| Tru-Flo Services Limited | Construction | 2024 |
| Trubi Ltd | Transport & logistics | 2022 |
| Trudevelop Ltd | Professional & scientific | 2025 |
| True Carpentry Limited | Construction | 2014 |
| True Exposure Studio Ltd | Professional & scientific | 2026 |
| True Function Ninja Training Ground Limited | Education | 2017 |
| True Horizon Construction Ltd | Construction | 2025 |
| True Turtle Surf Co Limited | Wholesale & retail | 2023 |
| Truly Clean Limited | Administrative & support | 2016 |
| Trust-Worthy Home Maintenance Ltd | Construction | 2011 |
| Trusted Counsel Limited | Professional & scientific | 2018 |
| Trusted Surgery Turkey Ltd | Professional & scientific | 2026 |
| Trustroad Services Ltd | Transport & logistics | 2026 |
| Trut Ltd | Hospitality | 2016 |
| Trutech Solutions Ltd | Information & communication | 2024 |
| Truth Whisky Ltd | Manufacturing | 2023 |
| Truvia Ltd | Transport & logistics | 2025 |
| TRV Plumbing and Heating Ltd | Construction | 2019 |
| Tryco Group Management Limited | Real estate | 2021 |
| Tscleanz Limited | Administrative & support | 2026 |
| TSG Aviation Limited | Transport & logistics | 2012 |
| Tshirt Studio Ltd | Wholesale & retail | 2002 |
| TSJ Catering Ltd | Hospitality | 2024 |
| TSL Trans Ltd | Transport & logistics | 2018 |
| TSM Distributions Ltd | Transport & logistics | 2019 |
| Tsquared Courier’S Ltd | Transport & logistics | 2022 |
| Tsunami Martial Arts LLP | | 2017 |
| TTS Training Services Ltd | Information & communication | 2013 |
| Tucango Limited | Transport & logistics | 2026 |
| Tudor-Vap Ltd | Wholesale & retail | 2025 |
| Tuga Pastries Limited | Manufacturing | 2015 |
| Tuga Spray Ltd | Wholesale & retail | 2020 |
| Tuhon Ltd | Extraterritorial | 2021 |
| TUK Tuck Ltd | Hospitality | 2015 |
| Tukuna Solutions Ltd | Information & communication | 2017 |
| Tulip and Lily Care Ltd | Health & social care | 2026 |
| Tumble Tots Newcastle LLP | | 2025 |
| Tumble Tots Winchmore Hill LLP | | 2025 |
| Tuning Software Factory Ltd | Wholesale & retail | 2021 |
| Tunley Properties Limited | Real estate | 1965 |
| Tunnel Vision Projects Ltd | Real estate | 2021 |
| Turnball Mews Management Limited | Households | 1998 |
| Turnbull Close Management Company Limited | Households | 2024 |
| Turner Investments Group Global Limited | Financial services | 2026 |
| Turner Investments Group Limited | Financial services | 2020 |
| Turners Irrigation Services Ltd | Water & waste | 2023 |
| Turning Japanese Ltd | Professional & scientific | 2025 |
| Turnkey Timber Frame Ltd | Construction | 2025 |
| Turtle Construction Limited | Construction | 2021 |
| Turtle Financial Solutions Limited | Professional & scientific | 2016 |
| Turtle Groundwork Ltd | Construction | 2022 |
| Turtle Oak Construction Ltd | Construction | 2010 |
| TV Golf Limited | Administrative & support | 2025 |
| Twaa-Uk Ltd | Wholesale & retail | 2022 |
| TWC Home Group Ltd | Manufacturing | 2012 |
| Tweenbridge Limited | Professional & scientific | 2026 |
| Twelve 09 Construction Limited | Construction | 2020 |
| Twhf Educational Services Limited | Education | 2019 |
| Twhf Technical Services Limited | Wholesale & retail | 2019 |
| Twigolet Ltd | Real estate | 2025 |
| Twigplace Limited | | 1988 |
| Twigworth Development Limited | Real estate | 2006 |
| Twilighteventplanners Limited | Arts & recreation | 2025 |
| Twineham Business Solutions Ltd | Professional & scientific | 2022 |
| Twitchmusic Ltd | Information & communication | 2024 |
| TWITCHMUSIC.2 Ltd | Information & communication | 2026 |
| Two Sparks Properties Ltd | Real estate | 2018 |
| Two-Mei Recordings Ltd | Information & communication | 2025 |
| Twyco Ltd | Financial services | 2024 |
| Twyford Projects Ltd | Construction | 2021 |
| TY Financial Services Ltd | Financial services | 2019 |
| Tyco Electronics Corby Limited | Extraterritorial | 1970 |
| Tyco Electronics UK Holdings Ltd | Professional & scientific | 2007 |
| Tyer and Company Limited | Manufacturing | 2022 |
| Tyler Plastics Processing Limited | Manufacturing | 1990 |
| Tylers Building Services Ltd | Construction | 2022 |
| Tylkowski Ltd | Transport & logistics | 2017 |
| Tynta Ltd | Wholesale & retail | 2025 |
| Tyres NOW Ltd | Wholesale & retail | 2021 |
| Tyrrell Investments Limited | Professional & scientific | 2003 |
| Tytus Trans Limited | Wholesale & retail | 2019 |
| TZ Essentials Ltd | Wholesale & retail | 2025 |
| Tzac Limited | Health & social care | 2022 |
| Tzcatalog Ltd | Wholesale & retail | 2025 |
| U & R Electrical Ltd | Construction | 2022 |
| U C B Home Loans Corporation Limited | Financial services | 1972 |
| U O M Pharma Ltd | Wholesale & retail | 2021 |
| U.D General Services Limited | Real estate | 2024 |
| U.K.Ickers LLP | | 2019 |
| U.P.S Systems PLC | Information & communication | 1993 |
| UA Crombey Ltd | Wholesale & retail | 2025 |
| UA Slee Ltd | Wholesale & retail | 2025 |
| UA Swindon Ltd | Wholesale & retail | 2024 |
| Uamtech Ltd | Information & communication | 2021 |
| UAV Test Pilots Ltd | Other services | 2013 |
| Ubhi Builders Ltd | Construction | 2015 |
| Ubique Consultants Ltd | Professional & scientific | 2011 |
| UBR Plumbing Ltd | Construction | 2025 |
| Ubresiri Ltd | Health & social care | 2019 |
| UC Delicious Menu Ltd | Extraterritorial | 2023 |