| THE Three Putzes Investment Limited | Financial services | 2020 |
| THE Three Putzes Limited | Construction | 2020 |
| THE Tiny House Group Ltd | Manufacturing | 2025 |
| THE Topaz Mortgage Company Limited | Financial services | 2020 |
| THE Translation Shop Limited | Professional & scientific | 2015 |
| THE Twyst Hospitality Group Limited | Hospitality | 2025 |
| THE Ultimate Dog Walker Limited | Administrative & support | 2017 |
| THE Vaibs Group Ltd | Information & communication | 2016 |
| THE Vintage Studio Limited | Wholesale & retail | 2025 |
| THE Watch Force Limited | Wholesale & retail | 2014 |
| THE Whole Move Company Ltd | Administrative & support | 2004 |
| THE Woodhouse Group Holdings Ltd | Financial services | 2025 |
| THE Woodhouse Group Investments Ltd | Real estate | 2025 |
| THE Woof Lounge Ltd | Administrative & support | 2016 |
| THE Ying Group (USA) Limited | Professional & scientific | 2016 |
| Theatreland Hospitality Limited | Administrative & support | 2025 |
| Theela LS Management Limited | Professional & scientific | 2020 |
| Theela Properties Ltd | Real estate | 2020 |
| Theracell Advanced Biotechnology Ltd | Other services | 2012 |
| There and Then Limited | Real estate | 2010 |
| Thesupplytrain Ltd | Information & communication | 2019 |
| Thia Wellness & Support Ltd | Wholesale & retail | 2026 |
| Think Big Corporation Ltd | Administrative & support | 2025 |
| Thinktech Systems Limited | Information & communication | 2025 |
| Third GEN Limited | Wholesale & retail | 2013 |
| Thirteen Tite Street Freehold Limited | Other services | 2005 |
| Thirteen Tite Street RTM Company Limited | Administrative & support | 2006 |
| Thirty Eight Pembridge Villas Limited | Households | 1985 |
| This Colour Works Limited | Other services | 2020 |
| Thomas Properties (PSL) Limited | Real estate | 2004 |
| Thorndale Terrace Management Company Limited | Households | 2016 |
| Thornton Road Management Company Limited | Real estate | 1974 |
| Thorogood Audio Visual Limited | Manufacturing | 2015 |
| Thorp Investment Limited | Real estate | 2021 |
| Thoughtsee Limited | Other services | 2021 |
| Three Bears Vets Ltd | Professional & scientific | 2018 |
| Three Half Acres Limited | Information & communication | 2022 |
| Three Willows Care Home Ltd | Health & social care | 2017 |
| Threesixdesign Ltd | Professional & scientific | 2020 |
| Thunderbolt & Franklin Ltd | Wholesale & retail | 2024 |
| Tianyuan Trading Limited | Wholesale & retail | 2025 |
| TIC Holdings Limited | Real estate | 2021 |
| Tide + Seek Ltd | Wholesale & retail | 2022 |
| Tigf Ltd | Wholesale & retail | 2026 |
| Tiller Limited | Real estate | 2004 |
| TIM Stoney Music Limited | Information & communication | 2024 |
| Timber and Trading Agency (International) Limited | Administrative & support | 1985 |
| Timcon Consulting Limited | Professional & scientific | 2022 |
| TIME2CARE (Barnet) Ltd | Health & social care | 2014 |
| Tinderpoint (UK) Ltd | Administrative & support | 2002 |
| TIPIS4HIRE Ltd | Administrative & support | 2006 |
| Titan FX Ltd | Other services | 2019 |
| Tithe Close Management Company Limited | Households | 2003 |
| TJR Music Ltd | Arts & recreation | 2020 |
| TKA Film Ltd | Arts & recreation | 2024 |
| TLT Management Services Limited | Other services | 2024 |
| TNB Productions Limited | Information & communication | 2025 |
| Toesai Limited | Professional & scientific | 2022 |
| Together LDN Limited | Professional & scientific | 2016 |
| Tolfree Properties Limited | | 1969 |
| TOM Walsh Music Ltd | Arts & recreation | 2019 |
| Tomori GB Ltd | Construction | 2018 |
| Tonbul & Herons Legal Services Ltd | Professional & scientific | 2023 |
| Toni Landscaping Ltd | Administrative & support | 2025 |
| Top Note Management Limited | Professional & scientific | 2019 |
| Toppssales Ltd | Wholesale & retail | 2025 |
| Topstream Logistics Ltd | Transport & logistics | 2025 |
| Tora Touring LLP | | 2017 |
| Tornbrook Limited | Hospitality | 2004 |
| Totally Driven Limited | Administrative & support | 2026 |
| Toto Properties Limited | Administrative & support | 2012 |
| Totteridge Holdings Limited | Real estate | 2025 |
| Towp Ltd | Wholesale & retail | 2021 |
| Towp Sport Ltd | Wholesale & retail | 2020 |
| Toy TAP LLP | | 2019 |
| TP Interior Solutions Limited | Construction | 2007 |
| TR Installations Ltd | Construction | 2017 |
| Trade Staffing Solutions Ltd | Administrative & support | 2024 |
| Trading Office Limited | Information & communication | 2018 |
| Trail Technology Ltd | Information & communication | 2017 |
| Training and Promotion Hub Limited | Education | 2022 |
| Tranquility Luxury Travel Ltd | Administrative & support | 2012 |
| Transarca Limited | Mining & quarrying | 2003 |
| Transformation Exterior Cleaning Limited | Administrative & support | 2024 |
| Translogistics & Expedition Limited | Wholesale & retail | 2002 |
| Transmission Parts Online Limited | Wholesale & retail | 2021 |
| Transportation Investment Limited | Financial services | 2006 |
| Transworldcom Limited | Information & communication | 2011 |
| Travel Industry Connect Limited | Other services | 2017 |
| Travel UK Information Limited | Transport & logistics | 2013 |
| Travel With Kitts Limited | Administrative & support | 2013 |
| Treasured Favours of London Limited | Manufacturing | 2018 |
| Tregubenko Legal Services Limited | Financial services | 2017 |
| Trendal Properties Limited | Wholesale & retail | 1999 |
| Trendlease Property Management Limited | Households | 1991 |
| Trendy Trainers International Limited | Wholesale & retail | 2002 |
| Tres Casas Ltd | Real estate | 2022 |
| Triada Properties Ltd | Real estate | 2021 |
| Triangle Midco Limited | Administrative & support | 2021 |
| Trigggle Ltd | Professional & scientific | 2022 |