| A to Z Courier 4U Limited | Transport & logistics | 2012 |
| A to Z Service Group Ltd | Education | 2026 |
| A Touch of Class (Wembley) Limited | Other services | 2016 |
| A&A Building Services Ltd | Construction | 2021 |
| A&A Clothing & Accessories Ltd | Wholesale & retail | 2023 |
| A&B Food Ltd | Wholesale & retail | 2025 |
| A&E Specialist Autos Ltd | Wholesale & retail | 2025 |
| A&G Building Solutions Limited | Construction | 2014 |
| A&H Metal Works Limited | Manufacturing | 2023 |
| A&H Realty Limited | Real estate | 2026 |
| A&K Henderson Limited | Real estate | 2021 |
| A&O Construction Ltd | Construction | 2021 |
| A&O Glazing Ltd | Construction | 2025 |
| A&P Hunter (Construction) Limited | Construction | 2004 |
| A&S Gifts Ltd | Wholesale & retail | 2023 |
| A'Neil Brittanny Ltd | Wholesale & retail | 2019 |
| A-Fone Solutions Ltd | Wholesale & retail | 2019 |
| A-Z Master Builders Ltd | Administrative & support | 2022 |
| A-Z Sudbury Ltd | Wholesale & retail | 2012 |
| A.C.L. Scaffold Services Limited | Construction | 2016 |
| A.Dot.Js Ltd | Transport & logistics | 2024 |
| A.F Haulage Ltd | Wholesale & retail | 2026 |
| A.Kutz Ltd | Other services | 2021 |
| A.O.A Compliance Consulting Limited | Administrative & support | 2014 |
| A.R & Co International Ltd | Professional & scientific | 2026 |
| A.R.T. Safe Storage Archive Ltd. | Other services | 2019 |
| A.R.T. Training and Consultancy Services Ltd | Other services | 2014 |
| A.T Mount Properties Limited | Real estate | 2021 |
| A.T.A Clinic Ltd | Health & social care | 2024 |
| A1 Craft Ltd | Wholesale & retail | 2020 |
| A1 Entertainment Ltd | Arts & recreation | 2022 |
| A1 Gifts Ltd | Wholesale & retail | 2017 |
| A2B Home Markets Ltd | Wholesale & retail | 2025 |
| A2B Sports Management Ltd | Arts & recreation | 2021 |
| A2C Dream Factory Limited | Arts & recreation | 2019 |
| A2DC Electrical Services Ltd | Construction | 2026 |
| A2G Home Renovations Ltd | Construction | 2025 |
| A2Z Best Deals Ltd | Professional & scientific | 2025 |
| A2Z Commercial Exports Ltd | Wholesale & retail | 2024 |
| A2Z Estate Agency Limited | Real estate | 2015 |
| A2Z Recruitment Solutions Ltd | Administrative & support | 2012 |
| A3 Beauty Clinic Limited | Other services | 2025 |
| AA Designer Collection Limited | Wholesale & retail | 2019 |
| AA GAS & Plumbing Services Limited | Construction | 2025 |
| AA Housing Recovery Ltd | Construction | 2025 |
| AA Precision Plumbing Ltd | Construction | 2026 |
| AA PUB Holdings Limited | Wholesale & retail | 2025 |
| AAA Collection Ltd | Real estate | 2026 |
| AAA Logistic Transport Ltd | Transport & logistics | 2024 |
| Aaaa Foods Ltd | Hospitality | 2021 |
| Aaad Ventures Ltd | Wholesale & retail | 2023 |
| Aaag Ltd | Wholesale & retail | 2025 |
| Aaaisz Limited | Wholesale & retail | 2021 |
| Aaban & Co. Ltd | Information & communication | 2011 |
| Aadhar | Education | 2020 |
| Aadi Jaym Ltd | Information & communication | 2026 |
| Aadil Rashid Ltd | Information & communication | 2018 |
| AAE Wembley Limited | Manufacturing | 2025 |
| Aahienterprise Ltd | Wholesale & retail | 2023 |
| AAI25 Limited | Real estate | 2025 |
| Aais Tristar UK Ltd | Other services | 2017 |
| Aali Holdings Ltd | Other services | 2024 |
| Aama Group Limited | Real estate | 2016 |
| Aambika Ltd | Real estate | 2025 |
| Aana & Company Ltd | Transport & logistics | 2015 |
| AAR786 Ltd | Wholesale & retail | 2024 |
| Aarav Group of Companies Ltd | Wholesale & retail | 2026 |
| Aarav Sales Ltd | Wholesale & retail | 2025 |
| Aare Limited | Transport & logistics | 2019 |
| Aaren Ltd | Extraterritorial | 2024 |
| Aarna Online Retail Ltd | Wholesale & retail | 2025 |
| Aarohi & Indu Foods Ltd | Hospitality | 2025 |
| Aaron & Brendan Investment Ltd | Wholesale & retail | 2021 |
| Aaron Moniz Limited | Wholesale & retail | 2022 |
| Aarossian Ltd | Construction | 2014 |
| Aartee Ltd | Wholesale & retail | 2023 |
| Aaryamaan UK Ltd | Wholesale & retail | 2025 |
| AAS Supplies Ltd | Wholesale & retail | 2025 |
| Aashi and Mahi Properties Limited | Real estate | 2017 |
| Aashi Fashions Ltd | Wholesale & retail | 2016 |
| Aastha Care Ltd | Health & social care | 2023 |
| Aathiran & Co Limited | Wholesale & retail | 2020 |
| Aauum Limited | Wholesale & retail | 2021 |
| Aazj Ltd | Health & social care | 2021 |
| Aazzure Trading Ltd | Real estate | 2018 |
| AB Care Group Limited | Wholesale & retail | 2025 |
| AB Decore & Builder Limited | Construction | 2012 |
| AB Digital Systems Limited | Manufacturing | 2015 |
| AB FAB Services Ltd | Real estate | 2024 |
| AB Marketer Limited | Professional & scientific | 2019 |
| AB Views Limited | Real estate | 2021 |
| ABA Corporation Limited | Information & communication | 2010 |
| ABA Infinity Ltd | Construction | 2024 |
| Abaccus Ltd | Information & communication | 2022 |
| Abacus MAP Ltd | Education | 2008 |
| Abaka Tech Limited | Information & communication | 2022 |
| Abalta Limited | Administrative & support | 1999 |
| Abar Studio Ltd | Manufacturing | 2025 |
| Abbasi Brothers Ltd | Hospitality | 2020 |
| Abbey Mart Limited | Real estate | 2011 |