| Thmg Holding Ltd | Wholesale & retail | 2023 |
| Thomas Air Services (TAS) Ltd | Construction | 2020 |
| Thomdern Limited | Extraterritorial | 2017 |
| Thorncroft Property Limited | Real estate | 2023 |
| Thornegate Process Consulting Ltd | Professional & scientific | 2024 |
| Thornford Consulting Ltd | Financial services | 2019 |
| Thornton Tomasetti Romsey Limited | Professional & scientific | 1975 |
| Three Wise Whippets Ltd | Households | 2025 |
| Thrive Architects (South West) Limited | Professional & scientific | 2012 |
| Thrive Architects (Thames Valley) Limited | Professional & scientific | 2020 |
| Thrive Architects Limited | Professional & scientific | 1988 |
| Thrive Design Limited | Professional & scientific | 2014 |
| Thrive Landscaping Limited | Professional & scientific | 2014 |
| Thrive Planning Limited | Professional & scientific | 2014 |
| Thrive Sustainability Limited | Professional & scientific | 2014 |
| Thrive Urban Design Limited | Professional & scientific | 2014 |
| Thrumor Holdings Ltd | Financial services | 2025 |
| THS Catering Ltd | Hospitality | 2024 |
| Tickety BOO (South) Limited | Professional & scientific | 2001 |
| Tickety BOO Investments Limited | Extraterritorial | 2006 |
| Tiger Management Hampshire Ltd | Professional & scientific | 2022 |
| Tiger Motor Sport Limited | Professional & scientific | 2015 |
| Tilbury and Wilding Building Company Limited | Construction | 2019 |
| TIM Corfield Limited | Professional & scientific | 2024 |
| Timney Fowler Limited | Wholesale & retail | 2001 |
| Timsbury Manor Estates Ltd | Agriculture & fishing | 2010 |
| Timsbury Properties Limited | Real estate | 2023 |
| Tinklertastic Limited | Manufacturing | 2006 |
| TIP Top Flooring Limited | Construction | 2005 |
| Tippers UK Limited | Manufacturing | 2023 |
| Titan Composites Ltd | Manufacturing | 2025 |
| Titan Gym Ltd | Arts & recreation | 2018 |
| TM44 Services Limited | Real estate | 2023 |
| TO DO IS to BE Limited | Professional & scientific | 2011 |
| Toby Gullick Independent Family Estate Agents Limited | Real estate | 2023 |
| TOM Penny & Sons Limited | Construction | 2016 |
| Tomkat Couriers Ltd | Transport & logistics | 2022 |
| Tony's Auto Spares Limited | Wholesale & retail | 2008 |
| Tool Focus Ltd. | Wholesale & retail | 2014 |
| Tools and Accessories Group Ltd | Financial services | 2023 |
| Toothill Design Ltd | Professional & scientific | 2022 |
| Top Wash 2020 Limited | Wholesale & retail | 2009 |
| Total Body Conditioning Ltd | Arts & recreation | 2014 |
| Total Fire & Electrical Solutions Ltd | Administrative & support | 2020 |
| Total Spine Health Limited | Health & social care | 2020 |
| Totemshipway Limited | Extraterritorial | 2025 |
| Touch Building Services Group Limited | Construction | 2024 |
| Touch Building Services Limited | Construction | 2010 |
| Touch of Green Ltd | Arts & recreation | 2025 |
| Towergate RTM Company Limited | Households | 2007 |
| Town Golf Ltd | Arts & recreation | 2025 |
| TP Events Ltd | Arts & recreation | 2022 |
| Tp-Cbd Limited | Administrative & support | 2017 |
| TPS Estates (Management) Limited | Real estate | 1995 |
| Traction Partners Ltd | Transport & logistics | 2021 |
| Tradewinds Accounting Limited | Professional & scientific | 2024 |
| Tradewinds Accounting Services Limited | Professional & scientific | 2024 |
| Tram Medical Services Limited | Health & social care | 2019 |
| Transport Training Partners Ltd | Education | 2018 |
| Travelkore Limited | Health & social care | 2022 |
| TRC Group Global Limited | Financial services | 2021 |
| Treegee Limited | Health & social care | 2018 |
| Treverica Holdings Limited | Financial services | 2026 |
| Trevett & Smith Horseboxes Limited | Manufacturing | 2012 |
| TRG Property Ltd | Construction | 2023 |
| TRG Sales Solutions Limited | Professional & scientific | 2019 |
| Trickers Construction Ltd | Construction | 2024 |
| Trickers Landscaping and Tree Surgery Ltd | Construction | 2023 |
| Trickers Limited | Administrative & support | 2019 |
| Trojan DOT Limited | Administrative & support | 2022 |
| Trojan Financial Services Limited | Financial services | 2017 |
| Trouvaille Trading Dorset Limited | Administrative & support | 2007 |
| True North Maritime Limited | Transport & logistics | 2025 |
| True Origin Technology Ltd. | Information & communication | 2017 |
| Trumpelmann Medical Limited | Health & social care | 2013 |
| Trumpelmann Medical Services LLP | | 2026 |
| Trusted HR Solutions Limited | Professional & scientific | 2017 |
| Tsml Developments Limited | Professional & scientific | 2013 |
| Tsml Holdings Limited | Financial services | 2013 |
| TSS Engineering Services Ltd | Manufacturing | 2017 |
| TTC Management Limited | Real estate | 2023 |
| Tuinhuis Ltd | Professional & scientific | 2024 |
| Tunney Limited | Health & social care | 2021 |
| Turner & Pooch Dog Grooming Ltd | Other services | 2021 |
| Turner Financial Translators Limited | Administrative & support | 2016 |
| Turner Hardy & Co Limited | Wholesale & retail | 2016 |
| Turner Historic Automobiles Ltd | Wholesale & retail | 2018 |
| Tutte and Thomas Limited | Wholesale & retail | 1947 |
| TW Plumbing and Heating Limited | Construction | 2019 |
| Two Birds Style Ltd | Wholesale & retail | 2026 |
| TX Squared Ltd | Information & communication | 2003 |
| Tynemouth House RTM Company Ltd | Households | 2026 |
| Tyrone Carpenter Ltd | Health & social care | 2018 |
| U&P Recruitment Limited | Administrative & support | 2022 |
| UA Group Holdings Ltd | Financial services | 2023 |
| UA1 Ltd | Administrative & support | 2023 |
| UA5 Ltd | Professional & scientific | 2023 |
| UCL Projects Ltd | Other services | 2025 |
| UCS (Southern) Ltd | Transport & logistics | 2025 |
| UHM and LEE Medical Ltd | Health & social care | 2025 |