| A T Coaches Ltd | Transport & logistics | 2005 |
| A Table for Three Ltd | Information & communication | 2024 |
| A W Consulting Limited | Professional & scientific | 1999 |
| A Y BBQ Ltd | Hospitality | 2023 |
| A&C LUX Rides London Ltd | Transport & logistics | 2026 |
| A&C Trans Ltd | Transport & logistics | 2025 |
| A&D Advisory Ltd | Professional & scientific | 2024 |
| A&G Dentures Ltd | Administrative & support | 2022 |
| A&G Paving Ltd | Construction | 2018 |
| A&M Partnership Limited | Real estate | 2019 |
| A-Team Family Investments Ltd | Real estate | 2022 |
| A-Xceed Ltd | Real estate | 2021 |
| A. O. OWA & Associates Limited | Health & social care | 2026 |
| A.1 Taxis of Ilford Limited | Transport & logistics | 1975 |
| A.J.H.D Property Ltd | Real estate | 2025 |
| A.P. Craft Ltd | Construction | 2026 |
| A1 Phones & Gadgets Ltd | Wholesale & retail | 2019 |
| A2Z Vehicle Services Limited | Administrative & support | 2025 |
| AA & RA Investments Limited | Real estate | 2024 |
| AA Commercial Property Ltd | Real estate | 2020 |
| AA Industrial Property Ltd | Agriculture & fishing | 2020 |
| AA Land Development Ltd | Real estate | 2020 |
| AA Plumbing & Heating Engineers Ltd | Other services | 2011 |
| Aa&Mi Ltd | Hospitality | 2021 |
| AA13 Limited | Financial services | 2019 |
| AAA Deseert Co Ltd | Hospitality | 2024 |
| AAA Kingston Ltd | Other services | 2018 |
| AAE Management Services Limited | Information & communication | 2015 |
| AAK Lettings Ltd | Real estate | 2025 |
| AAK UK Services Limited | Wholesale & retail | 2026 |
| Aaplumbing&Heating Ltd | Construction | 2019 |
| Aara Retail Ltd | Wholesale & retail | 2018 |
| Aari Smiles Ltd | Health & social care | 2024 |
| Aarks Overseas Ltd | Transport & logistics | 2024 |
| Aaron Wheeler Holdings Limited | Financial services | 2021 |
| Aaron Wheeler Limited | Administrative & support | 2005 |
| Aaru Consulting Limited | Administrative & support | 2025 |
| Aayana Limited | Wholesale & retail | 2021 |
| Abadvice Limited | Financial services | 2016 |
| Abakas Services Limited | Professional & scientific | 2017 |
| ABB International Ltd | Wholesale & retail | 2023 |
| Abbey Travel Coaches Ltd | Transport & logistics | 2021 |
| Abbots Home Limited | Administrative & support | 2021 |
| Abhi Properties PVT Ltd | Real estate | 2018 |
| ABI Boxing Intensive Ltd | Arts & recreation | 2019 |
| Abiagu Ltd | Health & social care | 2025 |
| Ablenew Limited | Real estate | 1996 |
| Ableside Limited | Construction | 2006 |
| Abmn Ltd | Hospitality | 2017 |
| ABN Finance & Leasing (Essex) Ltd | Financial services | 2013 |
| ABN Finance & Leasing (Herts) Ltd | Financial services | 2013 |
| ABN Finance & Leasing Limited | Financial services | 2001 |
| Abou Zolof Limited | Construction | 2024 |
| About Alpha Ltd | Information & communication | 2023 |
| ABR London Clinics Ltd | Health & social care | 2023 |
| Absolute Electrics & Audio Visual Systems Limited | Construction | 2010 |
| Absolute Speed Meters Ltd | Professional & scientific | 2019 |
| Aburana Ltd | Wholesale & retail | 2025 |
| Abzy Property Limited | Real estate | 2026 |
| Academia & Football Ltd | Education | 2022 |
| Acap Private Equity Limited | Information & communication | 2006 |
| Acaps Holdings Ltd | Financial services | 2020 |
| Accepted Charity Limited | Education | 2014 |
| Accounting and Taxation London Ltd | Professional & scientific | 2023 |
| Accountswise Accountants Ltd | Professional & scientific | 2010 |
| Accountswise Taxadvisers Ltd | Professional & scientific | 2022 |
| Accurat Contractor&Services Ltd | Administrative & support | 2019 |
| Accurat Pest Solutions Limited | Administrative & support | 2018 |
| Accurate Trader Ltd | Wholesale & retail | 2024 |
| Ace Discos Limited | Arts & recreation | 2003 |
| Ace of Clubs Limited | Wholesale & retail | 2026 |
| Aceditor Limited | Information & communication | 2003 |
| Aceso Care Ltd | Health & social care | 2024 |
| Achieve Holdings Limited | Administrative & support | 2018 |
| ACM Drilling Limited | Construction | 2024 |
| Acmarketing Ltd | Professional & scientific | 2025 |
| Acme Property Services Limited | Construction | 2024 |
| ACR Real Estate Ltd | Real estate | 2023 |
| Acreage Property Management Limited | Real estate | 2022 |
| ACS Consulting Limited | Administrative & support | 2014 |
| Actionworth Limited | Real estate | 1995 |
| Active Guard Security Services Limited | Administrative & support | 2016 |
| Active Resourcing Ltd | Professional & scientific | 2022 |
| Actus Construction Limited | Construction | 2020 |
| Acube Systems Limited | Information & communication | 2022 |
| Acuity H Ltd | Real estate | 2022 |
| ACW Property Limited | Construction | 2007 |
| ADA Agunwah Consultancy Limited | Health & social care | 2013 |
| ADA Mechanical Ltd | Construction | 2018 |
| Adam Brazier Photography Limited | Professional & scientific | 2020 |
| Adam RAE Brook Limited | Construction | 2022 |
| Adamally Limited | Health & social care | 2018 |
| Adams Property Partnership Limited | Real estate | 2017 |
| Adbs Construction Ltd | Construction | 2018 |
| ADC Dance & Events Limited | Education | 2025 |
| ADC London Limited | Wholesale & retail | 2015 |
| Addictive Behaviour Limited | Information & communication | 2012 |
| ADE Consultancy Ltd | Administrative & support | 2025 |
| Adela & Matteo Ltd | Construction | 2025 |
| Adera Capital Ltd | Professional & scientific | 2025 |