| Tugwell Refurbishments Limited | Construction | 2025 |
| Tulip Accounting Solutions Limited | Professional & scientific | 2022 |
| Tulupa Limited | Administrative & support | 2019 |
| Tunks and Sons Ltd | Transport & logistics | 2018 |
| Tupa Energy (Holdings) Limited | Financial services | 2022 |
| Tupa Energy Limited | Construction | 2020 |
| Turas Counselling Services Ltd | Health & social care | 2022 |
| Turkish Grooming Ltd | Other services | 2025 |
| Turner Digital Ltd | Information & communication | 2018 |
| Turner Invest LLP | | 2015 |
| Turners Automotive Ltd | Wholesale & retail | 2021 |
| Turners Group Ltd | Construction | 2024 |
| Turnham & Hill Properties Limited | Construction | 2002 |
| Turoff Danbury Centre Limited | Health & social care | 2012 |
| Turoff Danbury Clinic Ltd | Health & social care | 2006 |
| Turret Lane Limited | Construction | 2018 |
| Tush Linc Limited | Health & social care | 2010 |
| Tusk Maintenance Ltd | Construction | 2023 |
| Tutorturn Limited | Education | 2021 |
| TVF Associates Ltd | Administrative & support | 2014 |
| TW Cranes Holdings Limited | Real estate | 2021 |
| TWE Technology Ltd | Information & communication | 2025 |
| Twentyone Digital Ltd | Information & communication | 2025 |
| Twig Construction Limited | Construction | 2017 |
| Twincross Consulting Ltd | Information & communication | 2023 |
| Twintone Ltd | Information & communication | 2025 |
| Twist Interactive Design Limited | Information & communication | 2010 |
| Twisted Play Limited | Information & communication | 2005 |
| Twizzle Tops Limited | Health & social care | 2021 |
| Twkala Consulting Ltd | Professional & scientific | 2018 |
| Two Browns Farm Ltd | Agriculture & fishing | 2026 |
| Two FIN Swim Ltd | Education | 2021 |
| Two Oaks Builders and Contractors Limited | Construction | 1998 |
| TWP Limited | Professional & scientific | 2022 |
| TYA Distributions Ltd | Wholesale & retail | 2026 |
| Tyercroft Limited | Administrative & support | 1987 |
| Tyler J Minot Group Ltd | Administrative & support | 2022 |
| Tylerandharding Ltd | Real estate | 2023 |
| Tylers Ride RTM Company Limited | Households | 2009 |
| Tylers Services Ltd | Administrative & support | 2023 |
| Tyli Ltd | Public administration | 2022 |
| Tyra Limited | Households | 2002 |
| Tyre Reclaim Limited | Other services | 2011 |
| Tythings (Howe Green) Management Company Limited | Households | 2005 |
| Tzafetta LLP | | 2010 |
| TZI Group Limited | Wholesale & retail | 2026 |
| U.S Soccer Scholarships Ltd. | Arts & recreation | 2014 |
| U.S Sports Scholarships Ltd | Arts & recreation | 2018 |
| Uaca International Ltd | Transport & logistics | 2021 |
| Uber Corporation Limited | Hospitality | 2010 |
| Uber Hair Solutions Limited | Other services | 2008 |
| Uber Hairdressing Limited | Other services | 2009 |
| Ubonrat Thai Therapy Ltd | Health & social care | 2026 |
| UCA Trans Ltd | Transport & logistics | 2019 |
| Ucgp Ltd | Administrative & support | 2015 |
| UCS Contracts Limited | Information & communication | 2000 |
| Ucyclewe Ltd | Financial services | 2025 |
| Udrea Trans Ltd | Transport & logistics | 2019 |
| UK & International Tax Advisers Limited | Extraterritorial | 2026 |
| UK Centre of Chinese Medicine Limited | Professional & scientific | 2023 |
| UK Coral Farm Limited | Agriculture & fishing | 2015 |
| UK Dogu Ltd | Construction | 2023 |
| UK Electrical Wholesale (Chelmsford) Limited | Wholesale & retail | 2011 |
| UK Electronic Components Limited | Manufacturing | 2005 |
| UK Mental Wellbeing Limited | Health & social care | 2016 |
| UK Pilates Enterprise Limited | Financial services | 2022 |
| UK Prestige Automobiles Limited | Wholesale & retail | 2013 |
| UK Properties Chowdhury Ltd | Real estate | 2024 |
| UK Property Answers Limited | Real estate | 2017 |
| UK Shandong Business Association Ltd | Other services | 2021 |
| UK Solutions Limited | Transport & logistics | 2015 |
| UK Sustainability Group Limited | Energy | 2021 |
| UK0577 Ltd | Wholesale & retail | 2023 |
| UKC Group Ltd | Financial services | 2024 |
| Ukdvdshop Limited | Wholesale & retail | 2023 |
| Ukmda Ltd | Financial services | 2025 |
| Uknowgroup Limited | Professional & scientific | 2020 |
| Ukpeptech Ltd | Administrative & support | 2025 |
| Ukscientificservices Limited | Professional & scientific | 2014 |
| ULG Management Limited | Financial services | 2007 |
| Ulmus Advisory Limited | Professional & scientific | 2021 |
| Ultima Design & Construction Ltd | Construction | 2025 |
| Ultima Group Holdings Ltd | Financial services | 2025 |
| Ultimate Dance NRG Limited | Arts & recreation | 2012 |
| Ultimate Financial Services Ltd | Professional & scientific | 2025 |
| Ultimate Lofts Ltd | Construction | 2017 |
| Ultimate Transport Services Limited | Other services | 2013 |
| Ultra Gloss Valeting Ltd | Administrative & support | 2026 |
| Ultra OPS Limited | Professional & scientific | 2022 |
| Ultraserve Group Limited | Administrative & support | 2024 |
| UMA Devi Limited | Health & social care | 2013 |
| Umanushi Limited | Financial services | 2007 |
| Umbrella Evolve Ltd | Education | 2023 |
| Umbrella Training and Employment Solutions Limited | Administrative & support | 2012 |
| Umbrix Ltd | Information & communication | 2023 |
| UME Garden Limited | Hospitality | 2021 |
| Unahia Ltd | Professional & scientific | 2021 |
| Uncensored CMO Limited | Administrative & support | 2021 |
| Undercover Turtles Ltd | Wholesale & retail | 2018 |
| Underpin Psychological Consultancy Ltd | Professional & scientific | 2018 |