| Tile Hill Housing Limited | Administrative & support | 2024 |
| Tile Hill Interim & Executive Limited | Administrative & support | 2016 |
| TOI Design Ltd | Professional & scientific | 2019 |
| Tonerone Ltd | Wholesale & retail | 2020 |
| Topgear Autocentre Letchworth Limited | Wholesale & retail | 2022 |
| Torpak Limited | Other services | 2009 |
| Torque Racing Services Limited | Wholesale & retail | 2013 |
| Total Location Confidence Limited | Administrative & support | 2007 |
| Total Solutions Technology Ltd | Manufacturing | 2021 |
| Townsend Light & Design Ltd | Other services | 2024 |
| Tpas (UK) Limited | Wholesale & retail | 1996 |
| Track Geometry Limited | Manufacturing | 2024 |
| Trafalgar Cases Limited | Manufacturing | 1968 |
| Training Beauty & Beyond Ltd | Education | 2021 |
| Trancis Limited | Hospitality | 2021 |
| Trancis Shop Limited | Wholesale & retail | 2021 |
| Transformers Construction Ltd | Construction | 2025 |
| Transit MAN Ltd | Transport & logistics | 2025 |
| Transmoor Limited | Real estate | 1987 |
| Transporter AL Ltd | Transport & logistics | 2025 |
| Treadaway Plumbing and Heating Limited | Construction | 2011 |
| Trespass Magazine Limited | Extraterritorial | 2009 |
| Triple SIX Motorcycles Ltd | Wholesale & retail | 2024 |
| Triumvere Developments Limited | Real estate | 2024 |
| Troika Consultancy Ltd | Administrative & support | 2019 |
| Troika Property Services Ltd | Real estate | 2019 |
| Trueman Bidco Limited | Administrative & support | 2020 |
| Trueman Holdco Limited | Administrative & support | 2017 |
| Trueman Midco Limited | Administrative & support | 2020 |
| Trueman Parent a Limited | Manufacturing | 2017 |
| Tryka L.E.D. Limited | Manufacturing | 2002 |
| Tryka LED SPD Limited | Manufacturing | 2020 |
| TSG Landscapes Ltd | Administrative & support | 2026 |
| TTM Consultancy Services Limited | Manufacturing | 1997 |
| Tudor Park (1985) Management Co. Limited | Households | 1985 |
| Tudor Park (West) Management Co. Limited | Households | 1984 |
| Tuluc Consulting Ltd | Professional & scientific | 2016 |
| Turleyway Limited | Administrative & support | 2019 |
| Turquoise 111 Ltd | Hospitality | 2025 |
| Tutti Frutti Clothing Ltd | Manufacturing | 2022 |
| TWE Contracting Ltd | Construction | 2025 |
| Twitchell Ltd | Information & communication | 2020 |
| Tyre Sales (Birmingham) Limited | Extraterritorial | 1971 |
| U H Y Hacker Young (East) Limited | Administrative & support | 2013 |
| UB Letchworth Ltd | Other services | 2020 |
| UC21 Limited | Information & communication | 2024 |
| UH Assets Ltd | Real estate | 2024 |
| UHY East CF Limited | Professional & scientific | 2020 |
| UHY WKH Limited | Professional & scientific | 2014 |
| UK Drummers Limited | Education | 2012 |
| UK ERP Support Limited | Information & communication | 2013 |
| Ultrasupport Services Limited | Other services | 2018 |
| Ultravolt SPV1 Limited | Construction | 2023 |
| Ultravolt SPV3 Limited | Energy | 2024 |
| Uncaged Ventures Limited | Information & communication | 2015 |
| Union 10 Design LLP | | 2013 |
| Union Talent Limited | Administrative & support | 2025 |
| Unity Search Limited | Administrative & support | 2023 |
| Universal One Global Holdings Ltd | Professional & scientific | 2025 |
| Unruly Kitchen Ltd | Hospitality | 2026 |
| Untangled Music Ltd | Information & communication | 2021 |
| Urban Grind Trading Limited | Wholesale & retail | 2026 |
| V. S. Truckin' Ltd | Transport & logistics | 2019 |
| Vade Mecum Consulting Limited | Information & communication | 2002 |
| Valabio Solutions Limited | Professional & scientific | 2024 |
| Valet-Glym Limited | Extraterritorial | 2000 |
| Vanguard Universal Ltd | Professional & scientific | 2016 |
| Vennskap Ltd | Hospitality | 1995 |
| Venture 78 Commercial Ltd | Real estate | 2024 |
| Venture 78 Ltd | Real estate | 2024 |
| Venture 78 Management Company Limited | Households | 2024 |
| Vermason Limited | Professional & scientific | 1979 |
| Vihet Limited | Professional & scientific | 2021 |
| Viju Psychology Practice Ltd | Health & social care | 2018 |
| VIK Consultancy Services Limited | Information & communication | 2012 |
| Vincent Van Hire Limited | Wholesale & retail | 1983 |
| VIR Productions Limited | Information & communication | 2015 |
| Viridia Ltd | Manufacturing | 2020 |
| Vista Building and Engineering Limited | Construction | 2013 |
| Visual Language Ltd | Arts & recreation | 2026 |
| Vital Electronics Limited | Wholesale & retail | 2021 |
| Vmtw Associates Ltd | Other services | 2022 |
| Voice PA Limited | Administrative & support | 2026 |
| Voltaic Group Ltd | Professional & scientific | 2021 |
| Vortex Elevators Ltd | Manufacturing | 2024 |
| VP Electro-Tech Ltd | Construction | 2023 |
| Vutie Beets Limited | Hospitality | 2017 |
| Walkwel Limited | Health & social care | 2014 |
| Wallace Books Limited | Wholesale & retail | 2009 |
| Wallace Holdco Ltd | Financial services | 2021 |
| Walnut & Squirrel Property Limited | Real estate | 2025 |
| Walsworth Limited | Professional & scientific | 1997 |
| Wards Property Services Ltd | Construction | 2023 |
| Warmth Artists Ltd | Professional & scientific | 2020 |
| Wasteflux Ltd | Water & waste | 2026 |
| Waterstone Capital Limited | Real estate | 2017 |
| Waterstone Construction Limited | Construction | 2018 |
| Watsmith Flat Management Company Limited | Households | 1978 |
| Waybury Group Limited | Real estate | 2022 |
| Waybury Ltd | Construction | 2019 |