services Limited | Administrative & support | 2026 |
| Ablat Ltd | Real estate | 2024 |
| Absid Ltd | Construction | 2025 |
| Abundance Equity Limited | Construction | 2026 |
| AC First Limited | Real estate | 2019 |
| AC Professional Business Services Limited | Real estate | 2018 |
| AC Professional Consulting Services Limited | Health & social care | 2017 |
| AC Professional Freehold Services Limited | Real estate | 2023 |
| AC Professional Joint Services Limited | Real estate | 2020 |
| AC Professional Management Services Limited | Real estate | 2017 |
| AC Professional Services Ltd | Extraterritorial | 2024 |
| AC1 Ltd | Real estate | 2025 |
| ACA Properties Investment Ltd | Real estate | 2021 |
| Academy Hair and Beauty (UK) Ltd | Manufacturing | 1997 |
| Academy of Brilliance Ltd | Education | 2025 |
| Access Life Management Ltd | Professional & scientific | 2025 |
| Access Wellness Ltd | Education | 2025 |
| Accollins Ltd | Professional & scientific | 2024 |
| Accounting Placements Ltd | Administrative & support | 2020 |
| Accsellera Ltd | Information & communication | 2024 |
| Accudents Ltd | Professional & scientific | 2019 |
| Ace Construction Crew Ltd | Construction | 2015 |
| Acecone Limited | Professional & scientific | 2000 |
| Acedev Ltd | Information & communication | 2021 |
| ACL & Co (London) Ltd | Professional & scientific | 2022 |
| ACM Motors Ltd | Wholesale & retail | 2025 |
| ACN Builders Ltd | Construction | 2021 |
| Active Future Sutton CIC | Education | 2025 |
| Activeman Construction Limited | Construction | 2024 |
| Adade Group Ltd | Households | 2025 |
| Adam Mawi Chauffeur Services Ltd | Other services | 2019 |
| ADD Union Limited | Construction | 2023 |
| Ade-Law Consultancy Limited | Professional & scientific | 2022 |
| Adeyemo & Sons Ltd | Wholesale & retail | 2025 |
| Adeys Personal Shopper Limited | Other services | 2021 |
| ADI Veli Limited | Manufacturing | 2024 |
| Adi's Local Limited | Wholesale & retail | 2013 |
| Adjumako Cleaning Service Ltd | Administrative & support | 2022 |
| Admoss Company Limited | Professional & scientific | 2025 |
| Admprop.Co.Uk Ltd | Construction | 2012 |
| ADN Solutions Limited | Wholesale & retail | 2015 |
| Adorne Events Ltd | Professional & scientific | 2018 |
| Adr.P Ltd | Construction | 2021 |
| Adriano Mobile Device Management (Amdm) Limited | Professional & scientific | 2022 |
| Adriano Properties Ltd | Professional & scientific | 2014 |
| Adur Properties Ltd | Real estate | 2025 |
| Aeroheat GAS Ltd | Construction | 2025 |
| Affan Business Enterprises Limited | Administrative & support | 2024 |
| Affluence Global Dreams UK Limited | Wholesale & retail | 2024 |
| Affordable Lace Front Wigs Ltd | Wholesale & retail | 2010 |
| Affordable Property Group Management Ltd | Construction | 2019 |
| AFG Sarafi Ltd | Financial services | 2019 |
| Afrakomaa Service Limited | Health & social care | 2023 |
| African Caribbean Leukaemia Trust | Health & social care | 2003 |
| African Supermarket Ltd | Wholesale & retail | 2022 |
| Afrik Services Limited | Other services | 2023 |
| Afrobiome Ltd | Health & social care | 2025 |
| Afruika Bantu Saturday School CIC | Education | 2015 |
| AGC Electrics Ltd | Construction | 2017 |
| AGE UK Croydon | Health & social care | 2000 |
| AGE UK Croydon Trading Limited | Health & social care | 2006 |
| Aglow Health Solutions Ltd | Health & social care | 2020 |
| Agrisync Private Limited | Agriculture & fishing | 2025 |
| AH& an Holdings Limited | Real estate | 2020 |
| AHA Beauty Limited | Wholesale & retail | 2021 |
| Ahana Kothiya Consultancy Limited | Education | 2025 |
| AHN Solutions Ltd | Information & communication | 2024 |
| AHQ Consultancy Services Ltd | Information & communication | 2023 |
| AHQ Ltd | Wholesale & retail | 2022 |
| Ahsan ALI Tiktok Shop Ltd | Wholesale & retail | 2025 |
| Aiartist Limited | Professional & scientific | 2025 |
| AIE Group Limited | Financial services | 2024 |
| Aimee-Blu Management Ltd | Professional & scientific | 2024 |
| AIMSTECH786 Ltd | Other services | 2020 |
| Airon Construction Ltd | Construction | 2016 |
| Aiwanose Limited | Health & social care | 2026 |
| Aiyyappa Ltd | Wholesale & retail | 2012 |
| Aj's Traders Limited | Transport & logistics | 2019 |
| Ajayi Construction Limited | Professional & scientific | 2011 |
| Ajitunu Global Limited | Construction | 2021 |
| Ajones Co-Living Ltd | Real estate | 2019 |