| Tribe Beautiful Limited | Other services | 2024 |
| Tricia Woodhead Consulting Limited | Health & social care | 2011 |
| Tricky Developments Limited | Information & communication | 2013 |
| Trilogy Media Productions Limited | Information & communication | 2002 |
| Trilogy Talent Limited | Administrative & support | 2023 |
| Trinity Safeguarding Ltd | Professional & scientific | 2015 |
| Trinity Square (Oxford) Ltd | Real estate | 2012 |
| Trinity Telecoms Limited | Information & communication | 2023 |
| Trinity Way Ltd | Professional & scientific | 2010 |
| TRIPTYCH360 Ltd | Information & communication | 2026 |
| Tritanium Space, Defence and Technology Ltd | Administrative & support | 2024 |
| Trond Ltd | Wholesale & retail | 2025 |
| Tror Limited | Professional & scientific | 2013 |
| Trotman Indigo Publishing Limited | Information & communication | 2021 |
| Troudeau Ltd | Wholesale & retail | 2020 |
| Troup Curtis Engineering Company Limited | Professional & scientific | 1920 |
| Troup Curtis Limited | Professional & scientific | 2020 |
| Trovesse Limited | Wholesale & retail | 2022 |
| True Charge Limited | Construction | 2025 |
| True Sage Ltd | Wholesale & retail | 2020 |
| True Value Property Advice Limited | Real estate | 2025 |
| Truespeed Communications Ltd | Information & communication | 2014 |
| Truespeed Ltd | Information & communication | 2016 |
| Trueview Medical Ltd | Professional & scientific | 2022 |
| Trufflehog Ltd | Professional & scientific | 2025 |
| Trustease Property Management Limited | Real estate | 1998 |
| Truten Group Ltd | Financial services | 2024 |
| TRW Properties Limited | Real estate | 2024 |
| Trypoint (Services) Limited | Financial services | 2012 |
| Trypoint LLP | | 2012 |
| TS Waller Investments Ltd | Real estate | 2020 |
| TSL Company Services Limited | Extraterritorial | 2005 |
| Tso&Makwae Ltd | Health & social care | 2016 |
| TSP Industries Limited | Professional & scientific | 1997 |
| TSP Property Management Limited | Real estate | 2020 |
| Tuana Holdings Limited | Financial services | 2020 |
| Tuckwell London Limited | Wholesale & retail | 2025 |
| Tuco Holdings Limited | Financial services | 2003 |
| Tuesday UK Newco Ltd | Information & communication | 2025 |
| Tumi (Crafts) Limited | Administrative & support | 2000 |
| Tumi (Music) Limited | Arts & recreation | 1990 |
| Tumi Cargo Ltd | Transport & logistics | 2019 |
| Tumi Limited | Wholesale & retail | 1988 |
| Tumi Music (Editorial) Limited | Information & communication | 1997 |
| Tumi Productions Limited | Information & communication | 2002 |
| Turf Football Art Ltd | Arts & recreation | 2020 |
| Turn UP Ltd | Arts & recreation | 2020 |
| Turner and Partners LLP | | 2018 |
| Turner Consultancy Ltd | Professional & scientific | 2014 |
| Turner Tubs Property Limited | Real estate | 2022 |
| Tvcj Ltd | Information & communication | 2017 |
| Tvme Ltd | Information & communication | 2025 |
| TW Jones & Sons Building Projects Limited | Construction | 2019 |
| Tweed Industries Ltd | Information & communication | 2016 |
| Twenty Eight Beer Limited | Information & communication | 2025 |
| Twenty Two Works Ltd | Construction | 2022 |
| Twenty-Eight Great Pulteney Street (Bath) Management Limited | Households | 1978 |
| Twenty-One MP Ltd | Wholesale & retail | 2021 |
| Twenty-Three Great Stanhope Street (Bath) Management Limited | Households | 1979 |
| Twenty-Two Great Stanhope Street (Bath) Management Limited | Households | 1978 |
| Twerton Bakers Ltd | Hospitality | 2023 |
| Twerton Village Hall | Administrative & support | 1998 |
| TWF (Bath) Ltd | Construction | 2011 |
| Twin City Developments Ltd | Construction | 2010 |
| Twinwall ICF Ltd | Professional & scientific | 2026 |
| TWJ ALE & Food Company Limited | Hospitality | 2015 |
| Two Sisters (Bath) Limited | Real estate | 2015 |
| Two Track Limited | Real estate | 2021 |
| Tyning Farms (1987) Limited | Agriculture & fishing | 1987 |
| Tyning Homes Ltd | Real estate | 2024 |
| Tyning Meadows Management Limited | Households | 2018 |
| Tynings Fish and Chips Ltd | Hospitality | 2019 |
| Tynings Limited | Real estate | 2012 |
| Typecot Limited | Wholesale & retail | 1978 |
| Tyratech Limited | Extraterritorial | 2014 |
| U'Lippu Imports Ltd | Wholesale & retail | 2026 |
| U.K. Food Machinery Ltd | Wholesale & retail | 2018 |
| U2COM Limited | Information & communication | 2001 |
| Uber Clothing Ltd | Wholesale & retail | 2006 |
| UBI Maior Limited | Financial services | 2016 |
| Ubicolor Ltd | Information & communication | 2014 |
| UEH Property Management Company Limited | Real estate | 2018 |
| Ugcagency Ltd | Information & communication | 2017 |
| UK CUP of Tea Company Ltd | Wholesale & retail | 2023 |
| UK Drawing Booth Ltd | Arts & recreation | 2016 |
| UK Healthcare Solutions Limited | Health & social care | 2005 |
| UK Independent Colleges Limited | Education | 2017 |
| UK MEC Ltd | Other services | 2020 |
| UK Optical Limited | Administrative & support | 2015 |
| UK Pump Supplies Limited | Wholesale & retail | 2007 |
| UK Renewable Innovations & Developments Ltd | Professional & scientific | 2023 |
| UK Smart Hub Ltd | Hospitality | 2015 |
| UK Spa Ltd | Other services | 2023 |
| UK Sports Innovations Group Limited | Arts & recreation | 2008 |
| Ultimetrics Ltd | Extraterritorial | 2023 |
| Ultra Engineering Ltd | Manufacturing | 2020 |
| Umiumi Limited | Wholesale & retail | 2024 |
| Unbiaz Ltd. | Professional & scientific | 2015 |
| Uncle Winston's Ltd | Wholesale & retail | 2025 |
| Underived Limited | Information & communication | 2015 |