| A-Ffinity Europe Ltd | Professional & scientific | 2015 |
| A.R. Mufti Limited | Information & communication | 2014 |
| A.Roe Pharma Consulting Limited | Professional & scientific | 2019 |
| AA360IP Services Limited | Professional & scientific | 2024 |
| AAH Slough Ltd | Wholesale & retail | 2025 |
| Aandp Media Ltd | Information & communication | 2013 |
| Abbas Tech Ltd | Professional & scientific | 2020 |
| Abilene Snowe Limited | Construction | 2010 |
| Ablehubb Workspace Ltd | Real estate | 2025 |
| Ablehubs Ltd | Real estate | 2026 |
| Abriand Bidco Limited | Financial services | 2022 |
| Abriand Freeholds Limited | Real estate | 2022 |
| Abriand Midco 1 Limited | Financial services | 2022 |
| Abriand Midco 2 Limited | Financial services | 2022 |
| Abriand Midco 3 Limited | Financial services | 2022 |
| Abriand Propco Limited | Real estate | 2022 |
| Abriand Topco Limited | Financial services | 2022 |
| Absolute Care Services (Richmond) Limited | Health & social care | 2013 |
| Absolute Care Services (Sutton) Limited | Health & social care | 2009 |
| Absolute Care Services Franchising Limited | Professional & scientific | 2007 |
| Absolute Care Services Ltd | Health & social care | 2002 |
| Absorption Ltd | Information & communication | 2022 |
| ACD Business Solutions Ltd | Information & communication | 2013 |
| Acme Graphics Limited | Manufacturing | 2003 |
| Acqui-Ventures Ltd | Wholesale & retail | 2021 |
| ACS Bookkeeping Services Ltd | Professional & scientific | 2017 |
| ACS Liberty Group Ltd | Information & communication | 2009 |
| ACS Liberty Group UK Ltd | Professional & scientific | 2015 |
| Action Graphics Ltd | Other services | 2010 |
| Active Movers Limited | Transport & logistics | 2007 |
| Adaret Limited | Other services | 2024 |
| ADASTRA99 Limited | Professional & scientific | 2025 |
| ADD & Abstract Productions Ltd | Information & communication | 2014 |
| Admiralty Way Apartments Limited | Households | 2004 |
| Advcy Ltd | Information & communication | 2025 |
| AF Property Management Limited | Real estate | 2008 |
| Affinity Nutrition Ltd | Hospitality | 2017 |
| Africa Alert Limited | Information & communication | 2014 |
| AGENCY55 Limited | Real estate | 2025 |
| AGS System Ltd | Agriculture & fishing | 2020 |
| AHA Hair &Beauty Academy Ltd | Other services | 2023 |
| Aimnell Limited | Information & communication | 2010 |
| Aintree Residents Company Limited | Administrative & support | 2012 |
| Airtear Ltd | Other services | 2017 |
| AJ & JAY Ltd | Real estate | 2021 |
| AJV Nest Ltd | Real estate | 2025 |
| Akako Limited | Professional & scientific | 2022 |
| AKO Barber Ltd | Other services | 2020 |
| Alan Mann Aviation Group Limited | Manufacturing | 1968 |
| Albert Road Freehold Limited | Real estate | 2013 |
| Alderash Limited | Construction | 2015 |
| Aleks & Andersen Ltd | Administrative & support | 2022 |
| Alerdale Properties Limited | Real estate | 1967 |
| Alerup Limited | Wholesale & retail | 2019 |
| Alex Cretney Limited | Information & communication | 2019 |
| Alex Tart Architects Limited | Professional & scientific | 2013 |
| Alexa Williamson Limited | Real estate | 2025 |
| Alexandra Court (Teddington) Limited | Households | 2003 |
| Alfredo Advisors Limited | Professional & scientific | 2025 |
| Alfredo Bello & Business Associates Ltd | Professional & scientific | 2023 |
| Alfresco Floors Limited | Wholesale & retail | 2014 |
| Algarve Winter Villas Limited | Administrative & support | 2025 |
| ALI 2016 Limited | Hospitality | 2025 |
| Alison Gabb Consultancy Limited | Administrative & support | 2009 |
| ALL Fingers & Thumbs Ltd | Professional & scientific | 2012 |
| Allied Resource Recruitment Ltd | Administrative & support | 2018 |
| Allmet Food Ltd | Hospitality | 2022 |
| Allsquare Properties Group Limited | Real estate | 2025 |
| Alpha (Teddington) Ltd | Professional & scientific | 2014 |
| Alpha Claygate Ltd | Professional & scientific | 2014 |
| Alphabet City Limited | Real estate | 1990 |
| ALR Entertainment Ltd | Other services | 2023 |
| ALY Gadalla Ltd | Construction | 2014 |
| AM Ventures Ltd | Professional & scientific | 2020 |
| Amaley Limited | Hospitality | 2019 |
| Amalgama Art Ltd | Wholesale & retail | 2019 |
| Amanda Allan Communications Limited | Professional & scientific | 2021 |
| Amanda Gunn Film Editing Limited | Information & communication | 2018 |
| Amanda Holliday Consulting Limited | Health & social care | 2004 |
| Amandina Limited | Health & social care | 2006 |
| Amaze Property Limited | Real estate | 2009 |
| Amba and Tondar Ltd | Households | 2024 |
| Amedes Limited | Construction | 2022 |
| Amex and Rodgers Ltd | Wholesale & retail | 2021 |
| Amia Data Technologies Limited | Information & communication | 2019 |
| Amia Projects Limited | Professional & scientific | 2015 |
| Ammonite 2000 Limited | Wholesale & retail | 2004 |
| Amsa Elite Group Ltd | Administrative & support | 2025 |
| Analytic Holdings Limited | Financial services | 2020 |
| Analytic Limited | Construction | 1999 |
| Anand Devaraj Limited | Health & social care | 2014 |
| And-Ray Electricals Ltd | Construction | 2015 |
| Andari Ltd | Transport & logistics | 2018 |
| Andrea Cuadrado Limited | Information & communication | 2016 |
| Andrew Garland Associates Limited | Information & communication | 2009 |
| Andrew Last Ltd | Professional & scientific | 2024 |
| Andrew Skeet Limited | Arts & recreation | 2015 |
| Andy Animates Ltd | Information & communication | 2017 |
| Anew Roofing and Sons Limited | Construction | 2012 |
| Angelos Angeli Limited | Other services | 2011 |