| Tptm Limited | Real estate | 2025 |
| TR Consulting and Advisory Limited | Construction | 2019 |
| Traders Plus Ltd | Wholesale & retail | 2012 |
| Traffex (UK) Ltd | Professional & scientific | 2021 |
| Traidenis Ltd | Transport & logistics | 2022 |
| Traingogy Limited | Education | 2015 |
| Trandafir@ Ltd | Construction | 2024 |
| Trans Air Services Limited | Wholesale & retail | 1988 |
| Trans Impex Ltd | Transport & logistics | 2017 |
| Transvis Ltd | Transport & logistics | 2017 |
| Treadstone Design & Build Limited | Construction | 2023 |
| Treasure Tots PRE School Limited | Education | 2016 |
| Trevor MAY Contractors Limited | Construction | 1999 |
| Trevor Place Limited | Construction | 2023 |
| Triangle Ventures Limited | Professional & scientific | 2024 |
| Trifort Health Limited | Education | 2025 |
| Trimart Investments Limited | Real estate | 2025 |
| Trimart Properties Limited | Real estate | 2017 |
| Trimming Shop 007 Limited | Wholesale & retail | 2014 |
| Trimming Shop Holding Ltd | Financial services | 2021 |
| Trimming Shop Property Limited | Real estate | 2021 |
| Trinity Homes Group Ltd | Real estate | 2024 |
| Trinity Manor Limited | Real estate | 2025 |
| Trinity Square (NW9) Management Company Limited | Households | 2015 |
| Trinova Wholesale Ltd | Wholesale & retail | 2026 |
| Triple a Property Investments Ltd | Real estate | 2019 |
| Triple Digits Limited | Other services | 2015 |
| Triple PAY Ltd | Professional & scientific | 2018 |
| TRJ Construction Ltd | Construction | 2012 |
| Trubridge Films Ltd | Information & communication | 2012 |
| True Haven Properties Ltd | Real estate | 2022 |
| True Hearing Limited | Health & social care | 2017 |
| True Shepherd Clinical Services Limited | Health & social care | 2020 |
| Trutec Services Limited | Information & communication | 2016 |
| Truth Construction Ltd. | Construction | 2015 |
| TS Performance Limited | Transport & logistics | 2021 |
| TS1PROPERTY Ltd | Real estate | 2023 |
| TST Painting Ltd | Construction | 2026 |
| Tsuki Group Ltd | Manufacturing | 2026 |
| Ttechspcs Limited | Wholesale & retail | 2025 |
| TTP Swim School Limited | Education | 2015 |
| Tttb Limited | Wholesale & retail | 2019 |
| Tulip Cafe Limited | Hospitality | 2026 |
| Tulip Tree Richmond Ltd | Hospitality | 2021 |
| Tuneright Motors Limited | Wholesale & retail | 2020 |
| Turhan's Bristol Ltd | Other services | 2025 |
| Turners Court Cheshunt Limited | Households | 1998 |
| Turners Hill Autocare Limited | Wholesale & retail | 2025 |
| Turners Hill Xpress Ltd | Wholesale & retail | 2025 |
| Turquaz Leisure Park Limited | Real estate | 2026 |
| Tuskers Brands Limited | Wholesale & retail | 2025 |
| TV AV Installations Limited | Information & communication | 2009 |
| TV AV Warehouse Limited | Information & communication | 2007 |
| Twilson Consultants Ltd | Information & communication | 2022 |
| Twin Top Ltd | Wholesale & retail | 2022 |
| Twin TUB Collective Ltd | Information & communication | 2013 |
| Twinvest Holdings Ltd | Construction | 2022 |
| Two Brass Monkeys Limited | Manufacturing | 2019 |
| Twocans Entertainment Ltd | Information & communication | 2025 |
| Twumson Limited | Other services | 2015 |
| TYS Investments Limited | Real estate | 2026 |
| Tzicu Ltd | Transport & logistics | 2022 |
| U&E Medical Ltd | Health & social care | 2022 |
| U&G Cooling Ltd | Professional & scientific | 2024 |
| U.K. Funeral Directors Limited | Other services | 2010 |
| Uclicktobuy Ltd | Wholesale & retail | 2024 |
| UCS Property Management Limited | Real estate | 2011 |
| Ucur Properties Limited | Real estate | 2019 |
| Ugly Betty's Ltd | Other services | 2019 |
| Ugur Cleaning Ltd | Administrative & support | 2020 |
| UK Autobridge Ltd | Wholesale & retail | 2021 |
| UK Black Wolf Ltd | Transport & logistics | 2026 |
| UK Card Trading Co Limited | Wholesale & retail | 2026 |
| UK City Signs Ltd | Professional & scientific | 2020 |
| UK Ekin Ltd | Other services | 2026 |
| UK Itech Ltd | Information & communication | 2020 |
| UK Nergis Ltd | Construction | 2021 |
| UK Truck Properties Limited | Real estate | 2020 |
| UK Truckcentre Limited | Financial services | 2019 |
| UK Truckholdings Limited | Financial services | 2019 |
| UK Truckparts Limited | Wholesale & retail | 2013 |
| UK Truckrepairs Limited | Wholesale & retail | 2017 |
| UKA Contractors Ltd | Construction | 2023 |
| UKA Investments Ltd | Real estate | 2025 |
| Ultimate Dimension Ltd | Information & communication | 2022 |
| Ultimate Model Corporation Limited | Professional & scientific | 1996 |
| Ultra Trans Ltd | Transport & logistics | 2020 |
| Unakite Coaching Ltd | Professional & scientific | 2020 |
| Unbiased Financial Planning Ltd. | Financial services | 2014 |
| Undercut Flipz Ltd | Wholesale & retail | 2025 |
| Unicon Consultancy Ltd | Professional & scientific | 2019 |
| Unigrade Investments Limited | Wholesale & retail | 2025 |
| Unik Drink Ltd | Other services | 2013 |
| Unique Bakery Ltd | Wholesale & retail | 2025 |
| Unique Home (London) Limited | Wholesale & retail | 2015 |
| Universal Homes Group Limited | Real estate | 2024 |
| Universally Yours Limited | Administrative & support | 2016 |
| Univerzone Limited | Information & communication | 2025 |
| Upbourne Limited | Real estate | 2022 |
| Upgrade Property Services Ltd | Construction | 2015 |