| T.I Removals Ltd | Transport & logistics | 2021 |
| T2 Square Holdings Limited | Real estate | 2024 |
| T4 Teachers.Com Ltd | Education | 2025 |
| T4KU Ltd | Health & social care | 2015 |
| T9 Labs Ltd | Information & communication | 2026 |
| TA Bristol Ltd | Hospitality | 2025 |
| TA Gear Ltd | Wholesale & retail | 2012 |
| TA Newquay Limited | Administrative & support | 2026 |
| Tabak Limited | Hospitality | 2015 |
| Taberman Consulting Limited | Administrative & support | 2014 |
| Tabula Construction Ltd | Construction | 2023 |
| Taco Bout Flavours Limited | Hospitality | 2025 |
| Tactix Academy Ltd | Other services | 2024 |
| TAG Catering Equipment UK Limited | Manufacturing | 1997 |
| TAG Sleaford Limited | Real estate | 2020 |
| Tagmaster UK Limited | Administrative & support | 1999 |
| Tahmeltan Limited | Other services | 2021 |
| Tailor Insurance Services Limited | Financial services | 2017 |
| Tailoredtothet Ltd | Wholesale & retail | 2023 |
| Taks 247 Care Ltd | Health & social care | 2024 |
| Taks Healthcare Ltd | Transport & logistics | 2015 |
| Taks Living Ltd | Real estate | 2020 |
| TAKS24-7 Limited | Administrative & support | 2021 |
| TAKS247CAREUK Ltd | Health & social care | 2026 |
| Talbot Beattie Investments Limited | Real estate | 2022 |
| Talent Reel Limited | Professional & scientific | 2008 |
| Talent Source Direct Limited | Administrative & support | 2024 |
| Talentblog Ltd | Information & communication | 2024 |
| Talk Asset Management Ltd | Real estate | 2023 |
| Talk N Tech Stevenage Ltd | Wholesale & retail | 2024 |
| Tallents Properties Limited | Real estate | 2003 |
| TAM Property Services Ltd | Real estate | 2016 |
| Tamvent Ltd | Construction | 2025 |
| Tana Medical Limited | Health & social care | 2025 |
| Tanday Dental Limited | Health & social care | 2017 |
| Tank Command Limited | Information & communication | 2022 |
| Tans , Teeth & Everythink Limited | Other services | 2025 |
| Tanwood Properties Limited | Real estate | 2017 |
| TAO Technologies Limited | Wholesale & retail | 1998 |
| TAR Restaurant Ltd | Hospitality | 2025 |
| Taraji Healthcare Company Limited | Health & social care | 2022 |
| Target Defence Ltd | Information & communication | 2020 |
| Target Global Ltd | Wholesale & retail | 2019 |
| Target to Treatment (TTT) Consulting Limited | Professional & scientific | 2016 |
| Tarla Limited | Hospitality | 2018 |
| Tash and Co Creative Ltd | Arts & recreation | 2013 |
| Task Ticketing Limited | Administrative & support | 2019 |
| TAT Pubs Ltd | Hospitality | 2023 |
| Tattersalls Management Company Limited | Households | 1988 |
| Tax ME Mummy Film Ltd | Information & communication | 2026 |
| Taylor Capital Investments Ltd | Real estate | 2023 |
| Taylor Consulting Associates Ltd | Education | 2015 |
| Taylormade Rigging Limited | Construction | 2019 |
| Taylors Rigging Solutions Ltd | Construction | 2024 |
| Tayo Adebiyi Ltd | Wholesale & retail | 2019 |
| TAZ and Lucy Limited | Other services | 2025 |
| Tazvida Limited | Administrative & support | 2023 |
| TB Lighting Ltd | Construction | 2025 |
| Tbac Studios Limited | Arts & recreation | 2022 |
| Tbaic Ltd | Arts & recreation | 2026 |
| TBG Swindon Limited | Hospitality | 2023 |
| Tbilisi Ltd | Transport & logistics | 2014 |
| Tbll Services (UK) Ltd | Administrative & support | 2025 |
| TBS Consultants Ltd | Information & communication | 2018 |
| TC Leather Services Limited | Professional & scientific | 2012 |
| TCT Fire Protection Ltd | Construction | 2022 |
| TD and MD Joiners Ltd | Construction | 2023 |
| TDI Solutions (UK) Limited | Information & communication | 2012 |
| TDS Financial Ltd | Financial services | 2021 |
| Tea Cosy 2022 Limited | Hospitality | 2022 |
| Teachers for Schools Limited | Education | 2018 |
| Teal Planning Limited | Professional & scientific | 2011 |
| Team 2 Films Ltd | Information & communication | 2019 |
| TEC Bulimar Ltd | Construction | 2018 |
| TEC Entertainment Limited | Professional & scientific | 2020 |
| Tech & Home Pro Limited | Wholesale & retail | 2025 |
| Tech 4 Change Ltd | Wholesale & retail | 2022 |
| Tech Thunder Ltd | Wholesale & retail | 2025 |
| Tech Tronx Stevenage Limited | Wholesale & retail | 2021 |
| Tech Zyro Ltd | Information & communication | 2025 |
| Technology Blueprint & Business Solutions Ltd | Information & communication | 2019 |
| Techpros Trade Limited | Manufacturing | 2019 |
| Techtribeworld Ltd | Professional & scientific | 2023 |
| Techxn Ltd | Information & communication | 2026 |
| Techzatium Ltd | Information & communication | 2025 |
| TEK Group Holdings Limited | Financial services | 2019 |
| Tek-Seis Limited | Professional & scientific | 2008 |
| Tekone Technologies Limited | Information & communication | 2013 |
| Telent Communications Pension Trust Limited | Financial services | 1965 |
| Telent Technology Services Limited | Manufacturing | 1961 |
| Telford Avenue 1958 Limited | Extraterritorial | 2015 |
| Telivo Limited | Extraterritorial | 2002 |
| Tembury Limited | Professional & scientific | 2019 |
| Temm Ltd | Hospitality | 2026 |
| Tempvs Limited | Administrative & support | 2005 |
| Temur Property Investments Ltd | Real estate | 2024 |
| Tenten Plumbing and Building Services Ltd | Construction | 2020 |
| Tentstyle Ltd | Administrative & support | 2014 |
| TEP Consultants Ltd | Construction | 2024 |
| Teraflops Limited | Real estate | 2021 |