| Terry Milner Ltd. | Administrative & support | 2022 |
| Terry Moore Ltd | Wholesale & retail | 2015 |
| Terulie Ltd | Construction | 2019 |
| Terzetto Limited | Construction | 2009 |
| Terzi Property Ltd | Real estate | 2026 |
| Tescher.Co Ltd | Wholesale & retail | 2023 |
| Tescominication Ltd | Transport & logistics | 2026 |
| Tesedi UK Limited | Information & communication | 2006 |
| Tesla Business Services Ltd | Professional & scientific | 2016 |
| Tesla Energy & Maintenance Limited | Wholesale & retail | 2025 |
| Teslary Ltd | Transport & logistics | 2026 |
| Teslift Ltd | Manufacturing | 2009 |
| Tess Ward Limited | Hospitality | 2012 |
| Tessa Burnard Ltd | Health & social care | 2022 |
| Tessellate Labs Limited | Information & communication | 2025 |
| Tessmukuze Limited | Health & social care | 2020 |
| Test Consulting Limited | Professional & scientific | 2009 |
| Test Crew Limited | Information & communication | 2025 |
| Test Director Limited | Information & communication | 2011 |
| Test LAD Ltd | Information & communication | 2026 |
| Test Meter Group Limited | Wholesale & retail | 2005 |
| Testbed Leeds Ltd | Arts & recreation | 2020 |
| Testingpro Limited | Professional & scientific | 2018 |
| Testoptima Consulting Limited | Information & communication | 2023 |
| Testra Technologies Ltd | Extraterritorial | 2011 |
| Testset Ltd | Information & communication | 2014 |
| Tetley Family Holdings Limited | Financial services | 2024 |
| Tetley Hall Development Ltd | Real estate | 2020 |
| Tetley Hall Investment Ltd | Real estate | 2020 |
| Teto Ltd | Transport & logistics | 2021 |
| Tetra Steel Corps Ltd | Manufacturing | 2025 |
| Tetra Tech Environment Planning Transport Limited | Professional & scientific | 1995 |
| Tetra Tech Group Limited | Professional & scientific | 2008 |
| Tetra Tech Limited | Professional & scientific | 1985 |
| Tetra Tech Management Services Limited | Professional & scientific | 2003 |
| Tetra Tech Planning Limited | Professional & scientific | 2004 |
| Tetra Tech UK Consulting Group Limited | Professional & scientific | 1984 |
| Tetris Property Solutions Ltd | Construction | 2025 |
| Tetrodaxol GB Limited | Information & communication | 2025 |
| Teulu Property Investments Limited | Real estate | 2024 |
| Teuton | Financial services | 2021 |
| Teva Trans Ltd | Other services | 2022 |
| Tewit Well Court Management Limited | Households | 1985 |
| Texelate Limited | Professional & scientific | 2010 |
| TEXT2SAVE Limited | Professional & scientific | 2005 |
| TEXT4ALOAN Limited | Professional & scientific | 2004 |
| TEXT4LOANS Limited | Professional & scientific | 2004 |
| Textile Laboratory Services Limited | Professional & scientific | 2015 |
| Textile Mania Limited | Wholesale & retail | 2020 |
| Textloans Limited | Professional & scientific | 2004 |
| Textpigeon Ltd | Wholesale & retail | 2010 |
| TF Corporation Limited | Wholesale & retail | 2007 |
| TF Global Executive Search Ltd | Administrative & support | 2018 |
| TF Productions Ltd | Arts & recreation | 2018 |
| Tfalc Limited | Administrative & support | 2008 |
| Tfas Compliance Services Limited | Financial services | 2000 |
| Tfas Enterprises Ltd | Financial services | 2021 |
| Tfas Group Holdings Limited | Financial services | 2017 |
| Tfas Wealth Ltd | Professional & scientific | 2021 |
| Tfast Logistics Limited | Transport & logistics | 2020 |
| TFD Developments Ltd | Construction | 2025 |
| TFE97 Ltd | Health & social care | 2022 |
| TFF Care Ltd | Health & social care | 2026 |
| Tfil Solutions Limited | Administrative & support | 2024 |
| TFM Agricultural Construction Limited | Financial services | 2022 |
| Tfrj Properties Limited | Real estate | 2025 |
| TFS MED UK Limited | Information & communication | 2010 |
| TFS Property Management Limited | Real estate | 2022 |
| Tfsc Global Trading Limited | Manufacturing | 2024 |
| TG Demolition & Strip Outs Ltd | Construction | 2024 |
| TGC Recruitment Ltd | Administrative & support | 2019 |
| Tgcl 2024 Limited | Extraterritorial | 2019 |
| TGH Estates (UK) Ltd | Real estate | 2019 |
| TGK Solutions Limited | Administrative & support | 2025 |
| Tgks Accountancy Limited | Professional & scientific | 2012 |
| Tglc Investments Ltd | Real estate | 2024 |
| Tglc Ltd | Hospitality | 2020 |
| TGM Properties Ltd | Real estate | 2018 |
| Tgrr Limited | Construction | 2013 |
| TGV Supplies Ltd | Wholesale & retail | 2018 |
| TGW (Holdings) Limited | Professional & scientific | 2002 |
| TH Inter Ltd | Extraterritorial | 2022 |
| TH Nails & Beauty Limited | Other services | 2020 |
| TH Traders Limited | Wholesale & retail | 2026 |
| TH3 SFS Ltd | Manufacturing | 2024 |
| Thadle Ltd | Wholesale & retail | 2025 |
| Thai Garden Cafe 2 Limited | Hospitality | 2015 |
| Thai Garden Cafe Limited | Hospitality | 2011 |
| Thai Marketplace Limited | Wholesale & retail | 2019 |
| Thai Patthana Ltd | Education | 2018 |
| Thai Time Therapy Ltd | Health & social care | 2025 |
| Thaiology Massage Limited | Health & social care | 2026 |
| Thaitan Ltd | Information & communication | 2019 |
| Thakra Mart Limited | Wholesale & retail | 2026 |
| Thala Enterprises | Financial services | 2022 |
| Thalamai Ltd | Information & communication | 2024 |
| Thali Outlet Limited | Extraterritorial | 2008 |
| Thaluka Ltd | Wholesale & retail | 2023 |
| Thalunar Holdings Ltd | Manufacturing | 2025 |
| Thames Reach Limited | Real estate | 2024 |