| Universal Phoenix Limited | Wholesale & retail | 2011 |
| Universal Soul Service Limited | Professional & scientific | 2015 |
| Universal Tiles and Floorings Ltd | Construction | 2025 |
| Universal Trade Services Limited | Manufacturing | 1983 |
| Universal Vibes Limited | Professional & scientific | 2017 |
| Universalbudgetltd Ltd | Wholesale & retail | 2024 |
| Universeal Home Improvements Limited | Construction | 2018 |
| Univo Ltd | Wholesale & retail | 2021 |
| Uniworld International Limited | Education | 2023 |
| Unknown Pleasures Limited | Wholesale & retail | 2018 |
| Unlimited Choice Ltd | Information & communication | 2016 |
| Unlimited Resources Limited | Construction | 2019 |
| Unmatched Solutions Limited | Information & communication | 2016 |
| Unmuted Tones Ltd | Wholesale & retail | 2025 |
| UNO1 International UK Limited | Wholesale & retail | 2024 |
| Unplugged Electrical Ltd | Construction | 2014 |
| Unstoppables Digital Media Ltd | Information & communication | 2023 |
| Untapped Consulting Ltd | Professional & scientific | 2018 |
| Until the Lions Ltd | Hospitality | 2023 |
| Unum Magnum Feriatum Ltd | Administrative & support | 2019 |
| Unyield Group Ltd | Wholesale & retail | 2026 |
| Unyk Limited | Wholesale & retail | 2010 |
| UOG Consulting Ltd | Professional & scientific | 2025 |
| UP & Shiny Ltd | Administrative & support | 2022 |
| UP North Session Orchestra Limited | Professional & scientific | 2015 |
| UP Stairlift (Africa) Ltd | Wholesale & retail | 2022 |
| Upbeta Logistic Ltd | Transport & logistics | 2019 |
| Upco Limited | Administrative & support | 1994 |
| Uplands and Summit House Ltd | Households | 2005 |
| Upminster Demolition and Haulage Limited | Construction | 2018 |
| Upper Crust (Harrow) Limited | Manufacturing | 2005 |
| Upper Local Store Ltd | Wholesale & retail | 2024 |
| Upper Putney Place Management Company Limited | Households | 1997 |
| UPS Solutions Ltd | Health & social care | 2009 |
| Upside Invest Limited | Real estate | 2022 |
| Upstairs Downstairs Films & TV Productions Limited | Information & communication | 2022 |
| Upstandard Ltd | Arts & recreation | 2025 |
| Upwizeai Ltd | Information & communication | 2025 |
| UR Pro FIX Services Ltd | Construction | 2025 |
| UR Properties & Management Limited | Real estate | 2005 |
| Uran Property Limited | Construction | 2020 |
| Urban Beat Films Ltd | Information & communication | 2026 |
| Urban Constructors Ltd | Construction | 2025 |
| Urban Equity Consultancy Ltd | Professional & scientific | 2025 |
| Urban Jungle Construction Limited | Construction | 2023 |
| Urban Keys Group Limited | Real estate | 2012 |
| Urban Locksmiths Ltd | Administrative & support | 2024 |
| Urban Mavericks Limited | Real estate | 2018 |
| Urban Nest Infra Ltd | Real estate | 2024 |
| Urban Orbit Limited | Wholesale & retail | 2025 |
| Urban Plan Consultants Ltd | Construction | 2019 |
| Urban Planter Ltd | Agriculture & fishing | 2025 |
| Urban Plaza Ltd | Hospitality | 2020 |
| Urban Property Compliance Ltd | Construction | 2026 |
| Urban Revenue Holding Limited | Financial services | 2024 |
| Urban Revenue Limited | Hospitality | 2024 |
| Urban Site Services Ltd | Construction | 2024 |
| Urban Super Strength Limited | Wholesale & retail | 2019 |
| Urban Threads & Soles Ltd | Wholesale & retail | 2025 |
| Urban Vista Ventures Ltd | Real estate | 2025 |
| Urban Wallcraft Limited | Construction | 2025 |
| Urban Wellness 360 Limited | Health & social care | 2021 |
| Urbanaut Limited | Real estate | 2021 |
| Urbanpickco Ltd | Wholesale & retail | 2026 |
| Urbanrevive Realty Limited | Construction | 2025 |
| Urbanscope Limited | Hospitality | 1993 |
| Urbansite Facilities Limited | Construction | 2026 |
| Urbanstone Developments & Home Improvements Ltd | Administrative & support | 2025 |
| Urbantech Consulting Ltd | Information & communication | 2024 |
| Urbanzupdi Ltd | Real estate | 2023 |
| Urgent Dental Practice Limited | Health & social care | 2010 |
| Urologists London Limited | Health & social care | 2014 |
| Uruk IT Solutions Limited | Information & communication | 2022 |
| Urvashi Limited | Real estate | 2016 |
| US Consultancy Limited | Wholesale & retail | 2026 |
| US Limousine UK Limited | Wholesale & retail | 2025 |
| US Trusworthy 1 Ltd | Real estate | 2021 |
| US Trusworthy 2 Ltd | Real estate | 2022 |
| US Trusworthy 3 Ltd | Real estate | 2022 |
| US Trusworthy Build Ltd | Real estate | 2024 |
| US Trusworthy Ltd | Real estate | 2021 |
| US Visa Agents Ltd | Professional & scientific | 2022 |
| USA V/S RAJ Productions Ltd | Information & communication | 2025 |
| Usciuc Construction Ltd | Construction | 2021 |
| Useful Amalgamated Ltd | Information & communication | 2018 |
| Ush.P. Properties Ltd | Real estate | 2025 |
| USI Corporation Ltd | Construction | 2019 |
| USI Infrastructure Ltd | Construction | 2021 |
| USI Investments Ltd | Construction | 2019 |
| Ustad Investments Ltd | Financial services | 2016 |
| USV Waste Management Ltd | Water & waste | 2026 |
| UTA Development Ltd | Real estate | 2021 |
| Utaja Limited | Real estate | 2023 |
| UTD Esports Ltd | Other services | 2019 |
| Uthra Foods (UK) Ltd | Construction | 2019 |
| Utility Box Limited | Professional & scientific | 2022 |
| Utopia Financial Partners Limited | Financial services | 2012 |
| Utopia Vision Limited | Information & communication | 2014 |
| UTS Heating Ltd | Construction | 2026 |
| UTX Digital Solutions Ltd | Information & communication | 2022 |