| A. Linen Depot Ltd | Hospitality | 2020 |
| A.C.L. Locksmiths Limited | Other services | 2002 |
| A.Events Hire Ltd | Hospitality | 2020 |
| A.F. Holmes (Eaton Bray) Limited | Agriculture & fishing | 1966 |
| A.F.B Ltd | Construction | 2022 |
| A.J. Willson (Properties) Limited | Construction | 1963 |
| A.S.A.P. Painting & Decorating Contractors Ltd | Construction | 2018 |
| A.S.Cars (UK) Ltd | Wholesale & retail | 2009 |
| A.S.H Air Conditioning Solutions Ltd. | Professional & scientific | 2022 |
| A.W. Richards Consulting Limited | Administrative & support | 2012 |
| A.White Martinez Plumbing & Heating Limited | Construction | 2018 |
| A1RAJ Catering Suppliers Limited | Wholesale & retail | 2019 |
| A2S Property Management Limited | Real estate | 2024 |
| A5 Autobody Limited | Wholesale & retail | 2017 |
| A5 Cars Point Limited | Wholesale & retail | 2025 |
| A5 Electrical Wholesalers Ltd | Wholesale & retail | 2021 |
| A5 Food & Wine Limited | Wholesale & retail | 2016 |
| A5 Garage Limited | Other services | 2017 |
| AA ALI Barber Ltd | Other services | 2024 |
| AA Food S END Ltd | Hospitality | 2025 |
| AA Power FIX Ltd | Construction | 2021 |
| AA Shipping Limited | Transport & logistics | 2025 |
| AA Star Construction Limited | Construction | 2021 |
| Aa+Rac Associates Ltd. | Wholesale & retail | 2004 |
| AAA Express Limited | Hospitality | 2020 |
| AAA Hatwar Limited | Health & social care | 2011 |
| AAA Wholesale & Importers Limited | Manufacturing | 2009 |
| Aaag Studios Ltd | Information & communication | 2025 |
| AAC UK Business Limited | Transport & logistics | 2020 |
| AAG Construction Ltd | Construction | 2014 |
| Aarathi Ltd | Wholesale & retail | 2026 |
| Aaron Powell Consultancy Services Limited | Professional & scientific | 2012 |
| Aaru UK Ltd | Wholesale & retail | 2020 |
| AB Family Limited | Real estate | 2025 |
| AB Printing Ltd | Administrative & support | 2010 |
| Abacus Development UK Limited | Information & communication | 2007 |
| Abarth Construction Ltd | Construction | 2022 |
| Abba Consultancies Ltd | Other services | 2024 |
| Abbey Electrical Contractors Limited | Construction | 2002 |
| Abbey Refrigerated Transport Ltd | Transport & logistics | 2003 |
| Abbots Spice Limited | Hospitality | 2021 |
| Abbottpak Ltd | Transport & logistics | 2025 |
| ABC Hospitality Limited | Administrative & support | 2019 |
| ABC Winfield RTM Company Limited | Households | 2008 |
| Abedd Nann ITD Ltd | Education | 2026 |
| Abel Personnel Limited | Administrative & support | 2025 |
| Abenson Limited | Health & social care | 2019 |
| Abetterlife-Uk Ltd | Other services | 2005 |
| Abeyrin Total Wellness Ltd | Health & social care | 2023 |
| Abe’S Beauty Emporium Ltd | Wholesale & retail | 2025 |
| ABI & SON UK Limited | Real estate | 2023 |
| Abileo Group Ltd | Construction | 2022 |
| Abington Limited | Hospitality | 2025 |
| Abiud Ltd | Transport & logistics | 2021 |
| ABL Design and Build Ltd | Professional & scientific | 2020 |
| Able (Solar) Ltd | Construction | 2022 |
| Able Maintenance Services Limited | Construction | 2005 |
| Abns Associates Limited | Administrative & support | 2011 |
| Abra Technologies Limited | Information & communication | 2023 |
| Absalom and Luff Heating Solutions Ltd | Construction | 2014 |
| Abuawwad Ltd | Wholesale & retail | 2026 |
| Abundance Consultants Limited | Professional & scientific | 2013 |
| ABZ Enterprise Limited | Transport & logistics | 2019 |
| AC Asset Management Ltd | Real estate | 2022 |
| Aca-Apex Limited | Manufacturing | 2000 |
| Acarres Ltd | Health & social care | 2023 |
| ACC Detailing Limited | Transport & logistics | 2022 |
| Accident Assist Network Ltd | Professional & scientific | 2025 |
| Accountancy & Tax Solutions (UK) Ltd | Professional & scientific | 2022 |
| Accountants’ Growth Club Ltd | Professional & scientific | 2010 |
| Accounting a+ Ltd | Professional & scientific | 2025 |
| Accounts - Tax Ltd | Professional & scientific | 2013 |
| Accurate Constructions London Ltd | Construction | 2026 |
| Ace Alliance Limited | Real estate | 2022 |
| Ace Desserts Limited | Hospitality | 2020 |
| Ace of Space Property Management Services Ltd | Real estate | 2016 |
| Achievers Care Services Limited | Health & social care | 2024 |
| Achievers Recruitment Ltd | Administrative & support | 2022 |
| Acorn Dallow Road Limited | Wholesale & retail | 2018 |
| Acorn Property Specialists Limited | Real estate | 2014 |
| Acorns Projects Limited | Construction | 2005 |
| Acrovision Trustee Company Limited | Administrative & support | 2020 |
| ACS Design Consultancy Limited | Professional & scientific | 2023 |
| Action Recruiters Limited | Administrative & support | 2022 |
| Activ People Group Limited | Professional & scientific | 2025 |
| Active Creative Limited | Arts & recreation | 2007 |
| Active Environmental Management Limited | Water & waste | 2014 |
| Active Environmental Services Limited | Administrative & support | 1999 |
| Active Flow Limited | Wholesale & retail | 2025 |
| Active Homecare Ltd | Health & social care | 2018 |
| Acton Electrical Ltd | Construction | 2025 |
| Acupuncture Healthcare Limited | Health & social care | 2025 |
| Adam Baksh MAN Ltd | Wholesale & retail | 2018 |
| Adam Gray Limited | Other services | 2004 |
| Adam Reid Coaching Limited | Health & social care | 2021 |
| Adams Tree & Gardening Services Ltd | Administrative & support | 2025 |
| ADB Transport & Logistics Ltd | Transport & logistics | 2022 |
| Adda Group Ltd | Real estate | 2023 |
| Address Construction Limited | Construction | 2026 |
| Adela Driving School Ltd | Education | 2024 |