| Trevilo Ltd | Professional & scientific | 2020 |
| Trevone Properties Limited | Real estate | 2015 |
| Trevor Ellis Consulting Limited | Professional & scientific | 2004 |
| Trezlas Ltd | Information & communication | 2025 |
| TRH Electricial Ltd | Construction | 2026 |
| Triangle Interiors Limited | Wholesale & retail | 2002 |
| Tribus Clean Energy Limited | Professional & scientific | 2018 |
| Trident Infomedia Group Ltd | Information & communication | 2024 |
| Trifecta Trends Limited | Wholesale & retail | 2024 |
| Trifle Tech Ltd | Information & communication | 2023 |
| Tring Group Ltd | Manufacturing | 2025 |
| Tringmotion Limited | Wholesale & retail | 2014 |
| Trinity Fuel Ltd | Wholesale & retail | 2023 |
| Trinity Peaks Limited | Other services | 2013 |
| Triosel UK Packaging Limited | Manufacturing | 2026 |
| Triple C Properties Ltd | Real estate | 2025 |
| Triple E Healthcare Ltd | Administrative & support | 2021 |
| Triple T Medics Limited | Health & social care | 2015 |
| Tripple Diamond Limited | Health & social care | 2022 |
| Trirha Limited | Real estate | 2026 |
| Triveni CIC | Education | 2023 |
| Trivoxtech Limited | Information & communication | 2025 |
| TRM Auto Solutions Limited | Wholesale & retail | 2025 |
| TRM Property Services Limited | Construction | 2025 |
| TRN Consultants Ltd | Administrative & support | 2018 |
| Trojan Roofing Limited | Construction | 1996 |
| Trudy Ross Developments Limited | Real estate | 2013 |
| True Source Trading Limited | Wholesale & retail | 2026 |
| Trueaura Care Ltd | Administrative & support | 2025 |
| Trusted Business Adviser Limited | Professional & scientific | 2025 |
| Trusted Business Advisor Limited | Professional & scientific | 2019 |
| Trustedge Accountancy Ltd | Professional & scientific | 2024 |
| TRY Center Ltd | Other services | 2023 |
| TRY Comms Ltd | Other services | 2023 |
| TS Brickwork Ltd | Construction | 2018 |
| TS Bucks Limited | Transport & logistics | 2023 |
| TS Range Services Ltd | Professional & scientific | 2018 |
| TS Space Ltd | Real estate | 2019 |
| TS Survey Ltd | Professional & scientific | 2026 |
| TS Welding and Fabrication Limited | Manufacturing | 2022 |
| Tsab Accounting & Bookkeeping Limited | Professional & scientific | 2026 |
| Tsekov Decorations Ltd | Construction | 2018 |
| TSF Solutions Limited | Information & communication | 2016 |
| TSH Trustees Ltd | Administrative & support | 2023 |
| Tskgasservices Ltd | Construction | 2020 |
| TSM Capital Ltd | Financial services | 2020 |
| Tsss Distribution Ltd | Wholesale & retail | 2021 |
| Tsss Trading Ltd | Wholesale & retail | 2020 |
| TT Consult Ltd | Professional & scientific | 2026 |
| Ttak Ltd. | Health & social care | 2013 |
| Tttechsales Ltd | Wholesale & retail | 2023 |
| TTZ Fitness Ltd | Arts & recreation | 2020 |
| Tubb Investment and Development Limited | Real estate | 2016 |
| Tubb Investment Limited | Real estate | 2024 |
| Tubb Investment London Limited | Real estate | 2025 |
| Tubervale Property Management Limited | Professional & scientific | 2002 |
| Tuckett Farm Services Limited | Administrative & support | 2001 |
| Tucsen Photonics UK Ltd | Professional & scientific | 2024 |
| Tudor Lettings Ltd | Real estate | 2022 |
| Tudor-Casian Ltd | Manufacturing | 2022 |
| Tudora Ltd | Wholesale & retail | 2026 |
| Tullah Associates Ltd | Real estate | 2022 |
| Tunari Limited | Information & communication | 2015 |
| Turbine Recon Centre Limited | Professional & scientific | 2015 |
| Turlough Consultancy Ltd | Information & communication | 2015 |
| Turpin Trading Limited | Professional & scientific | 2025 |
| TV Camera Limited | Information & communication | 2009 |
| TVC Conversions Ltd | Wholesale & retail | 2026 |
| TW Memorials Ltd | Wholesale & retail | 2026 |
| Twainforge Limited | Wholesale & retail | 1981 |
| Twbd Property Limited | Construction | 2026 |
| Twelftree Electrical Services Limited | Construction | 2024 |
| Twelve Kites Ltd | Information & communication | 2016 |
| Twentyfirst Century Justice CIC | Professional & scientific | 2026 |
| Twinlock (Ireland) Limited | Extraterritorial | 1971 |
| Twinztransport Ltd | Wholesale & retail | 2023 |
| Twisted Note Records Ltd | Arts & recreation | 2011 |
| TWK Ltd | Transport & logistics | 2011 |
| Two 7 Developments Ltd | Construction | 2021 |
| Two Beaumont Crescent Management Ltd | Households | 2020 |
| Two Oaks Landscapes Limited | Administrative & support | 2019 |
| Twsr Motorsport Limited | Wholesale & retail | 2021 |
| Twymarsh Developments Ltd | Construction | 2006 |
| Tyndall Property Management Limited | Households | 2023 |
| Type Pro Limited | Education | 2016 |
| Tyrone Andrew Bennett Ltd | Construction | 2025 |
| Tytella Limited | Real estate | 1986 |
| Tythrop White Limited | Construction | 2012 |
| Tzuriel GT Limited | Real estate | 2026 |
| Tzuriel Limited | Real estate | 2026 |
| U&B Consultants Limited | Information & communication | 2013 |
| Ubanatu Ewuzie Medical Supplies Limited | Health & social care | 2022 |
| Ubanatu Ewuzie Property Investment Limited | Real estate | 2023 |
| UBF Construction Limited | Construction | 2025 |
| UBF Industrial Ltd | Real estate | 2015 |
| Ubiserve Ltd | Other services | 2023 |
| Ubuyudo.Com Ltd | Wholesale & retail | 2015 |
| Uchvic & Associates Ltd | Health & social care | 2019 |
| Uhsnow Ltd | Manufacturing | 2020 |
| UIK Properties Limited | Real estate | 2023 |