| Ultc Academy Ltd | Other services | 2024 |
| Ultrapolis Lifesciences Private Limited | Extraterritorial | 2022 |
| Umaimen Books Ltd | Education | 2021 |
| Umbralux Electric Ltd | Construction | 2025 |
| Un-Gap Learning & System Solutions Ltd | Information & communication | 2025 |
| Unboxing Ltd | Extraterritorial | 2025 |
| Uncovr Ltd | Information & communication | 2025 |
| Underdogs Entertainment Limited | Information & communication | 2026 |
| Underland London Limited | Wholesale & retail | 2023 |
| Uneique Ltd | Arts & recreation | 2021 |
| Unibond Seafood International Limited | Wholesale & retail | 2017 |
| Unibrook Limited | Financial services | 2021 |
| Unibuild Group Ltd | Construction | 2019 |
| Unicon Traders Ltd | Wholesale & retail | 2018 |
| Unicron Ltd | Professional & scientific | 2026 |
| Uniden Ltd | Manufacturing | 2021 |
| Unigrove Limited | Real estate | 2017 |
| Union Jack Productions Ltd | Construction | 2014 |
| Unipride Ventures Limited | Financial services | 2012 |
| Uniqademy Education Services Ltd | Education | 2025 |
| Uniqly Ltd | Information & communication | 2022 |
| Unique Car Body Repairs Limited | Wholesale & retail | 2023 |
| Unique Carpentry Solutions Ltd | Construction | 2022 |
| Unique Glazing and Plastics Ltd | Construction | 2017 |
| Unique Glazing London Ltd | Manufacturing | 2016 |
| Unique Healthcare Hub Ltd | Health & social care | 2022 |
| Unique Home Construction Ltd | Construction | 2020 |
| Unique London Properties Limited | Construction | 2014 |
| Unique Rigging Limited | Construction | 2023 |
| Unique Trends Development Limited | Construction | 2024 |
| UNIQUE2 Ltd | Hospitality | 2021 |
| Uniquely Crafted Limited | Wholesale & retail | 2023 |
| United Finsure Limited | Professional & scientific | 2024 |
| United Fintec Limited | Information & communication | 2016 |
| United Kingdom Industry Ltd | Wholesale & retail | 2020 |
| United Kingdom Parts Limited | Wholesale & retail | 2020 |
| United Lift Network Group Ltd | Information & communication | 2020 |
| United Looks Limited | Wholesale & retail | 2025 |
| United Martial Arts Academy Ltd | Arts & recreation | 2020 |
| United Property 2001 Limited | Administrative & support | 2001 |
| United Timber Ltd | Manufacturing | 2020 |
| Universal Call Limited | Information & communication | 2013 |
| Universal Quality Buildings Ltd | Construction | 2019 |
| Unmanned Flight Services Limited | Professional & scientific | 2018 |
| Unyielding Ltd | Hospitality | 2025 |
| UP the Ladder Ltd | Real estate | 2020 |
| Upgrade Pest Control Limited | Other services | 2007 |
| Uphill Foods Ltd | Hospitality | 2026 |
| Uplands (Fareham) Limited | Health & social care | 1998 |
| UPM Conveyors Holdings Limited | Financial services | 2022 |
| UPM Conveyors Limited | Manufacturing | 1975 |
| Upperhouse Management Ltd | Construction | 2020 |
| Upshot Engineering UK Limited | Professional & scientific | 2025 |
| Upwards Rigging Ltd | Other services | 2026 |
| Urano Investments Limited | Financial services | 2016 |
| Urban BK Ltd | Construction | 2023 |
| Urban Blocks Limited | Hospitality | 2024 |
| Urban Chapters Ltd | Real estate | 2024 |
| Urban EGG Limited | Real estate | 2020 |
| Urban Kitchen & Bedroom Specialists Ltd | Construction | 2021 |
| Urban Oasis Exterior Services Ltd | Construction | 2025 |
| Urban Root Kitchen Limited | Manufacturing | 2025 |
| Urban Traffic Management Solutions Ltd | Administrative & support | 2025 |
| Usama and Chilli Milli Limited | Wholesale & retail | 2025 |
| Usherwood Limited | Construction | 2019 |
| Usman Mian Consulting Ltd | Professional & scientific | 2014 |
| Uuwt New Build Ltd | Construction | 2018 |
| UXB One Ltd | Hospitality | 2018 |
| UXB Two Ltd | Hospitality | 2018 |
| Uxbridge Animal Health Limited | Extraterritorial | 2019 |
| Uxbridge Art Bar Ltd | Hospitality | 2025 |
| Uxbridge Boat Centre Limited | Transport & logistics | 1976 |
| Uxbridge Chicken & Burgers Ltd | Hospitality | 2026 |
| Uxbridge Food Ltd | Hospitality | 2024 |
| Uxbridge Hair Ltd | Other services | 2020 |
| Uxbridge Halal Butchers Ltd | Wholesale & retail | 2026 |
| Uxbridge High School Academy Trust | Education | 2011 |
| Uxbridge Infra Tech Ltd | Information & communication | 2025 |
| Uxbridge IVY Leaf Club | Hospitality | 2024 |
| Uxbridge MOT and Services Ltd | Wholesale & retail | 2025 |
| Uxbridge Scooters Limited | Wholesale & retail | 2001 |
| Uxbridge United Welfare Trust | Administrative & support | 2018 |
| Uyhd Limited | Real estate | 2026 |
| V & K Plus Limited | Construction | 2025 |
| V Build Contractors Ltd | Construction | 2025 |
| V Dolea Transport Ltd | Construction | 2018 |
| V G Food & Wine Ltd | Wholesale & retail | 2010 |
| V J Groundworks Limited | Administrative & support | 2019 |
| V&A Management Portfolio Limited | Professional & scientific | 2014 |
| V&N Wines Limited | Information & communication | 2025 |
| V&P Property Limited | Real estate | 2018 |
| V&S Entertainment (L&M) Ltd | Arts & recreation | 1996 |
| V&S Entertainment Ltd | Arts & recreation | 1991 |
| V-Ar Homes Ltd | Real estate | 2024 |
| V.D.D Construction Ltd | Construction | 2022 |
| V.I.P GAS & Heating Ltd | Construction | 2024 |
| Vadakkedom Holdings Limited | Real estate | 2024 |
| Vale Development Nationwide Limited | Construction | 2015 |
| Valent Leadership Ltd | Professional & scientific | 2025 |
| Valentino Entertainments Ltd | Professional & scientific | 2015 |