| A & D Motors Services and Repairs Ltd | Wholesale & retail | 2023 |
| A & D Swimming Pools Limited | Construction | 2005 |
| A & H Property Investment (UK) Ltd | Households | 2019 |
| A & K Tyres & Spares Limited | Wholesale & retail | 2002 |
| A & M GAS and Plumbing Services Limited | Wholesale & retail | 2003 |
| A & O Logistics Limited | Professional & scientific | 2002 |
| A & P Financial Services Ltd | Administrative & support | 2004 |
| A C a Distribution Limited | Wholesale & retail | 1996 |
| A J Electrical Contractors Limited | Construction | 2007 |
| A J R Audio Limited | Information & communication | 2006 |
| A K Roofing & Guttering Limited | Construction | 2003 |
| A New Solution Limited | Information & communication | 2005 |
| A O B (UK) Limited | Real estate | 1999 |
| A P a Planning Services Limited | Professional & scientific | 1998 |
| A P Garage Services Limited | Professional & scientific | 2003 |
| A Ridgley Landscape Gardener | | 1998 |
| A S a Estates Limited | Real estate | 1997 |
| A S Brickwork Limited | Construction | 2006 |
| A S F L Limited | Professional & scientific | 2004 |
| A S Taxation Limited | Professional & scientific | 2005 |
| A Styling Story Ltd | Other services | 1992 |
| A&A UKP Holdings Ltd | Real estate | 2018 |
| A&R Convenience Store Limited | Wholesale & retail | 2019 |
| A&S Financial Services Ltd | Financial services | 2013 |
| A-Level Software Limited | Information & communication | 1996 |
| A. Dennison & Co. Limited | Administrative & support | 2002 |
| A. G. B. Contractors Limited | Construction | 2002 |
| A. Smith (Memorials) Limited | Other services | 2003 |
| A. Welcome House Limited | Health & social care | 1991 |
| A.C.Winter(Builders)Limited | Real estate | 1952 |
| A.D.S Estate Management Ltd | Real estate | 2020 |
| A.G.D. Properties Limited | Real estate | 2001 |
| A.H.Rackham Limited | Wholesale & retail | 1959 |
| A.J.F. Consultants Limited | Real estate | 1988 |
| A.L.O.B. Limited | Wholesale & retail | 2005 |
| A.M.S. Management (UK) Limited | Real estate | 2000 |
| A.N.J. Coowar Limited | Health & social care | 2000 |
| A.N.T Security Fencing Ltd | Administrative & support | 2025 |
| A.R. Gunner Limited | Construction | 1997 |
| A.S. Ashcroft Limited | Construction | 1989 |
| A.S. Chowler Limited | | 1976 |
| A.Smith(Southwark)Limited | Other services | 1955 |
| A.V.B. (Hillhead) Limited | Real estate | 1974 |
| A.W.Harman Limited | Wholesale & retail | 1959 |
| A.Wise Chemists Limited | Real estate | 1972 |
| A1 Cabco United Regency Limited | Transport & logistics | 2005 |
| A1 Home Services Ltd | Manufacturing | 2003 |
| A1A Building & Roofing Services Ltd | Construction | 2016 |
| A21 Executive Ltd | Transport & logistics | 2025 |
| A24 Group Limited | Administrative & support | 1996 |
| AA MAC Limited | Information & communication | 2002 |
| AA United Ltd | Wholesale & retail | 2017 |
| AAA Consultancy Limited | Professional & scientific | 1990 |
| AAA Credit Hire Ltd | Administrative & support | 2019 |
| AAA Employment Limited | Professional & scientific | 1988 |
| AAA Interim Management Limited | Professional & scientific | 1990 |
| AAA Property Holding Ltd | Real estate | 2018 |
| Aable Electrical Limited | Construction | 2001 |
| Aadeva Limited | Professional & scientific | 2002 |
| AAK Healthcare Services Ltd | Administrative & support | 2018 |
| Aaniyah Enterprises Ltd | Wholesale & retail | 2023 |
| Aarad Ltd | Wholesale & retail | 2023 |
| Aardvark Research Limited | Professional & scientific | 2007 |
| Aarin Consulting Ltd | Information & communication | 2003 |
| Aaryan Prema Co. Ltd | Wholesale & retail | 2025 |
| Aask International Limited | Real estate | 1997 |
| AB Bensham Ltd | Extraterritorial | 2021 |
| AB Electronic Assemblies Limited | Professional & scientific | 1982 |
| AB Miles Limited | Information & communication | 2002 |
| AB Projects (UK) Limited | Construction | 2015 |
| Abacairn Limited | Construction | 2006 |
| Abacus Business Strategies Limited | Professional & scientific | 2002 |
| Abacus Management Services Limited | Real estate | 1997 |
| Abature Ltd | Professional & scientific | 2006 |
| Abbey Court (Camberley) Ltd. | Households | 2009 |
| Abbey Estates (UK) Ltd | Real estate | 2005 |
| Abbey Sealants Limited | Construction | 2008 |
| Abbey Worldwide Finance Limited | Financial services | 2016 |
| Abbeylands (Weybridge) Residents Association Limited | Real estate | 1969 |
| Abbots Groundworks Limited | Professional & scientific | 2003 |
| Abbotsford Care Limited | Extraterritorial | 2006 |
| Abbotsford Residents Association Limited | Real estate | 2005 |
| Abbotts Contract Cleaning Services Ltd | Administrative & support | 2007 |
| Abbusys Limited | Information & communication | 2004 |
| ABC Day Nurseries Limited | Education | 2005 |
| ABC Health and Safety Consultancy Limited | Professional & scientific | 2007 |
| ABI Exning Homes Ltd | Real estate | 2022 |
| Abib Developments Limited | Extraterritorial | 2019 |
| ABL Heating and Plumbing Supplies Limited | Wholesale & retail | 1984 |
| Able Waterproofing Limited | Construction | 1994 |
| Ablefeet Limited | Health & social care | 2004 |
| About Churn Limited | Information & communication | 1999 |
| About Solutions Limited | Information & communication | 2002 |
| About Time Theatre Company Limited | Arts & recreation | 1992 |
| Abraham and Sons Properties Ltd | Real estate | 2026 |
| Abros Associates Limited | Professional & scientific | 1992 |
| Abros Ltd | Professional & scientific | 2001 |
| Absolute Certainty Limited | Information & communication | 2001 |
| Absolute Curry Ltd | Hospitality | 2019 |
| Absolute High Speed Limited | Information & communication | 2002 |