| Twenty Two Pillars Payroll Limited | Professional & scientific | 2026 |
| TWH Building Limited | Construction | 2020 |
| Twilight Education Ltd | Administrative & support | 2023 |
| Twingo Network Limited | Wholesale & retail | 2013 |
| Twinwheel European Limited | Transport & logistics | 2021 |
| Twinwheel Holdings Limited | Financial services | 2019 |
| Twinwheel Logistics Limited | Transport & logistics | 2017 |
| Twinwheel Pallet System Limited | Transport & logistics | 2021 |
| Twisted Hair and Beauty Ltd | Other services | 2013 |
| Twisted Hair on the Hill Limited | Other services | 2021 |
| Twister Solutions Limited | Information & communication | 2003 |
| Two Fifty Plus Ltd | Real estate | 2025 |
| Twyford Court Management (Dunmow) Limited | Real estate | 1996 |
| TX Contracts Limited | Administrative & support | 2018 |
| TY G Interiors Limited | Construction | 2019 |
| TYJ Consultancy Ltd | Professional & scientific | 2024 |
| Tyle Limited | Construction | 2022 |
| Tylissos Ltd | Hospitality | 2025 |
| Tymm's Tiling Limited | Construction | 2023 |
| Tynedale Properties Limited | Construction | 2024 |
| Tyza Build Ltd | Real estate | 2024 |
| Tyza Development Ltd | Construction | 2022 |
| TZ Engineering Limited | Professional & scientific | 2022 |
| TZR Services Ltd | Transport & logistics | 2026 |
| TØJ London Limited | Real estate | 2018 |
| U.K. Window Controls Ltd | Extraterritorial | 2012 |
| Ucabb Holdings Ltd | Real estate | 2025 |
| UK 383 Ltd | Manufacturing | 2026 |
| UK Asbestos Solutions Ltd | Construction | 2019 |
| UK Fire Doors Service Ltd | Construction | 2024 |
| UK Futsal Festivals Ltd | Arts & recreation | 2025 |
| UK Futsal Leagues CIC | Arts & recreation | 2024 |
| UK Goods Transport Ltd | Transport & logistics | 2022 |
| UK Industrial London Limited | Real estate | 1999 |
| UK Mastic Applicators Limited | Construction | 2015 |
| UK Moves Group Ltd | Transport & logistics | 2021 |
| UK Pro-Gifts Ltd | Administrative & support | 2019 |
| UK Security Fencing Ltd | Administrative & support | 2022 |
| UK Shelving Limited | Wholesale & retail | 1995 |
| UK Solar & Battery Ltd | Construction | 2023 |
| UK Untouchable Cover Ltd | Professional & scientific | 2025 |
| UK Waste Direct 2000 Limited | Water & waste | 2023 |
| UK Waste Direct Limited | Extraterritorial | 2020 |
| Uk-Doctorchef Limited | Administrative & support | 2016 |
| Ukgbrunch Ltd | Hospitality | 2018 |
| Ukmdc Ltd | Construction | 2017 |
| Ukraine Issuance PLC | Financial services | 2007 |
| Uktcg Limited | Administrative & support | 2026 |
| Ukzim Freight & Containers Ltd | Transport & logistics | 2025 |
| Uloidy Property Management Limited | Real estate | 2026 |
| Ultimate Business Support Limited | Administrative & support | 2025 |
| Ultimate Pharma Solutions Ltd | Health & social care | 2023 |
| Ultimate Solutions in Security Limited | Administrative & support | 2019 |
| Ultra Events (Essex) Ltd | Professional & scientific | 2020 |
| Ultras Care Limited | Public administration | 2022 |
| UMA Developers Limited | Real estate | 2022 |
| UMA Enterprise Ltd | Wholesale & retail | 2024 |
| UMA Traders Ltd | Wholesale & retail | 2022 |
| UNC Saucy Ltd | Hospitality | 2022 |
| Uncle Kams Basildon Ltd | Hospitality | 2018 |
| Unclear Origins Ltd | Manufacturing | 2021 |
| Underjaw Ltd | Wholesale & retail | 2020 |
| Uneqk Power Limited | Other services | 2019 |
| Unexpected Value Limited | Other services | 2021 |
| Unibekk Care Services Limited | Health & social care | 2018 |
| Unicorn Professional Services Limited | Professional & scientific | 2014 |
| Unified Europe Ltd | Wholesale & retail | 2015 |
| Unified Web Services Ltd | Information & communication | 2023 |
| Unify Financial Advisers Limited | Financial services | 2025 |
| Unique Financial Solutions Group Limited | Professional & scientific | 2004 |
| Unique Office Solutions (Holdings) Limited | Manufacturing | 2023 |
| Unique Smiles Childcare Services Ltd | Health & social care | 2024 |
| Uniqueteam Ltd | Construction | 2018 |
| Unit 2 Distribution Ltd | Transport & logistics | 2026 |
| Unit Export Limited | Wholesale & retail | 1977 |
| United Genesis Ltd | Financial services | 2013 |
| United Maritime Crewing Services Limited | Administrative & support | 2017 |
| United Thermal Insulation Ltd | Construction | 2023 |
| United Treasures CIC | Wholesale & retail | 2026 |
| Universal LED Merchants Ltd | Wholesale & retail | 2021 |
| Universal Spraying Limited | Manufacturing | 2013 |
| Universaltech Solutions Ltd | Information & communication | 2020 |
| Unkind Hands Ltd | Manufacturing | 2025 |
| Unpuzzled Theatre Company C.I.C. | Education | 2022 |
| Untamed Arena Limited | Real estate | 2024 |
| Untouchable Limited | Information & communication | 2025 |
| UP Scaffolding Ltd | Construction | 2013 |
| UP the Road Takeaway Ltd | Hospitality | 2025 |
| Upleatham House Management Limited | Real estate | 2008 |
| Uplevel Group Ltd | Administrative & support | 2025 |
| Uplift Technologies Ltd | Professional & scientific | 2025 |
| Upper Glass Conservatories Limited | Construction | 2005 |
| Upscale Cloud Limited | Real estate | 2024 |
| Upscale Cloud Technologies Ltd | Information & communication | 2024 |
| Upsizing Limited | Wholesale & retail | 2025 |
| Upstream Tubulars Ltd | Mining & quarrying | 2010 |
| Uptec Limited | Professional & scientific | 2025 |
| Uptown Cars (U.K) Limited | Wholesale & retail | 2024 |
| Urban Tech Security Limited | Administrative & support | 2022 |
| Urban Tribe Trading Limited | Wholesale & retail | 2025 |