| A & E Professional Services Ltd | Health & social care | 2024 |
| A & H Associates LLP | | 2001 |
| A & M Construction Engineers Ltd | Construction | 2018 |
| A & S MOT Limited | Wholesale & retail | 2020 |
| A & T Stay Limited | Real estate | 2025 |
| A Binns Electrical Ltd | Construction | 2014 |
| A C T X Limited | Other services | 2006 |
| A C Vinter Enterprises Limited | Administrative & support | 2005 |
| A C Vinter Management Ltd | Real estate | 2005 |
| A C Vinter Properties Limited | Real estate | 2015 |
| A Conroy Building & Development Ltd | Construction | 2014 |
| A D Contracts Limited | Construction | 1998 |
| A E M Demolition Limited | Construction | 2006 |
| A Everitt Limited | Professional & scientific | 2013 |
| A F Build Services Ltd | Administrative & support | 2018 |
| A Goodman Services Limited | Professional & scientific | 2026 |
| A Jennings Carpentry Limited | Manufacturing | 2023 |
| A Lockwood Limited | Administrative & support | 2013 |
| A Purple Vision Limited | Arts & recreation | 2000 |
| A Quantrill Ltd | Professional & scientific | 2025 |
| A R Wand Sprinklers Limited | Construction | 2012 |
| A Room 4U Ltd | Households | 2021 |
| A S Graphic Design Limited | Professional & scientific | 2017 |
| A Siddiqui Consultancy Limited | Health & social care | 2019 |
| A Squared Studio Ltd | Professional & scientific | 2006 |
| A Star Lofts & Extensions Ltd | Construction | 2018 |
| A T S Signs Limited | Manufacturing | 2006 |
| A Tribe Called PT Ltd | Education | 2020 |
| A Webster Design Limited | Professional & scientific | 2019 |
| A&B Holdings Ltd | Real estate | 2023 |
| A&E Pharma Ltd | Wholesale & retail | 2025 |
| A. Figg Builders Limited | Construction | 2003 |
| A. J. Williams Insulation Limited | Construction | 2007 |
| A. W. Gloyne Enterprises Limited | Hospitality | 1991 |
| A. W. Gloyne Limited | Administrative & support | 1986 |
| A.A Wait Painters Ltd | Construction | 2025 |
| A.A.A. Bathroom Supplies & Installations Ltd | Construction | 2011 |
| A.B.N. Maintenance Limited | Other services | 2004 |
| A.C. Harris Limited | Administrative & support | 2002 |
| A.E.Hobbs,Limited | Wholesale & retail | 1919 |
| A.E.M Trading Limited | Other services | 2006 |
| A.J. Bush Limited | Real estate | 1981 |
| A.L Detailing & Maintenance Ltd | Administrative & support | 2024 |
| A.L.Rinstallationservices Ltd | Construction | 2024 |
| A.M. Wynter Xpress Limited | Other services | 2009 |
| A.M.A. Austin Investments Limited | Professional & scientific | 1987 |
| A.R. Beckford Trading Limited | Other services | 2007 |
| A1ST UK Limited | Construction | 2025 |
| A2 Electrical Ltd | Construction | 2004 |
| A7UK Ltd | Wholesale & retail | 2018 |
| AA Designworks Ltd | Professional & scientific | 2016 |
| AA Process Limited | Real estate | 2018 |
| AAA Services (Essex) Limited | Construction | 2005 |
| Aaid Ltd | Professional & scientific | 2015 |
| AAN Property Developments Limited | Real estate | 2024 |
| Aarohan Investments Ltd | Financial services | 2022 |
| Aaron Paving (Essex) Limited | Construction | 2013 |
| Aarrkk LLP | | 2009 |
| AAU Contractors Ltd | Construction | 2018 |
| Abaco Island Properties Ltd | Real estate | 2019 |
| Abacus Estates (Kensal Rise) Limited | Real estate | 2011 |
| Abbey Construction Southend Limited | Construction | 2001 |
| Abbott Smart Storage Solutions Ltd | Manufacturing | 2025 |
| ABE Carpentry Ltd | Construction | 2019 |
| Abexie Limited | Manufacturing | 2008 |
| ABG Architecture Ltd | Professional & scientific | 2011 |
| ABI Mills Limited | Health & social care | 2025 |
| Abkg Trading Limited | Wholesale & retail | 2024 |
| ABP Administration and Marketing Dynamics Ltd | Administrative & support | 2011 |
| Abpremiumdesigns Ltd | Real estate | 2023 |
| Absent Friends Limited | Information & communication | 2026 |
| Absolute Assets and Investments Limited | Real estate | 2018 |
| Absolute Maintenance South East Limited | Construction | 2021 |
| Absolute Photography Limited | Professional & scientific | 2006 |
| Absolute Repairs Limited | Administrative & support | 2007 |
| AC Accountancy Group Limited | Professional & scientific | 2024 |
| AC Health and Nutrition Limited | Health & social care | 2005 |
| AC Rowley Limited | Financial services | 2025 |
| Academy Square Developments Limited | Real estate | 2010 |
| Accountancy Crunch Ltd | Administrative & support | 2022 |
| Ace Demolition Services Limited | Administrative & support | 2010 |
| Ace Services Group Limited | Construction | 2023 |
| Acebuche Administration Limited | Professional & scientific | 2016 |
| Acer Partnership Consulting Engineers Limited | Professional & scientific | 2005 |
| Acers and Cole Electrical Ltd | Construction | 2022 |
| Achmore Ltd | Real estate | 2007 |
| ACL Brickwork Limited | Administrative & support | 2014 |
| ACL Graphic Installations Ltd | Professional & scientific | 2015 |
| Acme Asset Management Limited | Real estate | 2018 |
| Acorn Contracting Ltd | Construction | 2024 |
| Acorn Fencing & Landscapes Limited | Administrative & support | 2020 |
| Acorn Print (Southend) Ltd | Manufacturing | 2006 |
| Acorn Tree Investments Limited | Administrative & support | 2024 |
| Acoustic Engineering Services Limited | Professional & scientific | 1976 |
| Acquisition Tutoring Services Limited | Education | 2020 |
| Acre Management Limited | Real estate | 2021 |
| ACS Automotive Recruitment Consultancy Limited | Administrative & support | 2012 |
| Action for Living Limited | Education | 2012 |
| Active Academy Southend Limited | Health & social care | 2025 |
| Active Care U.K. Ltd | Professional & scientific | 2004 |