| Trinity Gardens (Gravesend) NO.2 Residents Company Limited | Households | 1991 |
| Trinity School Sevenoaks Ltd | Education | 2012 |
| Trioss Group Limited | Construction | 2022 |
| Tristar Digital Ltd | Professional & scientific | 2021 |
| Troika 23 Limited | Administrative & support | 2023 |
| Trojan.Systems Ltd | Manufacturing | 2023 |
| Trotting OUT Business Services Ltd | Other services | 2022 |
| Troutbeck House Limited | Households | 2000 |
| Troutbeck Services Limited | Households | 2002 |
| True Conservative Media Ltd | Wholesale & retail | 2023 |
| True Expressions Balance Limited | Wholesale & retail | 2010 |
| Truetide Advisory Ltd | Professional & scientific | 2025 |
| Truhairstudio Ltd | Other services | 2026 |
| Trump Electrical Ltd | Construction | 2020 |
| Trust Bricks Group Ltd | Information & communication | 2020 |
| Trust Bricks Ltd | Information & communication | 2020 |
| Trust Wellness Ltd | Wholesale & retail | 2017 |
| Tryco Limited | Financial services | 2023 |
| Trying IS Good Productions Limited | Information & communication | 2025 |
| Tsap Consulting Limited | Information & communication | 2005 |
| TSC Consulting Engineers Ltd | Professional & scientific | 2020 |
| TSC Holdings Limited | Professional & scientific | 2017 |
| Tspt Ltd | Education | 2011 |
| Tsuru Group Limited | Professional & scientific | 2024 |
| TTI Limited | Wholesale & retail | 2009 |
| TTP Consultants Ltd | Professional & scientific | 2001 |
| Ttsfx Limited | Arts & recreation | 2014 |
| TTU Holdings Limited | Financial services | 2023 |
| Tulip Bespoke Ltd | Construction | 2007 |
| Tulmul Investments Ltd | Real estate | 2024 |
| Tuna Media Limited | Information & communication | 2008 |
| Turbo 3000 Ltd | Professional & scientific | 2025 |
| Turbo Trading Limited | Construction | 2012 |
| Turners M+E Ltd | Education | 2024 |
| Turuk House Ltd | Real estate | 2025 |
| Turvey Solutions Ltd | Health & social care | 2019 |
| Turvins Ltd | Manufacturing | 2026 |
| Tusa Holdings Ltd | Real estate | 2024 |
| TW Consulting Group Ltd | Administrative & support | 2017 |
| TW Music Production Ltd | Arts & recreation | 2019 |
| TWD Events Ltd | Other services | 2020 |
| Twelve Bar Management Limited | Real estate | 2013 |
| Twizler Limited | Wholesale & retail | 2000 |
| Two+More Ltd | Professional & scientific | 2024 |
| Twothestrand Ltd | Wholesale & retail | 2021 |
| Tython Ltd | Information & communication | 2015 |
| TZ Welding Ltd | Construction | 2015 |
| UAE NOW Ltd | Professional & scientific | 2025 |
| Uavend Exeter LLP | | 2015 |
| Ubiquiem Limited | Information & communication | 2010 |
| Udonate Limited | Health & social care | 2022 |
| UK Bags Elite Limited | Administrative & support | 2004 |
| UK Certification Authority for Reinforcing Steels | Professional & scientific | 1983 |
| UK China Polo Association | Arts & recreation | 2023 |
| UK Commercial Property Finance Limited | Financial services | 2019 |
| UK Dentmaster Ltd | Wholesale & retail | 2013 |
| UK Moto Assist Ltd | Wholesale & retail | 2025 |
| UK Smart Bathrooms Limited | Construction | 2020 |
| UK to ZIM Transport Ltd | Transport & logistics | 2024 |
| UK Water Treatment Limited | Construction | 2024 |
| Ukafinvestco Limited | Financial services | 2022 |
| Ukal NO3 Limited | Financial services | 2019 |
| Ukal NO4 Limited | Financial services | 2022 |
| Ukal NO5 Limited | Financial services | 2024 |
| Uknapp Ltd | Administrative & support | 2013 |
| Ultimate Construction Group Ltd | Construction | 2016 |
| Ultimate Creations Limited | Manufacturing | 2004 |
| Ultimate Dent Removal Ltd | Wholesale & retail | 2010 |
| Ultimate Finish Painting & Decorating Limited | Construction | 2016 |
| Ultion Holdings Limited | Financial services | 2023 |
| Ultra 2025 UK Limited | Transport & logistics | 2025 |
| Ultratest Limited | Administrative & support | 2012 |
| Umbrella Ventures Ltd | Professional & scientific | 2025 |
| Un-Limited Motorsport Ltd | Manufacturing | 2024 |
| Undercore Ltd | Construction | 2023 |
| Undercroft Mayfair Limited | Hospitality | 2022 |
| Unialco LLP | | 2018 |
| Unice Engineering Limited | Manufacturing | 1992 |
| Unicorn Strategy Partners Ltd | Professional & scientific | 2023 |
| Union Mgmt Ltd | Administrative & support | 2014 |
| Unit List Ltd | Information & communication | 2026 |
| United African Utilities Ltd | Construction | 2020 |
| United Asphalt Limited | Extraterritorial | 2007 |
| United Global Capital Ltd | Financial services | 2017 |
| United Global Group Ltd | Real estate | 2018 |
| United Global Homes Ltd | Construction | 2016 |
| United Global Ltd | Real estate | 2018 |
| United Global Property Ltd | Real estate | 2017 |
| United Global Services Ltd | Construction | 2011 |
| United Kingdom Property Centre Limited | Real estate | 2020 |
| Unity Consolidated Holdings Limited | Financial services | 2024 |
| Unity Fitness Kent Limited | Arts & recreation | 2022 |
| Universal Smile Ltd | Health & social care | 2017 |
| Upshot Ventures Limited | Financial services | 2024 |
| Upside Management (UK) Ltd | Professional & scientific | 2012 |
| Uptex Limited | Construction | 2020 |
| Uptex Luxury Finishes Ltd | Construction | 2025 |
| Upton World Limited | Wholesale & retail | 2023 |
| Urban Breeze Developments Limited | Professional & scientific | 2015 |
| Urban Environments Limited | Administrative & support | 1998 |