| TP Health Limited | Health & social care | 2006 |
| TP Sprays Limited | Wholesale & retail | 2019 |
| TPA Electrical Ltd | Construction | 2021 |
| TPC Golf Ltd | Hospitality | 2026 |
| TPH Trading Limited | Administrative & support | 2025 |
| TPL Ballerina Ltd | Information & communication | 2024 |
| TPL Falling Limited | Information & communication | 2024 |
| TPL Santi Limited | Information & communication | 2024 |
| TPL Upgraded 2 Ltd | Information & communication | 2025 |
| TPM Brothers Ltd | Wholesale & retail | 2023 |
| TPM Pubs Ltd | Hospitality | 2023 |
| Tpmt Ltd | Construction | 2025 |
| Tppf Financial Services Limited | Extraterritorial | 1998 |
| TQH Ampthill Limited | Hospitality | 2012 |
| TR Advisory (MGT) Ltd | Professional & scientific | 2026 |
| TR Advisory Limited | Professional & scientific | 2024 |
| Trace Design Limited | Wholesale & retail | 2001 |
| Trace ME HIT Squad Ltd | Information & communication | 2020 |
| Tracey Arnold Social Work Consultancy Ltd | Health & social care | 2025 |
| Track a Hybrid Ltd | Administrative & support | 2026 |
| Track Capital Investments Limited | Real estate | 2017 |
| Track Maintenance Supplies Ltd | Manufacturing | 2024 |
| Track-Max (USA) Limited | Manufacturing | 2025 |
| Track-Max Limited | Manufacturing | 2025 |
| Tracking-Shot Ltd | Information & communication | 2023 |
| Trackletic Clothing Ltd | Wholesale & retail | 2024 |
| Trackside Campers Ltd | Manufacturing | 2022 |
| Trackstax Limited | Information & communication | 2025 |
| Trackweigh Limited | Manufacturing | 2023 |
| Tractel (UK) Limited | Manufacturing | 1954 |
| Trade Carpets & Beds Limited | Wholesale & retail | 2010 |
| Trade FIX Solutions Ltd | Administrative & support | 2025 |
| Trade Furnishings Ltd | Manufacturing | 2025 |
| Trade Retail Partners Limited | Wholesale & retail | 2023 |
| Trade Surplus Limited | Manufacturing | 2009 |
| Trade Union Legal LLP | | 2013 |
| Trade Warehouse Ltd | Wholesale & retail | 2021 |
| Trade WR Limited | Wholesale & retail | 2023 |
| TRADE2TORQUE Ltd | Wholesale & retail | 2025 |
| Tradeforce Recruitment Ltd | Administrative & support | 2026 |
| Tradeley LLP | | 2024 |
| Trademaster Approved Limited | Construction | 2017 |
| Trademet Ltd | Water & waste | 2014 |
| Trader Doors Ltd | Wholesale & retail | 2019 |
| Trader Technology Training Limited | Information & communication | 2012 |
| Traderite Global Ltd | Real estate | 2021 |
| Traderlink Limited | Transport & logistics | 2025 |
| Trades and Construction Accountants Ltd | Extraterritorial | 2024 |
| Trades Build Collective Ltd | Construction | 2026 |
| Trades Business Media Ltd | Other services | 2020 |
| Tradevoice Ltd | Information & communication | 2026 |
| Trading Harbour Limited | Wholesale & retail | 2024 |
| Traditional Window Fittings Limited | Wholesale & retail | 2008 |
| Tradmill Investments Limited | Financial services | 2021 |
| Trafalgar Court Northern Limited | Real estate | 1994 |
| Trail Fit Ltd | Wholesale & retail | 2025 |
| Trailblaze Trailers Limited | Manufacturing | 2013 |
| Trailblaze-Her Limited | Wholesale & retail | 2025 |
| Train With Elle Ltd | Education | 2025 |
| TRAIN2TEACHUK Ltd | Other services | 2018 |
| Training for Leading Ltd | Education | 2024 |
| Training Plus (Merseyside) Limited | Professional & scientific | 2001 |
| Trainweigh Ltd | Manufacturing | 2023 |
| Trainx Limited | Professional & scientific | 2017 |
| Tram Stop Ltd | Hospitality | 2026 |
| Trampus Music Limited | Arts & recreation | 2002 |
| Tramsheds Property Management Limited | Real estate | 2007 |
| Tramway Services Ltd | Wholesale & retail | 2025 |
| Trandados W6 Consulting Ltd | Financial services | 2026 |
| Tranquality Solutions Limited | Health & social care | 2017 |
| Tranquil Beauty @ the Woodlands Limited | Other services | 2013 |
| Tranquility Skincare Health and Beauty Salon Limited | Other services | 2009 |
| Trans Kris CH Ltd | Transport & logistics | 2018 |
| Trans What YOU Will Theatre CIC | Arts & recreation | 2026 |
| Transact Corporate Finance Limited | Professional & scientific | 2015 |
| Transaction Network Services (UK) Limited | Information & communication | 1994 |
| Transaction Translators Ltd | Professional & scientific | 1999 |
| Transatlantic Chivic Global Limited | Wholesale & retail | 2025 |
| Transfigos Ltd | Manufacturing | 2025 |
| Transform Britain Ltd | Professional & scientific | 2023 |
| Transform Physiotherapy Limited | Health & social care | 2026 |
| Transformation in Action Limited | Professional & scientific | 2023 |
| Transforming Film Limited | Information & communication | 2023 |
| Transgear Units Limited | Manufacturing | 2002 |
| Transglobal Associates LLP | | 2017 |
| Transhaven Limited | Administrative & support | 1991 |
| Transition International Limited | Manufacturing | 2003 |
| Transition Investments Limited | Financial services | 2023 |
| Transition Metals Limited | Administrative & support | 2010 |
| Transition Participations Limited | Manufacturing | 1994 |
| Transition Sheffield Limited | Administrative & support | 2006 |
| Transition Solutions Limited | Manufacturing | 2013 |
| Translink Corporate Finance (Sumer BHP) Limited | Professional & scientific | 2025 |
| Transmarine Limited | Transport & logistics | 2025 |
| Transmission Holdings Limited | Manufacturing | 2017 |
| Transpark Auto Electrical Limited | Wholesale & retail | 2024 |
| Transport & Logistics Compliance Training Limited | Education | 2019 |
| Transport and Logistics Training Ltd | Education | 2004 |
| Transport Direct & Service Ltd | Other services | 2016 |
| Transport UK to EU Ltd | Transport & logistics | 2023 |