| Trigri House Limited | Wholesale & retail | 2020 |
| Trill Clothing Ltd | Wholesale & retail | 2025 |
| Trilosworld Ltd | Wholesale & retail | 2024 |
| Trimurti Estates Limited | Real estate | 2023 |
| Trinary Care Professionals Limited | Administrative & support | 2022 |
| Trinary Training Solutions Limited | Administrative & support | 2024 |
| Trinity Bridge (Stratford Upon Avon) Management Company Limited | Households | 2003 |
| Trinity Court (NO. 1) Management Company Limited | Households | 1996 |
| Trinity Court (NO. 2) Management Company Limited | Households | 1997 |
| Trinity Court (Southwark) Freehold Limited | Households | 2004 |
| Trinity Court (Southwark) Residents Company Ltd | Households | 1997 |
| Trinity Distributions Ltd | Wholesale & retail | 2022 |
| Trinity Fields Management Company Limited | Households | 2011 |
| Trinity Gardens (Oxton) Management Company Limited | Households | 2008 |
| Trinity View Management Limited | Households | 2015 |
| Trinton Services Limited | Other services | 2024 |
| Trio Pizzeria Limited | Hospitality | 2013 |
| Trip Manager Ltd | Extraterritorial | 1999 |
| Tripabooking Ltd | Professional & scientific | 2026 |
| Triple I (Kent) Limited | Hospitality | 2019 |
| Triple L Care Ltd | Health & social care | 2023 |
| Triple O Investments Limited | Real estate | 2022 |
| Triple Trading Packaging Limited | Manufacturing | 2026 |
| Tripleb’Sservices Limited | Households | 2020 |
| Triplem Homes Ltd | Real estate | 2023 |
| Triplerrr Autos Ltd | Wholesale & retail | 2025 |
| Triplets Exterior Cleaning Ltd | Administrative & support | 2023 |
| Tripod Asset Management Limited | Real estate | 2003 |
| Trisha Ofuasia Consultancy Ltd | Administrative & support | 2023 |
| Trishna Healthcare Ltd | Health & social care | 2025 |
| Tristan Property (Sittingbourne) Ltd | Construction | 2018 |
| Tristan Property Trust Ltd | Real estate | 2013 |
| Triton Financial Solutions Limited | Professional & scientific | 2008 |
| Triumph Builders Limited | Construction | 2015 |
| Trivalo Limited | Administrative & support | 2026 |
| Trivarna Consulting Limited | Information & communication | 2025 |
| TRJ Square Limited | Real estate | 2024 |
| TRK FIX Ltd | Other services | 2025 |
| Trochair Limited | Real estate | 1930 |
| Troodos Developments Limited | Real estate | 2025 |
| Trophyplanet Ltd | Wholesale & retail | 2015 |
| Tropic Skincare Limited | Manufacturing | 2011 |
| Troveseek Ltd | Wholesale & retail | 2025 |
| TRR Equine Limited | Administrative & support | 2009 |
| Trucraft Repairs Ltd | Manufacturing | 2024 |
| Trudyhelps Limited | Health & social care | 2022 |
| True Colourz Property Services Limited | Construction | 2018 |
| True Form Building Services Ltd | Construction | 2025 |
| True North Connection Ltd | Arts & recreation | 2026 |
| True Organics London Ltd | Manufacturing | 2021 |
| True Vine Apostolic Ministry Limited | Other services | 2022 |
| Truenorth UK Investments Ltd | Real estate | 2025 |
| Truffiere Limited | Agriculture & fishing | 2018 |
| Trulli Food UK Ltd | Wholesale & retail | 2016 |
| Trus Developers Ltd | Real estate | 2025 |
| Trust OUR Move Ltd | Transport & logistics | 2023 |
| Trusted Brickwork & Developments Limited | Construction | 2019 |
| Trustwell Care Ltd | Health & social care | 2025 |
| Truth and Lucky Limited | Administrative & support | 2026 |
| Truth Bar LDN (Croydon) Ltd | Hospitality | 2024 |
| Truuli Limited | Real estate | 2018 |
| TS & JB Property Limited | Real estate | 2022 |
| TS Rand Limited | Professional & scientific | 2022 |
| TS Security Solutions Ltd | Administrative & support | 2019 |
| Tsarina Social Work Ltd | Health & social care | 2021 |
| Tsayetan Fotbea Ltd. | Health & social care | 2010 |
| Tsetoulidis Geo-Solutions Limited | Administrative & support | 2022 |
| TSP Holdings Inc Ltd | Real estate | 2023 |
| TSR Associates Limited | Construction | 2023 |
| TSR Building & Maintenance Ltd | Other services | 2020 |
| TSR Holdings Ltd | Real estate | 2024 |
| Tsrm Limited | Professional & scientific | 2022 |
| Tsseroplus SVG Ltd | Professional & scientific | 2024 |
| Tsuyoki Holdings Ltd | Financial services | 2022 |
| TT Professional Services Limited | Professional & scientific | 2018 |
| Ttbatchelor Limited | Hospitality | 2023 |
| TTG Construction Ltd | Construction | 2012 |
| Ttpxlx Ltd | Construction | 2025 |
| TTS Hotel Service Limited | Administrative & support | 2021 |
| Tubind UK Ltd | Manufacturing | 2024 |
| Tudor Chest Limited | Education | 2023 |
| Tudor Court (Victoria Road) Management Company Limited | Households | 2008 |
| Tudor Court Ealing Limited | Households | 2011 |
| Tudor Hall (Camberley) Management Company Limited | Households | 1994 |
| Tudor House (Windlesham) Management Company Limited | Households | 2006 |
| Tudor Lodge Management Company Limited | Households | 1988 |
| Tudorform Limited | Households | 1997 |
| Tuff Leadership Training UK Ltd | Professional & scientific | 2024 |
| Tuftech Solutions UK Limited | Information & communication | 2023 |
| Tuhao Property Ltd | Real estate | 2024 |
| Tuitionology Ltd | Education | 2025 |
| Tulba Construction Ltd | Construction | 2026 |
| Tully Construction Limited | Construction | 2010 |
| Tulyam-Gv Ltd | Real estate | 2021 |
| Tuman Catering Ltd | Hospitality | 2013 |
| Tunbridge Wells Retreat Management Limited | Households | 2020 |
| Tune Harbour Ltd | Arts & recreation | 2024 |
| Tunnel Light Books and Holdings Ltd | Manufacturing | 2017 |
| Tural Limited | Hospitality | 2016 |
| Turan Barbers Ltd | Other services | 2016 |