| TT Tyres London Ltd | Wholesale & retail | 2025 |
| TTP Europe Ltd | Arts & recreation | 2025 |
| Ttra LLP | | 2017 |
| TUC Group Ltd | Real estate | 2021 |
| TUC Properties Ltd | Real estate | 2021 |
| Tulina Home Appliances Ltd | Wholesale & retail | 2026 |
| Tungsten Law Ltd | Administrative & support | 2017 |
| Tungsten Legal Consultancy Limited | Professional & scientific | 2016 |
| Turners Lettings Limited | Real estate | 2013 |
| Turners Property Limited | Real estate | 2013 |
| Turuc Contractors Ltd | Manufacturing | 2025 |
| Tuspec Limited | Construction | 2014 |
| Tutelage Consultants Ltd | Education | 2021 |
| Tutor Briefcase Limited | Information & communication | 2026 |
| Tutor Zone Limited | Education | 2015 |
| TW3 Moto Group Ltd | Other services | 2026 |
| TWENTY2 Developments Ltd | Construction | 2022 |
| Twerk'N'Jerk Events Limited | Hospitality | 2025 |
| Twin Ladles Kitchen Limited | Hospitality | 2026 |
| Twoview Properties Ltd | Real estate | 2023 |
| Tyson Ceilings and Partitions Ltd | Construction | 2010 |
| Ua-Uk Electrical Service Ltd | Construction | 2022 |
| UAI Financial Partners Limited | Real estate | 2019 |
| UB4 Care Limited | Health & social care | 2025 |
| Uber Meds Limited | Education | 2021 |
| Ubique Security Services Ltd | Information & communication | 2019 |
| Uday IT Solutions Limited | Information & communication | 2012 |
| UF Traders Ltd | Hospitality | 2021 |
| Ufirst Enterprises Limited | Wholesale & retail | 2017 |
| Ugam Limited | Health & social care | 2025 |
| UK Accounting & Finance Limited | Information & communication | 2011 |
| UK Car Giant Limited | Wholesale & retail | 2013 |
| UK Car Private Hire Ltd | Transport & logistics | 2019 |
| UK Carparts International Ltd | Wholesale & retail | 2025 |
| UK Charm Enterprises Limited | Other services | 2014 |
| UK Cladding Ltd | Construction | 2019 |
| UK Driver Solutions Limited | Transport & logistics | 2018 |
| UK Global Tax Ltd | Administrative & support | 2025 |
| UK Home Care Solutions Ltd | Other services | 2018 |
| UK Multitech Engineering Limited | Wholesale & retail | 2024 |
| UK Omni Cart Ltd | Wholesale & retail | 2026 |
| UK Property Hub Limited | Households | 2012 |
| UK Spares 27 Ltd | Wholesale & retail | 2025 |
| UK Vion Ltd | Construction | 2021 |
| Ukacsp Ltd | Information & communication | 2026 |
| Uknergy Limited | Professional & scientific | 2024 |
| UKQ8 Limited | Administrative & support | 2024 |
| Ulez Testing UK Ltd | Professional & scientific | 2021 |
| Ultimate Build Teams Limited | Construction | 2016 |
| Ultimate Complete Care Ltd | Administrative & support | 2022 |
| Ultimate Contractors Ltd | Construction | 2019 |
| Umaria Ltd | Information & communication | 2014 |
| Umbreltech Ltd | Wholesale & retail | 2026 |
| Umiko Ltd | Hospitality | 2025 |
| UMK Trading Ltd | Education | 2017 |
| Umoya Limited | Construction | 2021 |
| Unblur Ltd | Information & communication | 2022 |
| Unicon Tyres Limited | Wholesale & retail | 2014 |
| Union Profit Limited | Manufacturing | 2006 |
| Unique Choice Travel & Tour Ltd | Administrative & support | 2025 |
| Unique Print, Advertising & Graphics Ltd. | Manufacturing | 2022 |
| Unique Summit Limited | Real estate | 2019 |
| Unique Travels and Tours UK Ltd | Administrative & support | 2024 |
| Unique Village Limited | Health & social care | 2025 |
| Unispire Group Ltd | Professional & scientific | 2026 |
| United Core Ltd | Wholesale & retail | 2026 |
| United GAS Boiler and Electrical Services Ltd | Manufacturing | 2016 |
| United Metals Ltd | Wholesale & retail | 2020 |
| Unitere Ltd | Construction | 2024 |
| Unities Support Ltd | Administrative & support | 2025 |
| Universal Accounting Ltd | Professional & scientific | 2017 |
| Universal Accounts Ltd | Professional & scientific | 2015 |
| Universal Services Group Ltd | Information & communication | 2020 |
| Universal Traders Ltd | Construction | 2025 |
| Universey Candle Store Ltd | Wholesale & retail | 2024 |
| Unknown Systems Ltd | Information & communication | 2023 |
| UNO Driving School Ltd | Other services | 2018 |
| Uponstore Ltd | Wholesale & retail | 2026 |
| Uptown Flava Group Limited | Hospitality | 2023 |
| UR Ventures Limited | Wholesale & retail | 2026 |
| Urban Blends Coffee Ltd | Hospitality | 2025 |
| Urban Business Group Ltd | Real estate | 2015 |
| Urban Concepts SPV Ltd | Households | 2022 |
| Urban Residencia Limited | Real estate | 2022 |
| Urban Residential Management Limited | Real estate | 2023 |
| Urban Square Homes Ltd | Real estate | 2019 |
| Urban Trends London Limited | Construction | 2013 |
| Urbanends Estates Ltd | Real estate | 2020 |
| Urdu Books World Ltd | Wholesale & retail | 2026 |
| URO & Andrology Medical Care Ltd | Health & social care | 2026 |
| USA Garage Ltd | Wholesale & retail | 2025 |
| Usmanqurat Limited | Professional & scientific | 2023 |
| V & S Properties Ltd | Real estate | 2022 |
| V&E London Limited | Construction | 2015 |
| V14 Investments Ltd | Real estate | 2020 |
| V14 Services Ltd | Information & communication | 2018 |
| Vaami Property Investment Ltd | Real estate | 2026 |
| Valbos Ltd | Transport & logistics | 2024 |
| Vale House Management Limited | Households | 1982 |
| Valeriia Properties Limited | Real estate | 2024 |