| Tpjs Advisory Limited | Administrative & support | 2025 |
| TPP Global Services Ltd | Administrative & support | 2019 |
| Tracey Jane's Photography & Prints Ltd | Professional & scientific | 2024 |
| Tractamus Ltd | Construction | 2017 |
| Transcule Limited | Administrative & support | 2014 |
| Translead Limited | Real estate | 2000 |
| Transparent Hotels Ltd | Hospitality | 2013 |
| Transpolis Global Europe Ltd | Professional & scientific | 2012 |
| Transworld International Freight & Trade Limited | Administrative & support | 2012 |
| Travaleur Limited | Administrative & support | 2015 |
| Travel Nation Limited | Administrative & support | 2001 |
| Travel Software Development Limited | Information & communication | 1988 |
| Travelbrands Limited | Administrative & support | 2004 |
| Travelco Limited | Administrative & support | 1992 |
| Travelling Beauty Limited | Other services | 2017 |
| Travellocal Ltd | Administrative & support | 2010 |
| Travelwise Limited | Administrative & support | 1980 |
| Treadstone Luxury Packaging Ltd | Information & communication | 1998 |
| Tredray Electrical Contracting Ltd | Construction | 2016 |
| Treetops Hideouts Ltd | Hospitality | 2023 |
| Trego Developments Ltd | Construction | 2021 |
| Treviso Garden Limited | Hospitality | 2023 |
| Treviso Italian Limited | Hospitality | 2025 |
| Treximo Ltd | Administrative & support | 2014 |
| TRG Consulting Ltd | Information & communication | 2022 |
| Triangle Hire Ltd | Administrative & support | 2022 |
| Tribe DCL Ltd | Professional & scientific | 2017 |
| Tricker Holdings Ltd | Financial services | 2025 |
| Triflorum Collations Ltd | Information & communication | 2016 |
| Trigon Fire Safety Ltd | Professional & scientific | 2019 |
| Trimble Productions Limited | Information & communication | 2020 |
| Trinder Partnership LLP | | 2018 |
| Trinity 365 Care Ltd | Administrative & support | 2016 |
| Trinity Fashion Limited | Wholesale & retail | 2017 |
| Triode Capital UK Ltd | Financial services | 2026 |
| Triple O Corporate Services Limited | Professional & scientific | 2017 |
| Trophy Pet Foods (North East) Limited | Wholesale & retail | 2010 |
| Tropical Skies Limited | Extraterritorial | 2005 |
| Tropical Sky Hotels Limited | Extraterritorial | 2007 |
| Tropical Sky Limited | Administrative & support | 2005 |
| Trse Services Ltd | Administrative & support | 2023 |
| Truck & Trailer Assist Ltd | Wholesale & retail | 2024 |
| Trudgeon Roberts Limited | Construction | 2013 |
| True Gents (Richmond) Ltd | Other services | 2024 |
| True Grit Cleaning Company Ltd | Administrative & support | 2025 |
| True Ingredients Co. Ltd | Information & communication | 2008 |
| True Travel Limited | Administrative & support | 2013 |
| Truly Bloomin' Gardens Limited | Other services | 2013 |
| Trust Fulfilment 3D Design Ltd | Wholesale & retail | 2021 |
| Trustportal Solutions Limited | Information & communication | 2017 |
| TS9 Creative Limited | Information & communication | 2018 |
| TT Salisbury Research Limited | Professional & scientific | 2019 |
| Ttwsc Ltd | Real estate | 2024 |
| Tuch Design Limited | Arts & recreation | 1988 |
| Tudor House Richmond Limited | Real estate | 2014 |
| Tuer Holdings Ltd | Financial services | 2024 |
| Tukuypaj Life Coach School Ltd | Education | 2022 |
| Tukuypaj Ltd | Administrative & support | 2018 |
| Tunnel Legal Consultancy Ltd | Real estate | 2019 |
| Tunstall Court (Resident Association) Limited | Households | 1965 |
| Tunstall Court Limited | Households | 1996 |
| Tunstall Meat Company Limited | Wholesale & retail | 2017 |
| Tura 2018 Ltd | Hospitality | 2018 |
| Turavia International Holidays Limited | Professional & scientific | 1973 |
| Turkey Mill Estate Limited | Real estate | 2017 |
| Turkey Mill Investments Limited | Real estate | 1997 |
| Turkish Bite Food Ltd | Hospitality | 2026 |
| Turner Pursuit Limited | Real estate | 2022 |
| Turning Tables Consulting Ltd | Education | 2022 |
| Turvey Westgarth LLP | | 2018 |
| Tutu Pikin Limited | Manufacturing | 2018 |
| TVL Europe | Financial services | 2005 |
| TVL Travel Limited | Financial services | 2007 |
| Tvwd Ltd | Arts & recreation | 2025 |
| TW10PRAC Ltd | Health & social care | 2023 |
| TW10PROP Ltd | Real estate | 2023 |
| TW9 Maintenance Ltd | Construction | 2022 |
| Twcog LLP | | 2016 |
| Twelfth MAN Solutions Limited | Professional & scientific | 2013 |
| Twenty One Twenty Seven Investments Limited | Real estate | 2022 |
| Twenty Third C Ltd | Information & communication | 2016 |
| Twenty Third C Technology Limited | Information & communication | 2021 |
| TWENTY7 Bike Travel Ltd. | Arts & recreation | 2022 |
| Twickenham Company Services Limited | Professional & scientific | 1996 |
| Twickenham Property Limited | Real estate | 1998 |
| Twickenham Youth Theatre Ltd | Education | 2025 |
| Twin Spark Finance Limited | Administrative & support | 2022 |
| Two Dales Bakery Limited | Wholesale & retail | 2018 |
| Two Ears Ltd | Information & communication | 2002 |
| Two Little Boys Limited | Wholesale & retail | 2002 |
| Two Monkeys Productions Limited | Information & communication | 2020 |
| Two Sevens Communications Limited | Professional & scientific | 2012 |
| Twsa Holding Ltd | Financial services | 2022 |
| Tyne View Holdings Limited | Financial services | 2018 |
| Tyneside Leisure World Limited | Extraterritorial | 2012 |
| Typecase Limited | Manufacturing | 2004 |
| Tyrrell Hatton Golf Limited | Other services | 2013 |
| Tyvenic Limited | Information & communication | 2015 |
| U-Lead Limited | Education | 2012 |
| UHD Commercial Finance Limited | Financial services | 2023 |