| Totti Ltd | Hospitality | 2024 |
| Touch Marketing Activation Limited | Professional & scientific | 2012 |
| Tougoire Limited | Financial services | 2015 |
| Tourism Publishing Limited | Information & communication | 2002 |
| Tova London Catering & Events Limited | Hospitality | 2025 |
| Tovexa Ltd | Information & communication | 2025 |
| Toybox Cafe Ltd | Hospitality | 2021 |
| TP Building Ltd | Construction | 2009 |
| TPF 75 Limited | Real estate | 2002 |
| TPP MGT Ltd | Real estate | 2025 |
| TQ Associates Limited | Administrative & support | 2014 |
| TR Commercial Finance Ltd | Financial services | 2023 |
| TR Financial Ltd | Financial services | 2020 |
| Track Cars Ltd | Wholesale & retail | 2018 |
| Tradal Holdings Limited | Financial services | 2024 |
| Tradal Ltd | Real estate | 2022 |
| Trade 1 Limited | Other services | 2023 |
| Trade Bancorp Limited | Professional & scientific | 2024 |
| Trade Brothers Group Limited | Wholesale & retail | 2018 |
| Trade Finance Company (TFC) Ltd | Financial services | 2021 |
| Trade Finance Company International Limited | Financial services | 2025 |
| Trade Safeguard Limited | Information & communication | 2026 |
| Trademarcus Limited | Administrative & support | 2024 |
| Trainer Girl Productions Limited | Information & communication | 2014 |
| Trainkote Limited | Manufacturing | 2018 |
| Trakah Technologies Ltd | Information & communication | 2021 |
| Trancomm Limited | Information & communication | 2009 |
| Trand Medical Ltd | Health & social care | 2012 |
| Trans Country Estates Limited | Real estate | 1972 |
| Transblood Limited | Extraterritorial | 2011 |
| Transdrive Ltd | Transport & logistics | 2023 |
| Transferforce Ltd | Transport & logistics | 2024 |
| Transition Systems Ltd | Information & communication | 2016 |
| Transparent Energy Brokers Limited | Other services | 2024 |
| Transport Training Provider Ltd | Education | 2025 |
| Transvia Logistics Ltd | Transport & logistics | 2026 |
| Travel Genie Ltd | Administrative & support | 2019 |
| Travelads Limited | Professional & scientific | 2000 |
| Travelclassified Limited | Professional & scientific | 1999 |
| Travelclassified.Co.Uk Limited | Professional & scientific | 1999 |
| Travelclassified.Com Limited | Professional & scientific | 1999 |
| Travellanda Ltd | Administrative & support | 2010 |
| Travexor Ltd | Other services | 2025 |
| Trax Retail Ltd | Administrative & support | 2015 |
| Traxis Group Ltd | Information & communication | 2020 |
| Traybon Ltd | Professional & scientific | 2003 |
| Treasure Resource Ltd | Administrative & support | 2021 |
| Treatley Logistics LLP | | 2016 |
| Treatment Direct Limited | Health & social care | 2016 |
| Treetop Mews Management Limited | Households | 2012 |
| Trefoil Lodge RTM Company Limited | Households | 2025 |
| TREK4CEYLON Ltd | Arts & recreation | 2024 |
| Trendline Wholesale Limited | Wholesale & retail | 2024 |
| Trent Park Properties LLP | | 2008 |
| Trent Precast Concrete Limited | Construction | 2010 |
| Trent Reinforcements Ltd | Extraterritorial | 2010 |
| Trent SFS Limited | Manufacturing | 2017 |
| Trey Capital Ltd | Extraterritorial | 2022 |
| TRI Office 1 LLP | | 2026 |
| TRI Office Limited | Financial services | 2024 |
| TRI Office Manchester Limited | Real estate | 2024 |
| TRI Office Mosley Limited | Real estate | 2026 |
| TRI7 Focus 31 Limited | Real estate | 2019 |
| TRI7 Holdco Limited | Financial services | 2025 |
| TRI7 Limited | Real estate | 2021 |
| Triangle Management Company Limited | Administrative & support | 2003 |
| Tribute Deliveries LLP | | 2014 |
| Trilogy Solutions Limited | Other services | 2011 |
| Trim Apparel Ltd | Wholesale & retail | 2015 |
| Trinity Investments and Property Services Ltd | Construction | 2026 |
| Trinity Midlands Ltd | Real estate | 2026 |
| Trintex Solutions Ltd | Financial services | 2026 |
| Trio Food UK Limited | Hospitality | 2019 |
| Tripfolk Ltd | Information & communication | 2020 |
| Triple B Capital Ltd | Financial services | 2024 |
| Triple B Sports Ltd | Arts & recreation | 2024 |
| Triplethefun Ltd | Financial services | 2018 |
| Trippy FX Ltd | Arts & recreation | 2021 |
| Triton Investments Limited | Construction | 1973 |
| Triversity Ltd | Education | 2021 |
| Tron C R Ltd | Administrative & support | 2024 |
| Tron Car Rental Ltd | Administrative & support | 2015 |
| Tropa Elite Ltd | Information & communication | 2023 |
| Tropical Chef Ltd | Hospitality | 2010 |
| Trouv Chauffeur Limited | Transport & logistics | 2023 |
| Trowl Ltd | Wholesale & retail | 2020 |
| Trsv Limited | Wholesale & retail | 2025 |
| True Catering Engineering Ltd | Professional & scientific | 2016 |
| True Spark Solutions Ltd | Wholesale & retail | 2026 |
| True Story London Ltd | Arts & recreation | 2023 |
| True Tiger Limited | Arts & recreation | 2012 |
| Truesdales Media Limited | Information & communication | 2017 |
| Trugobrant UK Ltd | Other services | 2017 |
| Truman Estates Limited | Extraterritorial | 2012 |
| Trustful Building Ltd | Construction | 2020 |
| TS Trade Supplies Ltd | Wholesale & retail | 2026 |
| TSL Property Rentals Limited | Real estate | 2026 |
| Tsme Services Ltd | Other services | 2017 |
| TSP Management Limited | Administrative & support | 2024 |
| TTK Plant Limited | Administrative & support | 2021 |