| Team Green Health CIC | Health & social care | 2026 |
| Team Growers Limited | Wholesale & retail | 2025 |
| Team PB Racing Limited | Arts & recreation | 2010 |
| Team Pocket Ltd | Wholesale & retail | 2024 |
| Team Teddy Ltd | Professional & scientific | 2024 |
| Tebays Garden Maintenance Ltd | Administrative & support | 2020 |
| Tech Asset Management Limited | Extraterritorial | 2010 |
| Tech Compliance Limited | Construction | 1999 |
| Tech Engineering Group Ltd | Financial services | 2010 |
| Tech Medical Services Limited | Health & social care | 2017 |
| Tech Spark Retail Ltd | Wholesale & retail | 2018 |
| Tech-Tel Holdings Ltd | Real estate | 2021 |
| Tech-Tel Services Direct Ltd | Information & communication | 2010 |
| Techfil Europe Ltd | Wholesale & retail | 2006 |
| Techify Hub Ltd | Other services | 2024 |
| Techmedia Group Ltd | Information & communication | 2019 |
| Technic-Colour Smart Repairs Limited | Wholesale & retail | 2025 |
| Technica Pharmaceuticals Limited | Wholesale & retail | 2023 |
| Technical Asset Management Limited | Construction | 2004 |
| Technical Fixings Solutions Holdings Limited | Other services | 2020 |
| Technical Fixings Solutions Limited | Wholesale & retail | 2008 |
| Technical Pharma Services Ltd | Professional & scientific | 2019 |
| Technickon Ltd | Construction | 2006 |
| Technofilm Limited | Construction | 1996 |
| Technoframe BUS & Rail Ltd | Manufacturing | 2020 |
| Techwise Talent Limited | Administrative & support | 2024 |
| Tecknet Limited | Information & communication | 2014 |
| Tecomak Environmental Services Limited | Other services | 1995 |
| Tecomak Limited | Other services | 1974 |
| TED Apprenticeships Limited | Administrative & support | 2020 |
| TED Consult Limited | Professional & scientific | 2020 |
| TED Digital Limited | Professional & scientific | 2020 |
| TED Education Limited | Education | 2020 |
| Tedfast Ltd | Transport & logistics | 2024 |
| Teemax Global Limited | Transport & logistics | 2025 |
| Teetopin Limited | Wholesale & retail | 2014 |
| TEI Properties Limited | Households | 2025 |
| TEK & Sons Limited | Health & social care | 2020 |
| Tekcaj Holdings Limited | Construction | 2017 |
| Tekcast Limited | Information & communication | 2019 |
| Tekkno Systems Ltd | Information & communication | 2010 |
| Tekko Fabrication Limited | Manufacturing | 2025 |
| Teleport Studios Limited | Information & communication | 2020 |
| Tellurium Limited | Real estate | 2022 |
| Telophase Associates Ltd | Professional & scientific | 2024 |
| Telsons Builders Limited | Construction | 2002 |
| Telub Ltd | Real estate | 2022 |
| Temhouse Maintenance Limited | Households | 1972 |
| Temidewa Consulting Limited | Administrative & support | 2016 |
| Temple Cleaning Company Ltd | Administrative & support | 2020 |
| TEN Architecture and Design Ltd | Professional & scientific | 2009 |
| TEN-78 Ltd | Professional & scientific | 2019 |
| Tenacious Care Ltd | Health & social care | 2014 |
| Tender Grill Limited | Hospitality | 2020 |
| Tenerife Consultation and Services Ltd | Hospitality | 2023 |
| Tennis Together Bexley Ltd | Education | 2024 |
| Tennyson Rose Property Services Limited | Real estate | 2016 |
| Tennyson Rose Town & Country Ltd | Hospitality | 2019 |
| Tennyson Town & Country LLP | | 2019 |
| Tensor Media Group Ltd | Administrative & support | 2017 |
| Tentenplumbing Ltd | Construction | 2025 |
| Teos Advisory Limited | Professional & scientific | 2021 |
| Terence Jayes Nicholson Ltd | Transport & logistics | 2018 |
| Termimate Ltd | Information & communication | 2021 |
| Terra Calabria Ltd | Wholesale & retail | 2026 |
| Terra E Mare Limited | Hospitality | 2015 |
| Terraflux Holdings Ltd | Construction | 2025 |
| Terrific Television (BOD) Ltd | Information & communication | 2024 |
| Terrific Television (HOW) Ltd | Information & communication | 2019 |
| Terrific Television (Makery) Ltd | Information & communication | 2021 |
| Terrific Television (Monster) Ltd | Information & communication | 2023 |
| Terrific Television (MWK) Ltd | Information & communication | 2019 |
| Terrific Television (Popcast) Ltd | Information & communication | 2019 |
| Terrific Television (Rights) Ltd | Information & communication | 2018 |
| Terrific Television Ltd | Information & communication | 2016 |
| Terrific TV (UK) Ltd | Information & communication | 2021 |
| Terry Isaacs Therapy Ltd | Health & social care | 2016 |
| Terry Legacy Estates Ltd | Real estate | 2025 |
| Terry Osborne Insurance Services Limited | Financial services | 2008 |
| Terry Pawson Architects Limited | Professional & scientific | 2005 |
| Terry Poxon (Property Services) Limited | Construction | 1981 |
| Terryforch Ltd | Health & social care | 2015 |
| Tessellate Tiling Ltd | Construction | 2018 |
| Tesseract Electrical Limited | Construction | 2022 |
| Test Instrument Centre Limited | Wholesale & retail | 2013 |
| Teston Village Stores CIC | Wholesale & retail | 2013 |
| Teven Properties Limited | Real estate | 2022 |
| Texim Logistics Ltd | Transport & logistics | 2025 |
| Tfcgb Ltd | Extraterritorial | 2003 |
| TG Delivery Group Ltd | Wholesale & retail | 2023 |
| TG Serv Limited | Construction | 2014 |
| Tgfa Consulting Limited | Professional & scientific | 2013 |
| Thai Cleaning and Property Ltd | Other services | 2014 |
| Thai Rice Maidstone Limited | Hospitality | 2021 |
| Thames Connect Ltd | Financial services | 2025 |
| Thames Group Hospitality Limited | Hospitality | 2024 |
| Thames Hudson Limited | Professional & scientific | 2025 |
| Thames Investments (Holdings) Limited | Professional & scientific | 1970 |
| Thames Investments Limited | Professional & scientific | 1949 |
| Thames View Property Ltd | Real estate | 2020 |