| A P Electronics Limited | Wholesale & retail | 2004 |
| A P George & SON Limited | Construction | 2005 |
| A R Benson (Rochford) Limited | Professional & scientific | 1993 |
| A Reeves Electrical Contractors Limited | Construction | 2007 |
| A Sense of Wonder Ltd | Education | 2007 |
| A Smith (Golf) Limited | Hospitality | 1991 |
| A Star Quality Group Ltd | Manufacturing | 2017 |
| A Star Vapes Ltd | Other services | 2017 |
| A Staunton Groundwork and Civil Engineering Limited | Other services | 2006 |
| A&R Mobile Accessories Ltd | Wholesale & retail | 2020 |
| A&R Portfolio Properties Ltd | Real estate | 2026 |
| A&Za Enterprises Ltd | Wholesale & retail | 2025 |
| A. & E. Connock (Perfumery & Cosmetics) Limited | Manufacturing | 1975 |
| A. & L. Stores Limited | Real estate | 2002 |
| A. Ashton Limited | Manufacturing | 2003 |
| A. J. Watson (Construction) Limited | Construction | 2007 |
| A.A. Floor Services Limited | Construction | 1992 |
| A.C. Fixings Limited | Wholesale & retail | 1999 |
| A.C. Pumps Limited | Wholesale & retail | 1993 |
| A.C.L. Security Limited | Administrative & support | 2002 |
| A.D. Fuel Oils Limited | Wholesale & retail | 1983 |
| A.D. Griffiths and Associates Limited | | 1984 |
| A.D.Lintern(Assessors)Limited | | 1964 |
| A.D.M. Scaffolding Limited | | 1992 |
| A.E. Batchelor & SON (Epping) Limited | Manufacturing | 1946 |
| A.E. Malcolm Ltd | Education | 2022 |
| A.G. Butler & SON Limited | Extraterritorial | 1972 |
| A.G.E. Nursing Homes Limited | Health & social care | 1990 |
| A.I. Cohen & Associates Limited | Professional & scientific | 2002 |
| A.J. Lowe Limited | Information & communication | 1987 |
| A.J.Dyke & SON Limited | Professional & scientific | 1973 |
| A.J.S. Manufacturing Limited | Manufacturing | 2000 |
| A.K. Collins (Construction) Limited | Wholesale & retail | 1990 |
| A.M. Robinson Limited | Professional & scientific | 2006 |
| A.Moss (Electrical & Mechanical Services) Limited | Manufacturing | 1997 |
| A.N. Distribution Limited | Transport & logistics | 1997 |
| A.P.G. Enterprises Limited | Water & waste | 2002 |
| A.R. Paper Converters Ltd | Manufacturing | 1987 |
| A.R.Adams (Funeral Directors) Limited | Other services | 1950 |
| A.R.J. Sansom Limited | Wholesale & retail | 2002 |
| A.S. Electrical Limited | Construction | 2005 |
| A.S. Greenstreet Limited | Professional & scientific | 2003 |
| A.S.A. Services Limited | Information & communication | 1994 |
| A.Smith & Sons (Building) Limited | Construction | 1991 |
| A.T.B. Enterprises (UK) Limited | | 2005 |
| A.V. Hurst & Sons (Fobbing) Limited | Real estate | 1975 |
| A1 (Himfens) Alarms Limited | Construction | 2004 |
| A1 Sailing Ltd | Arts & recreation | 2002 |
| A1 Wasps & Bees Ltd | Real estate | 2003 |
| A2CLOUD Solutions Ltd | Information & communication | 2022 |
| A3 Health Solutions Ltd | Health & social care | 2024 |
| AA Wholesalers Ltd | Wholesale & retail | 2022 |
| Aa&G Properties LLP | | 2022 |
| Aahh Property Investment Ltd | Real estate | 2024 |
| AAI Business Solutions UK Limited | Transport & logistics | 2017 |
| AAK Associates Limited | Manufacturing | 2020 |
| Aalyar Commerce Limited | Wholesale & retail | 2025 |
| Aamir Nazeer Limited | Wholesale & retail | 2026 |
| Aanas Enterprise Ltd | Wholesale & retail | 2025 |
| AAR KAY F.L. (London) Limited | Wholesale & retail | 2007 |
| Aark Building Design Limited | Construction | 2003 |
| Aark Homes Ltd | Administrative & support | 2016 |
| Aaron Flooring Services Ltd | Construction | 2003 |
| Aasia Hussain Ltd | Wholesale & retail | 2022 |
| Aathmi Ltd | Wholesale & retail | 2026 |
| Aazu Ltd | Wholesale & retail | 2026 |
| AB Freelance Ltd | Professional & scientific | 2019 |
| Abacus Accountancy & Business Services Limited | Administrative & support | 1993 |
| Abacus Financial & Mortgage Services Limited | Financial services | 1998 |
| Abacus Franchise Limited | Professional & scientific | 2006 |
| Abacus Internet Ltd | Extraterritorial | 1996 |
| Abacus NET Limited | Professional & scientific | 1997 |
| Abacus Property Services (U.K.) Ltd. | Real estate | 1995 |
| Aban Medicals Limited | Health & social care | 2024 |
| Abbey & Jackson Ltd | Real estate | 2025 |
| Abbey Care Centre Limited | Health & social care | 2006 |
| Abbey Care Complex Limited | Health & social care | 2003 |
| Abbey Carpets (Essex) Limited | Wholesale & retail | 2003 |
| Abbey Cars (Chertsey) Limited | Transport & logistics | 2003 |
| Abbey Cheam Centre Ltd | Health & social care | 2004 |
| Abbey Ravenscroft Park Limited | Health & social care | 2005 |
| Abbey Service Station Limited | Wholesale & retail | 1970 |
| Abbey Total Care Group Limited | Professional & scientific | 2003 |
| Abbey Wood Traders Limited | Wholesale & retail | 2005 |
| Abbeyaro Ltd | Hospitality | 2018 |
| Abbeyfield Canvey Island Society Limited(The) | Health & social care | 1959 |
| Abbeyom Builders Limited | | 1988 |
| Abbeyway Contracts Limited | Professional & scientific | 1996 |
| Abbott and SON Ltd | Construction | 2022 |
| Abbott Sale Limited | Wholesale & retail | 2025 |
| ABC Bar & Kitchen Equipment Limited | Professional & scientific | 2005 |
| ABC123 Accounting Services Limited | Professional & scientific | 2002 |
| ABD Engineering & Development Ltd | Wholesale & retail | 2025 |
| Abdul Hanan Ecom & Co Limited | Wholesale & retail | 2026 |
| Abel & Co Accountants Limited | Professional & scientific | 2006 |
| Abercorn Plant & Garden Centre Limited | Wholesale & retail | 2007 |
| Aberdour Accountancy Services Ltd | Professional & scientific | 1998 |
| Abershourne Limited | Wholesale & retail | 1976 |
| Abesongs Limited | Arts & recreation | 1975 |
| ABI & Abiz Ltd | Real estate | 2024 |