| TLA Wickford Limited | Administrative & support | 2015 |
| Tleh Consulting Limited | Financial services | 2019 |
| Tleh Leeds I Limited | Construction | 2023 |
| Tleh SS1 Limited | Construction | 2024 |
| Tmvmt CIC | Administrative & support | 2021 |
| TN Films Ltd | Information & communication | 2019 |
| Toal Associates Ltd | Other services | 2023 |
| Tobias Consulting Ltd | Professional & scientific | 2021 |
| Todalogistics Ltd | Wholesale & retail | 2026 |
| Toga Enterprises Ltd | Manufacturing | 2026 |
| Together! 2012 C.I.C. | Education | 2013 |
| Toiv Limited | Construction | 2008 |
| TOM Brignell Limited | Administrative & support | 2003 |
| TOM Business Development & Consultancy Ltd | Professional & scientific | 2019 |
| TOM Chick Pictures Limited | Information & communication | 2017 |
| TOM Cotton Limited | Other services | 2020 |
| Tombo Limited | Professional & scientific | 1998 |
| Tomex Holdings Ltd | Financial services | 2026 |
| Tommys International PVT Ltd | Transport & logistics | 2025 |
| Toms Farm (Maldon) Limited | Construction | 2025 |
| Tona Homes Limited | Real estate | 2009 |
| Tony Alan Asset Management Limited | Real estate | 2024 |
| Tony Nick Classic Mercedes Ltd | Administrative & support | 2026 |
| Toof Limited | Administrative & support | 2022 |
| Toot Toot Cars Ltd | Wholesale & retail | 2021 |
| Top Gear Transport Limited | Administrative & support | 2018 |
| Top Selection Limited | Wholesale & retail | 2000 |
| Top World Ltd | Information & communication | 2018 |
| TOP1DESIGN Ltd | Wholesale & retail | 2026 |
| Topbuilders Limited | Construction | 2012 |
| Topshelf Group Limited | Construction | 1966 |
| Topshelf Investments Limited | Construction | 1961 |
| Toptron Limited | Administrative & support | 1997 |
| TOR Networks Ltd | Information & communication | 2016 |
| Torcida Visinie Ltd | Construction | 2015 |
| Total Track Limited | Arts & recreation | 2004 |
| Total Wellness Solutions Ltd | Health & social care | 2019 |
| Totally Enterprises Limited | Hospitality | 2015 |
| Totally Trade Direct Limited | Wholesale & retail | 2010 |
| Touchstone Media Group Limited | Administrative & support | 2010 |
| Toukaneyes Limited | Information & communication | 2011 |
| Toukanlabs Limited | Administrative & support | 2014 |
| Tourhq Limited | Information & communication | 2022 |
| Toury Ltd | Professional & scientific | 2024 |
| TOW and Shift Ltd | Administrative & support | 2024 |
| Tower Estates Gravesend Ltd | Real estate | 2012 |
| Tower Group Developments Ltd | Real estate | 2024 |
| Tower Parade Consult and Design Limited | Professional & scientific | 2017 |
| Tower Properties Investments Ltd | Real estate | 2024 |
| Towermead Enterprises (Holdings) Limited | Real estate | 1993 |
| Towermead Enterprises Limited | Real estate | 1989 |
| Toxic Web Ltd | Information & communication | 2023 |
| Toycon UK Ltd | Wholesale & retail | 2015 |
| Toyexim Limited | Wholesale & retail | 2002 |
| TPF Analytics Ltd | Information & communication | 2023 |
| Trabes Ltd | Households | 2022 |
| Tracey Price Limited | Professional & scientific | 2023 |
| Trackside Management P Limited | Professional & scientific | 2025 |
| Trade and Financial Services (2023) Ltd | Professional & scientific | 2023 |
| Trade Business Ltd | Wholesale & retail | 2024 |
| Trademaster Electrical Ltd | Construction | 2024 |
| Tramley Limited | Professional & scientific | 2015 |
| Tranlowe Ltd | Real estate | 2009 |
| Tranquility Beauty (UK) Ltd | Other services | 2012 |
| Transbuilding Service Limited | Manufacturing | 2003 |
| Transflow (Scotland) Limited | Professional & scientific | 2002 |
| Transflow Industrial Services Limited | Administrative & support | 1994 |
| Transport Limited | Professional & scientific | 2019 |
| Transthermal Management Services Limited | Construction | 1993 |
| Transuk Global Logistics Limited | Transport & logistics | 2018 |
| TRC Living Limited | Real estate | 2020 |
| Trcs Holdings Limited | Financial services | 2018 |
| Trendscout AI Limited | Information & communication | 2025 |
| Trendy Clicks Limited | Wholesale & retail | 2025 |
| Trent Family Services Ltd | Health & social care | 2022 |
| Trialexpress Limited | | 1988 |
| Triangle Electrical Services Ltd | Construction | 2007 |
| Tricky Evolution Ltd | Administrative & support | 2020 |
| Trickytrade Ltd | Construction | 2019 |
| Trilark Limited | Real estate | 2019 |
| Trimag Ltd | Hospitality | 2026 |
| Trinilark Limited | Hospitality | 2026 |
| Trinity Classic Autos Ltd | Wholesale & retail | 2019 |
| Trinity Palmer Holdings Limited | Financial services | 2023 |
| Trinity Residential Property Ltd | Real estate | 2026 |
| Tripletletsacquisitions Limited | Extraterritorial | 2024 |
| Triptailor Travel Limited | Administrative & support | 2024 |
| Triumph Real Estate Ltd | Real estate | 2020 |
| TRU Community Limited | Information & communication | 2018 |
| Truflow Ventilation Ltd | Construction | 2024 |
| Truly Great Things Ltd | Wholesale & retail | 2020 |
| Truss IT Limited | Administrative & support | 2007 |
| Truss Property Ltd | Real estate | 2020 |
| Ttblc Limited | Arts & recreation | 2024 |
| Tuco Consulting Limited | Other services | 2018 |
| Tugby and Tugby Surveyors Limited | Professional & scientific | 2004 |
| Tugby Limited | Construction | 2007 |
| Tula London Limited | Real estate | 2017 |
| Tulip Care One Limited | Health & social care | 2006 |
| Tulip Care Two Limited | Administrative & support | 2008 |