| Tibbetts Estates Holdings Limited | Wholesale & retail | 2025 |
| Tibbetts Estates Limited | Real estate | 2022 |
| Tibbetts Fasteners Limited | Financial services | 2004 |
| Tibbetts Global Limited | Wholesale & retail | 2025 |
| Tibbetts Holdings Limited | Wholesale & retail | 2022 |
| Tickle Sports International Limited | Professional & scientific | 2024 |
| Tidy Touch Cleaning Services Ltd | Administrative & support | 2023 |
| Tier One Connect Limited | Professional & scientific | 2019 |
| Tileform U.K. Limited | Real estate | 2005 |
| Tiling Excellence (Oxon) Limited | Construction | 2014 |
| TIM OX16 Limited | Hospitality | 2025 |
| TIM Spittles Limited | Information & communication | 2015 |
| Timbertrace Ltd | Professional & scientific | 2020 |
| Time for Impact Ltd | Professional & scientific | 2023 |
| Timeless Drives Ltd | Wholesale & retail | 2025 |
| Timeless Stitches Embroidery Ltd | Wholesale & retail | 2024 |
| Tingan Limited | Information & communication | 1999 |
| Tingling Ltd | Wholesale & retail | 2025 |
| Tinkers Barn Estate Ltd | Real estate | 2020 |
| Tinsan Motorsport Limited | Arts & recreation | 2024 |
| Tiosk Limited | Wholesale & retail | 2013 |
| Tipedge Limited | Real estate | 1984 |
| TIR Developments Limited | Real estate | 2026 |
| Titanium Legacy Ltd | Professional & scientific | 2021 |
| TJG Solutions Limited | Information & communication | 2019 |
| TKA Fashion Ltd | Wholesale & retail | 2025 |
| TKA Rentals Limited | Real estate | 2021 |
| Tkrc Limited | Construction | 2021 |
| TKS Limited | Real estate | 1991 |
| TLM Property Maintenance Ltd | Construction | 2023 |
| Tmaskills Ltd | Education | 2025 |
| TMT Advisory and Services Limited | Professional & scientific | 2016 |
| TN4 Homes Ltd | Real estate | 2021 |
| Tndungu Ltd | Public administration | 2016 |
| TNN Express Limited | Transport & logistics | 2017 |
| Toast Design Consultancy Limited | Arts & recreation | 2002 |
| Toast Plugins Limited | Professional & scientific | 2020 |
| Tobey Evans Lighting Ltd | Professional & scientific | 2021 |
| Toby Electronics Limited | Manufacturing | 1983 |
| Toftwood Investment Ltd | Real estate | 2020 |
| Toftwood Real Estate Ltd | Construction | 2017 |
| Toland Management Services Ltd | Professional & scientific | 2019 |
| TOM Carlton Farms Limited | Real estate | 1978 |
| TOM Negus Tree Care Ltd | Agriculture & fishing | 2025 |
| TOM Righton Investments Ltd | Financial services | 2022 |
| Toma Jamona Ltd | Manufacturing | 2022 |
| Tomex Ltd | Wholesale & retail | 2025 |
| Tomita U.K. Limited | Wholesale & retail | 1991 |
| Tommy Logistics Ltd | Transport & logistics | 2017 |
| Tom’S Diner Limited | Hospitality | 2019 |
| Tonal Motivation Ltd | Arts & recreation | 2026 |
| Tonc Limited | Construction | 2025 |
| Tooth Transport Ltd | Professional & scientific | 2025 |
| Top Kids Accessories Limited | Wholesale & retail | 2016 |
| Top Priority Emergency Cleans UK Ltd | Administrative & support | 2023 |
| Top Tyres Banbury Ltd | Wholesale & retail | 2026 |
| Topclass BIZ Support Limited | Administrative & support | 2023 |
| Topeka Logistics Holdings Ltd | Financial services | 2025 |
| Topeka Logistics Ltd | Financial services | 2016 |
| Topeka Logistics Trustees Limited | Financial services | 2025 |
| Tormatrix Limited | Information & communication | 2005 |
| Total Balance Nutrition Ltd | Other services | 2025 |
| Total Facilities Ltd | Construction | 2004 |
| Total Image Banbury Ltd | Other services | 2015 |
| Total Laundry Ltd | Other services | 2025 |
| Total Mobile Tyres & Vehicle Recovery Ltd | Wholesale & retail | 2025 |
| Total Paint Solutions Ltd | Wholesale & retail | 2019 |
| Total Turfcare Limited | Administrative & support | 2022 |
| Tour DE Trigs | Arts & recreation | 2012 |
| Townley Stone Holdings Limited | | 1981 |
| Townsend Farming Limited | Agriculture & fishing | 2005 |
| TP Knotweed Solutions Ltd | Administrative & support | 2018 |
| TP Steelwork Ltd | Manufacturing | 2003 |
| TPB Productions Ltd | Arts & recreation | 2022 |
| TPS Developing Organisations Limited | Administrative & support | 2002 |
| Tradalhko Limited | Professional & scientific | 2014 |
| Tradepresence Ltd | Information & communication | 2026 |
| Trans-Fwd Limited | Transport & logistics | 2015 |
| Transdar Ltd | Transport & logistics | 2016 |
| Transformational Results Limited | Professional & scientific | 2017 |
| Transformative AI Holdings Ltd | Information & communication | 2025 |
| Travel Planners UK Ltd | Administrative & support | 2016 |
| Travel With US Limited | Wholesale & retail | 2014 |
| TRC Media Ltd | Information & communication | 2024 |
| Treatbell Limited | Households | 1992 |
| Trends UK Limited | Wholesale & retail | 2002 |
| Trendtidy Ltd | Wholesale & retail | 2022 |
| Treverry Farms Holding Limited | Professional & scientific | 2008 |
| Treverry Farms Limited | Agriculture & fishing | 1988 |
| Trew 2 U Ltd | Wholesale & retail | 2025 |
| Tribe Media Limited | Extraterritorial | 2009 |
| Tribox Ltd | Education | 2022 |
| Tribu Group Limited | Administrative & support | 2012 |
| Trinders Barbershop Ltd | Other services | 2020 |
| Trinley Development Limited | Real estate | 2021 |
| Tripple 'K' Accounting Services Ltd | Professional & scientific | 2015 |
| Tromans Property Holdings Ltd | Real estate | 2022 |
| Trousdale Limited | Manufacturing | 1998 |
| Trovare Services Limited | Administrative & support | 2021 |
| TRP Europe Limited | Professional & scientific | 2025 |