| &Lloyd Ltd | Professional & scientific | 2023 |
| 01000654 Limited | Extraterritorial | 1971 |
| 124 Packington Street Limited | Real estate | 2011 |
| 14 Willoughby Road (Freehold) Limited | Households | 2019 |
| 142 Art CIC | Wholesale & retail | 2020 |
| 1812 Holdings Ltd | Financial services | 2025 |
| 1BLACK Ltd | Administrative & support | 2024 |
| 1UP Gaming Limited | Wholesale & retail | 2015 |
| 3 Retro Ltd | Wholesale & retail | 2016 |
| 414 Kiting Ltd | Arts & recreation | 2018 |
| 48 Northfield Road Management Limited | Households | 1985 |
| 4T Limited | Health & social care | 2020 |
| 52 Red Lion Street (Freehold) Limited | Households | 2019 |
| 68 Auto Performance Limited | Professional & scientific | 2011 |
| 8 Skylarks Ltd | Professional & scientific | 2022 |
| 80 Christchurch ST Management Limited | Real estate | 2006 |
| 90 Hillfield Road London NW6 Limited | Real estate | 1996 |
| A & L UK Properties Ltd | Real estate | 2020 |
| A & S Props Ltd | Real estate | 2024 |
| A C Mutimer Ltd | Wholesale & retail | 2003 |
| A D H Creative Limited | Other services | 2005 |
| A J Sargent Electrical Solutions Limited | Construction | 2016 |
| A P Clarke Developments Ltd | Real estate | 2022 |
| A P Clarke Holdings Ltd | Administrative & support | 2023 |
| A P Clarke Ltd | Construction | 2002 |
| A P N Pinfold & Co Limited | Professional & scientific | 1996 |
| A Passion for Seafood Ltd | Agriculture & fishing | 2005 |
| A R Smart Systems Ltd | Administrative & support | 2018 |
| A&J Events and Promotions Limited | Arts & recreation | 2026 |
| A&K Forestry and Nature Ltd | Agriculture & fishing | 2023 |
| A.G.Potter (Framlingham) Limited | Administrative & support | 1928 |
| A.W. Mortier (Farms) Limited | Agriculture & fishing | 1964 |
| A1 Pressure Washers Limited | Wholesale & retail | 2002 |
| Aardvarks & Dragons Limited | Wholesale & retail | 2020 |
| Aarnat's Ltd | Wholesale & retail | 2019 |
| Aaron Electrical (Suffolk) Ltd | Construction | 2019 |
| Aaron Nobbs Electrical Ltd | Construction | 2008 |
| Abersoch Offaxis Limited | Wholesale & retail | 2014 |
| Abode Alliance Limited | Real estate | 2024 |
| Abode Retreats Limited | Real estate | 2025 |
| Abrehart Ecology Limited | Professional & scientific | 2016 |
| Ac-Uk Holding Ltd | Administrative & support | 2024 |
| ACC Art Books Limited | Information & communication | 2015 |
| ACC Arts Bibliographic Limited | Wholesale & retail | 2023 |
| ACC Book Distribution Limited | Information & communication | 2015 |
| ACC Consulting Ltd. | Professional & scientific | 2005 |
| ACC Publishing Group Limited | Professional & scientific | 1991 |
| Access Ability Platforms Limited | Construction | 1995 |
| Ace Paving (Suffolk) Limited | Administrative & support | 2007 |
| Ace Systemics Ltd | Wholesale & retail | 2026 |
| Achour Investments Limited | Financial services | 2024 |
| Achresis Arts Limited | Arts & recreation | 2026 |
| Acorns 4 Kids Ltd | Education | 2022 |
| Acoustic Principles Limited | Professional & scientific | 2018 |
| ACR Cars Ltd | Administrative & support | 2022 |
| Acre Enterprises (ARW) Limited | Manufacturing | 2024 |
| Active Cloud Solutions Limited | Information & communication | 2009 |
| Activities 4 ALL Limited | Real estate | 2004 |
| AD LIB Publishers Limited | Information & communication | 2019 |
| Adapt Law Limited | Administrative & support | 2018 |
| Addison Electrical (Suffolk) Limited | Construction | 2012 |
| Additions Logistics Ltd | Administrative & support | 2024 |
| Ademptor Consulting Limited | Other services | 2013 |
| ADG Property Management & Investments Ltd | Real estate | 2024 |
| ADL Consultants Limited | Professional & scientific | 2012 |
| ADM Ventures and Investments Limited | Real estate | 2000 |
| Adrian Green Photography Limited | Professional & scientific | 2007 |
| Adrian Hammond Ltd | Construction | 2002 |
| Adrian Howells Consulting Ltd | Professional & scientific | 2025 |
| Adventures in Content Ltd | Administrative & support | 2014 |
| AER Data and Technical Services Ltd | Professional & scientific | 2026 |
| African Safari Experience Limited | Administrative & support | 2016 |
| AG Infra Limited | Real estate | 2020 |
| Agies Limited | Hospitality | 1996 |
| Agri Procurement Alliance Limited | Administrative & support | 2023 |
| Agri-Gen Limited | Energy | 2008 |
| Agrifly Limited | Agriculture & fishing | 2014 |
| Agriforce Recycling Limited | Water & waste | 2016 |
| Airfield Farm Limited | Agriculture & fishing | 2019 |
| Airfield Holdings Limited | Financial services | 2021 |
| Aisha's Catering Ltd | Hospitality | 2026 |
| AJF Consulting Limited | Information & communication | 2019 |
| Albany Health Limited | Health & social care | 1999 |
| Albany Travel (Ipswich) Limited | Transport & logistics | 2003 |
| Albert Brent Limited | Health & social care | 2009 |
| Alde Interiors Limited | Professional & scientific | 2024 |
| Aldeburgh Vets Ltd | Professional & scientific | 2020 |
| Aldis & MAY Ltd | Construction | 2018 |
| Alej Limited | Information & communication | 2007 |
| Alex Pearson Productions Limited | Arts & recreation | 2017 |
| Alexandria COE Ltd | Arts & recreation | 2020 |
| Alia Ventures Ltd | Professional & scientific | 2020 |
| ALL Saints Schools Trust | Education | 2018 |
| Allbay Ltd | Wholesale & retail | 2002 |
| Allfarm Installations Limited | Manufacturing | 1998 |
| Allglass (Anglia) Limited | Construction | 1991 |
| Allied Consultancy Services Limited | Professional & scientific | 2020 |
| Alpha Fumigation Services Limited | Administrative & support | 2011 |
| Alterra Developments Limited | Construction | 2019 |
| Alterra Farms Limited | Agriculture & fishing | 2011 |