| Toughglaze (UK) Limited | Manufacturing | 1996 |
| Toughglaze PLC | Professional & scientific | 1993 |
| Toughscaff London Limited | Professional & scientific | 2015 |
| Tour Safe Group Ltd. | Arts & recreation | 2023 |
| Tour Safe Ltd | Arts & recreation | 2022 |
| Tour Van Golf Ltd | Wholesale & retail | 2019 |
| Tower Tax Limited | Professional & scientific | 2004 |
| Towerstone Accountants Ltd | Professional & scientific | 2022 |
| Town & Country Management Limited | Real estate | 2003 |
| Town & Country Property Group Ltd | Real estate | 2019 |
| Town and Country Residential Limited | Real estate | 1998 |
| Town Autos Limited | Wholesale & retail | 2014 |
| Town Meadow Residents Association Limited | Households | 1979 |
| TP Drones Ltd | Professional & scientific | 2025 |
| TP Inspection Ltd | Professional & scientific | 2023 |
| TPI Fencing & Gardens Ltd | Administrative & support | 2024 |
| TPT Medical Ltd | Health & social care | 2017 |
| Tqual AB UK Ltd | Education | 2025 |
| TR Carpentry & Building Services Ltd | Construction | 2025 |
| TR Landscapes Ltd | Administrative & support | 2025 |
| TRA Haulage Ltd | Transport & logistics | 2017 |
| Trace Films Ltd | Information & communication | 2022 |
| Traction Power Advice Limited | Professional & scientific | 2015 |
| Tracy Fensome Coach Limited | Other services | 2018 |
| Trade Build Network Ltd | Information & communication | 2026 |
| Trade Department Limited | Real estate | 2014 |
| Trade Tints Ltd | Wholesale & retail | 2011 |
| Tradeline Recruitment Ltd | Administrative & support | 2007 |
| Trademark Bricklaying Limited | Construction | 2019 |
| Tradespot International Ltd | Wholesale & retail | 2024 |
| Tradewind Properties Ltd | Real estate | 2024 |
| Traditional Aegean Food Supplies Ltd | Wholesale & retail | 2023 |
| Trained AI Ltd | Information & communication | 2026 |
| Training Elements Limited | Extraterritorial | 2005 |
| Training, Design & Consultancy (Td&C) Limited | Professional & scientific | 2005 |
| Trakkidoo Health Ltd | Professional & scientific | 2026 |
| Tranquil Properties Ltd | Real estate | 2025 |
| Tranquila Investments Limited | Extraterritorial | 2005 |
| Trans Costas Ltd | Transport & logistics | 2013 |
| Trans Danmo Ltd | Transport & logistics | 2023 |
| Transform Finance Solutions Limited | Professional & scientific | 2025 |
| Transforming Dreams Group Keynsham Limited | Real estate | 2026 |
| Transforming Dreams Group Limited | Real estate | 2025 |
| Transition Cycles Limited | Wholesale & retail | 2008 |
| Transmission Dynamics Limited | Wholesale & retail | 2012 |
| Transport & Logistics Group Limited | Wholesale & retail | 2022 |
| Transport Carrier Services Limited | Transport & logistics | 2003 |
| Transport DS Limited | Transport & logistics | 2025 |
| Transport Gaby Ltd | Manufacturing | 2024 |
| Trapezaki Villa Holidays Limited | Administrative & support | 2012 |
| Travel 24 Ltd | Transport & logistics | 2021 |
| Travel Health Training Limited | Health & social care | 2004 |
| Travel Kids Ltd | Wholesale & retail | 2026 |
| Travelset Diaries Ltd | Administrative & support | 2026 |
| Travelwideflights Ltd | Administrative & support | 2019 |
| Trayfenn Ltd | Professional & scientific | 2017 |
| Traynor & SON Electrical Ltd | Construction | 2010 |
| TRE Fratelli Brothers Limited | Hospitality | 2009 |
| Treacle Mine PUB and Restaurant Company Limited | Hospitality | 2017 |
| Treasure Bakes Ltd | Hospitality | 2021 |
| Treasure Tress Limited | Health & social care | 2014 |
| Treasure Vault Inc Ltd | Wholesale & retail | 2024 |
| Treasured Mind Ltd | Other services | 2023 |
| Treatment Link Ltd | Health & social care | 2018 |
| Treble Engineering Limited | Manufacturing | 2023 |
| Treble Services Limited | Construction | 2004 |
| Tredwell Success Ltd | Professional & scientific | 2020 |
| Tree Specific Ltd | Administrative & support | 2012 |
| Tree Strategy & Coaching Limited | Professional & scientific | 2025 |
| Tregargus Management Company Limited | Households | 1985 |
| Trelawny Wealth Management Ltd | Professional & scientific | 2020 |
| Trendhiv Ltd | Administrative & support | 2025 |
| Trevor Bacon Consulting Ltd | Construction | 2018 |
| Trevor Limited | Extraterritorial | 2008 |
| Trewoofe Cottages Limited | Real estate | 2022 |
| TRH Estate Ltd | Real estate | 2021 |
| TRH Group Ltd | Information & communication | 2018 |
| Triangular Limited | Real estate | 2004 |
| Tribal Climbing Ltd | Administrative & support | 2010 |
| Tribe Services Limited | Extraterritorial | 2007 |
| Trick Tech Ltd | Arts & recreation | 2012 |
| Tricky 73 Limited | Professional & scientific | 2024 |
| Trident Properties (Bedford) Ltd | Real estate | 2026 |
| Trigon Capital Ltd | Real estate | 2020 |
| Trim & Gleam Limited | Construction | 2026 |
| Trimax Consultants Limited | Professional & scientific | 2024 |
| Trimmings Unlimited Dormant Ltd | Manufacturing | 2014 |
| Trimmings Unlimited Ltd | Wholesale & retail | 2019 |
| Trimtab Consulting Ltd | Information & communication | 2025 |
| Trinity Care Group Ltd | Health & social care | 2021 |
| Trinity Care Sheerness Ltd | Health & social care | 2024 |
| Trinity Contracts Ltd | Construction | 2014 |
| Trinity Investments and Properties Limited | Real estate | 2022 |
| Trinity Living World Ltd | Wholesale & retail | 2026 |
| Trinity Realty Management Ltd | Real estate | 2024 |
| Trinity Stairways Limited | Manufacturing | 2025 |
| Trio KAY Supported Housing C.I.C. | Health & social care | 2024 |
| Trio-H Homes Ltd | Real estate | 2025 |
| Trip Electrical Limited | Construction | 2017 |
| Trip Electrical Services Ltd | Construction | 2024 |