| A & V Building Ltd | Construction | 2019 |
| A a Bespoke Installations Ltd | Construction | 2024 |
| A and a London Limited | Wholesale & retail | 2003 |
| A and M Partners Limited | Professional & scientific | 2012 |
| A and U Capital Ltd | Wholesale & retail | 2016 |
| A Boom With a View Ltd | Information & communication | 2007 |
| A Brown Builders Holdings Ltd | Construction | 2013 |
| A J Furr Limited | Water & waste | 2019 |
| A J Hoarding Ltd | Construction | 2020 |
| A J Reform Limited | Professional & scientific | 2010 |
| A Little BIT of Day-Light Ltd | Construction | 2022 |
| A Little Find Ltd | Wholesale & retail | 2016 |
| A M Electrical Limited | Construction | 2002 |
| A M Management Consultants Limited | Professional & scientific | 1999 |
| A M P Estate Management Ltd | Real estate | 2025 |
| A Martens Kitchens & Bathrooms Ltd | Construction | 2014 |
| A MON Avis Ltd | Real estate | 2025 |
| A Niche Mortgages Ltd | Financial services | 2013 |
| A Photiou Marketing Ltd | Professional & scientific | 2024 |
| A Players Limited | Education | 2024 |
| A Property Management Staffordshire Limited | Construction | 2017 |
| A Space Designs Holdings Limited | Financial services | 2020 |
| A Space Designs Limited | Professional & scientific | 2015 |
| A Star Childminding Ltd | Health & social care | 2024 |
| A Star Teaching Ltd | Education | 2025 |
| A Star Vehicle Systems Ltd | Wholesale & retail | 2025 |
| A T S Project Solutions Ltd | Professional & scientific | 2018 |
| A Toolan Ltd | Real estate | 2018 |
| A W a Shopfitters Limited | Construction | 1997 |
| A&A Construction Limited | Construction | 2024 |
| A&A Relocation Properties Ltd | Hospitality | 2024 |
| A&B Brickwork Ltd | Construction | 2025 |
| A&B London Accountancy Ltd | Professional & scientific | 2023 |
| A&B Mechanical Services Limited | Construction | 2007 |
| A&F Associates Limited | Administrative & support | 2009 |
| A&G LDN Limited | Real estate | 2026 |
| A&H Events Ltd | Arts & recreation | 2018 |
| A&R Nielsen Limited | Professional & scientific | 2016 |
| A&S Home Care Services Ltd | Health & social care | 2024 |
| A&S Swift Limited | Wholesale & retail | 2025 |
| A&T Traders Ltd | Wholesale & retail | 2009 |
| A-Z Builders ALL Ltd | Construction | 2016 |
| A. L. I. Property Limited | Real estate | 1975 |
| A.A.S. Electrics Ltd | Manufacturing | 2020 |
| A.J.Fencing Ltd | Administrative & support | 2016 |
| A.M. Independent Assessments Limited | Health & social care | 2014 |
| A.Neophytou & Co Ltd | Professional & scientific | 2015 |
| A.R. Contracts Limited | Construction | 1992 |
| A.R.M.Y. Property Limited | Real estate | 2021 |
| A.T.Q. Soft Limited | Information & communication | 2012 |
| A1 City Cars Limited | Transport & logistics | 2025 |
| A1 Golf Outlet Limited | Wholesale & retail | 2013 |
| A1 Recycled Aggregates Limited | Water & waste | 2024 |
| A1DAN Ltd | Other services | 2013 |
| A2K 22 Limited | Real estate | 2022 |
| AA Hills Investment Ltd | Construction | 2025 |
| AA Management(Uk) Ltd | Professional & scientific | 2017 |
| AA Metal Force Ltd | Construction | 2022 |
| AA Plumbing Services Ltd | Construction | 2016 |
| AA365 Ltd | Professional & scientific | 2018 |
| AAA Cars Potters Bar Ltd | Transport & logistics | 2021 |
| AAA London Limited | Transport & logistics | 2017 |
| AAA Marketing Limited | Professional & scientific | 2017 |
| AAA Taxis (Contracts) Ltd | Transport & logistics | 2014 |
| AAA Taxis (GB) Limited | Transport & logistics | 2010 |
| AAA Taxis (Hatfield) Limited | Transport & logistics | 2014 |
| AAA Taxis (Herts) Ltd | Transport & logistics | 2014 |
| Aadhidaivika Consulting Ltd | Information & communication | 2018 |
| Aadhya Ziva Limited | Wholesale & retail | 2023 |
| Aaditya Enterprise Limited | Real estate | 2017 |
| Aaditya Medical Services Ltd | Health & social care | 2025 |
| Aafdev Associates Ltd | Professional & scientific | 2012 |
| Aahana Enterprise Ltd | Wholesale & retail | 2026 |
| Aamana Trading Ltd | Wholesale & retail | 2019 |
| AAN Electrical Services Ltd | Construction | 2020 |
| Aanda S&M Holdings Limited | Health & social care | 2025 |
| Aapi Ltd | Real estate | 2017 |
| AAR Abingdon Ltd | Hospitality | 2019 |
| Aarc Property Investment Ltd | Households | 2024 |
| Aarc Realty Ltd | Administrative & support | 2025 |
| Aarc Renovations Limited | Households | 2024 |
| Aaron Designs Limited | Administrative & support | 2015 |
| Aaronella Ltd | Wholesale & retail | 2022 |
| Aarvi Food Safety Services Limited | Professional & scientific | 2015 |
| AAS Projects & Design Ltd | Construction | 2016 |
| Aastra Bright Care Co Ltd | Health & social care | 2025 |
| Aavni Investment Limited | Real estate | 2013 |
| AAW Mechanical Pipework Services Limited | Construction | 2008 |
| Aayan Properties Ltd | Real estate | 2019 |
| AAZ Property Investments Ltd | Real estate | 2023 |
| AB Electrical & Installation Ltd | Wholesale & retail | 2022 |
| AB Estates & Maintenance Limited | Administrative & support | 2022 |
| AB Home Development Limited | Real estate | 2019 |
| AB Luton One Ltd | Real estate | 2023 |
| AB Travel and Marketing Limited | Administrative & support | 2025 |
| ABA Therapists Limited | Administrative & support | 2017 |
| Abacuspace Ltd | Information & communication | 2020 |
| Abbarci Coffee (UK) Limited | Financial services | 2024 |
| Abbey Accountants Limited | Professional & scientific | 2002 |
| Abbey IP Limited | Construction | 2005 |