| Trendnest Ltd | Wholesale & retail | 2024 |
| Trendytor Ltd | Wholesale & retail | 2025 |
| Tresmontana Ltd | Professional & scientific | 2022 |
| Tretis Limited | Administrative & support | 2017 |
| Tretonia Property Ltd | Construction | 2022 |
| Tretonia UK Ltd | Construction | 2018 |
| Tretonia UK2 Ltd | Construction | 2023 |
| Trett Investment Holdings Limited | Financial services | 2023 |
| Tretts of Tyneside Ltd | Transport & logistics | 2022 |
| Trevella Jobs Ltd | Administrative & support | 2021 |
| Trevelyan Advisory Ltd | Professional & scientific | 2021 |
| Trevor Brown Piping Ltd | Construction | 2015 |
| Trevor Wilkinson International Limited | Financial services | 1993 |
| TRH Investments Ltd | Real estate | 2025 |
| TRI Construction Group Limited | Construction | 2026 |
| TRI Construction Holdings Limited | Construction | 2018 |
| TRI Construction Limited | Construction | 2015 |
| TRI Properties Limited | Construction | 2016 |
| Tribal Cycle Ltd | Arts & recreation | 2024 |
| Tribe Solutions Limited | Professional & scientific | 2023 |
| Tricomm Housing (Holdings) Limited | Construction | 2001 |
| Tricomm Housing Limited | Construction | 2001 |
| Trident Building & Services Solutions Ltd | Construction | 2019 |
| Trident Dynamics Ltd | Professional & scientific | 2014 |
| Trident Gold Ltd | Construction | 2024 |
| Trident Renovations Ltd | Construction | 2019 |
| Trigger Flow Ltd | Information & communication | 2025 |
| Trillians Rockbar Ltd | Hospitality | 2014 |
| Trillionaire Broading Productions Ltd | Information & communication | 2022 |
| Trilogy 1 (Saltwell) Management Company Limited | Real estate | 2015 |
| Trimmen Gosforth Ltd | Other services | 2025 |
| Trimmen Ltd | Other services | 2021 |
| Trims for HIM (Killingworth) Limited | Other services | 2012 |
| Trinamic Engineering Ltd | Manufacturing | 2017 |
| Trinder Limited | Real estate | 2020 |
| Trinder Property Company Limited | Real estate | 2019 |
| Trinity Academy Newcastle | Education | 2013 |
| Trinity Centre Limited | Administrative & support | 2008 |
| Trinity Energy and Building Services Limited | Construction | 2021 |
| Trinity Engineering and Building Services Limited | Professional & scientific | 2014 |
| Trinity Gardens Associates Limited | Financial services | 2011 |
| Trinity Gardens Developments PLC | Construction | 2001 |
| Trinity Ophthalmic Services Ltd | Health & social care | 2023 |
| Trinity Post 16 Solutions Limited | Education | 2015 |
| Trinity Sakthi Private Ltd | Wholesale & retail | 2024 |
| Trinity Workforce Limited | Administrative & support | 2021 |
| Trinity Youth Association | Education | 1998 |
| Trinityworkforce Healthcare Limited | Administrative & support | 2022 |
| Trins Limited | Real estate | 2019 |
| Tripiq Systems Limited | Information & communication | 2014 |
| Triple 8 Cabs Ltd | Transport & logistics | 2025 |
| Triple Cush Industries Ltd. | Professional & scientific | 2022 |
| Triple Eight Motor Company Limited | Wholesale & retail | 2006 |
| Triple Four Holdings Limited | Financial services | 2026 |
| Triple Hands Agro Foods Enterprises Limited | Wholesale & retail | 2024 |
| Triple HT Limited | Wholesale & retail | 2026 |
| Triple-K Integrated Services Ltd | Information & communication | 2019 |
| Tripler Trading Ltd | Wholesale & retail | 2024 |
| Tripnovel Limited | Hospitality | 1990 |
| Triumph Cleaning Services Ltd | Households | 2024 |
| Trivela Media Limited | Arts & recreation | 2016 |
| Triwillhospo Ltd | Professional & scientific | 2026 |
| TRL9 Limited | Professional & scientific | 2015 |
| Trojan Decking Ltd | Construction | 2015 |
| Trojan Electrical Ltd | Construction | 2021 |
| Tromploy Estates Limited | Hospitality | 2010 |
| Troo Health Care Limited | Wholesale & retail | 2009 |
| Trovare Industries Ltd | Water & waste | 2021 |
| TRR Coaching Ltd | Education | 2025 |
| Trubuild North East Ltd | Construction | 2013 |
| True Bond Brickwork Ltd | Construction | 2026 |
| True Citizen Ltd | Professional & scientific | 2025 |
| True Innovations & Design (UK) Limited | Extraterritorial | 2018 |
| True North Civils Ltd | Construction | 2025 |
| True North Construction Limited | Construction | 2019 |
| True North Electrical Services Ltd | Construction | 2023 |
| True North People Solutions Limited | Administrative & support | 2025 |
| True North Renovations Ltd | Construction | 2025 |
| True North Tyres Ltd | Wholesale & retail | 2025 |
| True Potential Administration LLP | | 2019 |
| True Potential Adviser Services LLP | | 2007 |
| True Potential Group Limited | Professional & scientific | 2015 |
| True Potential Holdings Limited | Financial services | 2016 |
| True Potential Investments LLP | | 2010 |
| True Potential LLP | | 2012 |
| True Potential Nominee Limited | Administrative & support | 2018 |
| True Potential Trustee Company Limited | Financial services | 2013 |
| True Potential Wealth Management LLP | | 2010 |
| True Solicitors LLP | | 2012 |
| True Tyne Engineering Limited | Manufacturing | 2002 |
| True-Homes Group Ltd | Real estate | 2019 |
| Truebo Educational Consultancy Ltd | Professional & scientific | 2023 |
| Trueman Creative Group Ltd | Wholesale & retail | 2025 |
| Truequote Ltd | Information & communication | 2015 |
| Truly Madly Events Ltd | Hospitality | 2023 |
| Truly Madly Pizza Limited | Hospitality | 2020 |
| Truong Estate Ltd | Real estate | 2023 |
| Truss IT Holdings Limited | Financial services | 2025 |
| Trust Red Limited | Wholesale & retail | 2015 |
| Trusted Business Partner Limited | Administrative & support | 2018 |