| Aesthetic Interior Cleaning Services Ltd | Administrative & support | 2024 |
| Aesthetica Clinic Limited | Other services | 2014 |
| Aesthetics Building & Maintenance Ltd | Construction | 2023 |
| Aetehnology Ltd | Wholesale & retail | 2024 |
| AFA Lettings Limited | Real estate | 2002 |
| AFC Franchising Ltd | Hospitality | 2026 |
| AFC Pogmoor Ltd | Arts & recreation | 2019 |
| Affable CIC | Administrative & support | 2025 |
| Affecto Recruitment Ltd | Administrative & support | 2013 |
| Affiliate Solutions Limited | Information & communication | 2004 |
| Affinity Edge City Living Limited | Real estate | 2022 |
| Affinity Operations Limited | Professional & scientific | 2024 |
| Affirm Diagnostics Ltd | Health & social care | 2026 |
| Afordable Fuel Solutions Ltd | Construction | 2024 |
| AFP Medics Ltd | Health & social care | 2024 |
| Afridi Tech Ltd | Manufacturing | 2024 |
| After Every Workout Limited | Wholesale & retail | 2025 |
| Aftercare Holdings Limited | Construction | 2023 |
| Against the Grain One Stop Gluten-Free Shop Limited | Wholesale & retail | 2025 |
| AGB Properties Ltd | Real estate | 2021 |
| AGD Rail Traction Engineering Services Ltd | Professional & scientific | 2017 |
| AGE UK Barnsley | Health & social care | 2011 |
| AGE UK Barnsley (Trading) Limited | Extraterritorial | 1994 |
| Ageless Alchemist Ltd | Manufacturing | 2025 |
| Agency Acquisitions Limited | Professional & scientific | 1993 |
| Agency by Agency Limited | Administrative & support | 2025 |
| Agentgold Limited | Households | 1987 |
| Agentic Automation Ltd | Information & communication | 2025 |
| Agg-Pak Holdings Limited | Financial services | 2021 |
| Aggrotech UK Limited | Wholesale & retail | 2018 |
| Agnes Educational Enterprises Limited | Health & social care | 1994 |
| AGO Property Limited | Real estate | 2025 |
| Agqs Limited | Construction | 2011 |
| AGR Glass Holdings Limited | Financial services | 2023 |
| AGS Distribution Limited | Wholesale & retail | 2025 |
| Agus Properties Limited | Real estate | 2023 |
| AH Yates Limited | Financial services | 2023 |
| AI Gurus Group Ltd | Information & communication | 2025 |
| AI Leasing Limited | Administrative & support | 2022 |
| Aidans Automobiles Limited | Wholesale & retail | 2017 |
| Aiden LEE Contracting Ltd | Transport & logistics | 2026 |
| Air Information Systems Limited | Information & communication | 2025 |
| Air Source Heat and Power Ltd | Wholesale & retail | 2014 |
| Airspace Assets LLP | | 2014 |
| AJ & Sons Property Ltd | Real estate | 2025 |
| AJ Chauffeuring Limited | Transport & logistics | 2018 |
| AJ Remedials & Groundworks Ltd | Construction | 2025 |
| AJ Wardrobes Ltd | Construction | 2025 |
| Aj.Riggott Property Limited | Real estate | 2025 |
| AJ7 Developments Ltd | Real estate | 2022 |
| AJA Total Consulting Limited | Professional & scientific | 2024 |
| AJB Care Limited | Health & social care | 2004 |
| Ajbbs Limited | Construction | 2017 |
| Ajem Enterprises Limited | Financial services | 2017 |
| AJH Autos Ltd | Wholesale & retail | 2018 |
| AJH Site Services Limited | Construction | 2025 |
| AJM Accounting Ltd | Professional & scientific | 2026 |
| AJM Power Transmission Supplies Ltd | Administrative & support | 2020 |
| AJM Services (UK) Limited | Households | 2014 |
| AJM Words Limited | Information & communication | 2011 |
| AJP Project Solutions Ltd | Professional & scientific | 2023 |
| AJR Motor Company Ltd | Wholesale & retail | 2020 |
| AJR Transportation Limited | Transport & logistics | 2015 |
| AJS Restoration Services Ltd | Construction | 2025 |
| AJS Travel Services Limited | Transport & logistics | 2025 |
| AJT Flat Roofing Limited | Construction | 2025 |
| AJT Installs Ltd | Wholesale & retail | 2021 |
| AJW Vehicle Fittings Limited | Wholesale & retail | 2017 |
| Aj’S Premium Autos Ltd | Wholesale & retail | 2026 |
| AK Ceramics Ltd | Construction | 2025 |
| Akld Training Limited | Education | 2017 |
| Aksu Transport Ltd | Transport & logistics | 2025 |
| AKW Operator Hire Limited | Construction | 2025 |
| AL & Di's Limited | Wholesale & retail | 2014 |
| AL Control Solutions Ltd | Construction | 2014 |
| Al'Igator Signs Ltd | Real estate | 2003 |
| Aladine Limited | Health & social care | 2016 |
| Alan Wood (Plumbing & Heating Contractors) Limited | Construction | 1998 |
| Albert Street Car Park Limited | Other services | 2020 |
| Albert's Estate Ltd | Real estate | 2015 |
| Albion Developments & Investments Limited | Construction | 2003 |
| Albion Distribution Limited | Extraterritorial | 2007 |
| Albion Gashi Limited | Real estate | 2026 |
| Albion Valves & Controls Limited | Extraterritorial | 2007 |
| Albion Valves (Europe) Limited | Extraterritorial | 2021 |
| Albion Valves (Group) Limited | Extraterritorial | 2021 |
| Albion Valves (Holdings) Limited | Extraterritorial | 2021 |
| Albion Valves (International) Limited | Wholesale & retail | 2018 |
| Albion Valves (UK) Limited | Wholesale & retail | 1995 |
| Albion Valves Limited | Extraterritorial | 2019 |
| Alchemi Professional Solutions Limited | Wholesale & retail | 2024 |
| Alcmy Limited | Information & communication | 2023 |
| Aldham Mill Limited | Agriculture & fishing | 2023 |
| Aldham Takeway Ltd | Hospitality | 2026 |
| Aleksandr Ltd | Construction | 2023 |
| Alesiador Ltd | Transport & logistics | 2025 |
| Alex Cesarsky Architects Ltd | Professional & scientific | 2018 |
| Alex POL Trans Limited | Wholesale & retail | 2015 |
| Alex Taxi Ltd | Construction | 2018 |
| ALEX29 Ltd | Transport & logistics | 2024 |