| Tieg Limited | Real estate | 2014 |
| Tiernan & Reynolds | | 1986 |
| Tiger BK Ltd | Professional & scientific | 2021 |
| Tiko 20-35 Ltd | Wholesale & retail | 2025 |
| Tilbury Hand Car Wash Limited | Wholesale & retail | 2025 |
| Tilda Limited | Manufacturing | 1970 |
| TIM & MAY UK Ltd | Real estate | 2020 |
| TIM Foot Limited | Education | 2003 |
| TIM Rennie Associates Limited | Professional & scientific | 1995 |
| TIM Sport Ltd | Professional & scientific | 2003 |
| Timage & Co. Limited | Wholesale & retail | 1976 |
| Timber Health Limited | Health & social care | 2024 |
| Timber Metallics Ltd | Manufacturing | 2004 |
| Timbergrain Limited | Real estate | 2000 |
| Time Saver Drinks Ltd | Wholesale & retail | 2015 |
| Time to Time Shopfronts and Shutters Limited | Construction | 2024 |
| TIME2WAKE Ltd | Wholesale & retail | 2001 |
| Times Energy Limited | Wholesale & retail | 2007 |
| Timna Limited | Hospitality | 2002 |
| Timothy Woods Project Services Limited | Construction | 2001 |
| Timperley West Ltd | Real estate | 2023 |
| Tine Court (Hainault) Management Company Limited | Real estate | 2003 |
| Tineetrade Limited | Information & communication | 1997 |
| Tiptree Management Co Limited | Households | 2004 |
| Titan Apps Ltd | Information & communication | 2025 |
| Titan Externals Ltd | Construction | 2024 |
| Titan Industrial GAS UK Ltd | Wholesale & retail | 2025 |
| Titanic Leathers Limited | | 1973 |
| TIV Supply Limited | Wholesale & retail | 2026 |
| TJ Properties (Essex) Ltd | Real estate | 2019 |
| TK Style Outlet Ltd | Wholesale & retail | 2026 |
| TLM Property Group Limited | Real estate | 2022 |
| TMF Investment Limited | Health & social care | 2013 |
| TN PVT Limited | Wholesale & retail | 2026 |
| TNH Properties Limited | Real estate | 1998 |
| TNS Business Ltd | Wholesale & retail | 2025 |
| TO Imagine IT Solutions Ltd | Wholesale & retail | 2025 |
| To-By (ALL Roads) Transport Limited | | 1955 |
| Tobiat Consulting Limited | Information & communication | 2002 |
| Tobipa Ltd | Wholesale & retail | 2018 |
| Tobs Consulting Limited | Professional & scientific | 2002 |
| Todcharm Limited | Real estate | 1980 |
| Together Partnership LLP | | 2020 |
| Togo Homes Limited | Construction | 1995 |
| Tokia Limited | Information & communication | 2022 |
| Toks & Wendy Consulting Limited | Health & social care | 2005 |
| Tola Plant Hire Limited | Construction | 1998 |
| Tolatope & Associates Limited | Professional & scientific | 1999 |
| Tollesbury Marina Limited | Arts & recreation | 1970 |
| Tollesbury Saltings Limited | Arts & recreation | 1980 |
| Tomps Limited | Wholesale & retail | 2007 |
| Tomsop Consult Limited | Construction | 2014 |
| TON Launchpad Ltd | Professional & scientific | 2024 |
| Tonicville Limited | | 1983 |
| Tony Mann Limited | Professional & scientific | 2004 |
| Tonzo Limited | Information & communication | 2021 |
| Toothcare Limited | Health & social care | 2006 |
| Top Care Homes Limited | Health & social care | 2004 |
| Top Command Security Services Ltd | Financial services | 2025 |
| Top G Company Ltd | Wholesale & retail | 2025 |
| Top One Construction Limited | Wholesale & retail | 1998 |
| Top Tier Boxing Ltd | Arts & recreation | 2022 |
| Topaize Limited | Information & communication | 2020 |
| Topaz Care and Support Company Limited | Health & social care | 2016 |
| Topsec Solutions Limited | Administrative & support | 2023 |
| Topstar Ventilation Limited | Administrative & support | 2025 |
| Toptype Limited | Manufacturing | 1981 |
| Topulent Business Solutions Limited | Real estate | 2016 |
| Total Accounting Solutions Limited | Professional & scientific | 2005 |
| Total Close Protection Limited | Administrative & support | 2003 |
| Total Global Prosperity Ltd | Wholesale & retail | 2025 |
| Total Information Solutions Limited | Other services | 2000 |
| Total Secured Ltd | Professional & scientific | 2024 |
| Total Testing Ltd | Information & communication | 2005 |
| Total Transport London Ltd | Transport & logistics | 2017 |
| Touch London Ltd | Hospitality | 2025 |
| Touchpedia Ltd | Information & communication | 2023 |
| Touqeer Iqbal Limited | Information & communication | 2025 |
| Tower International Limited | Wholesale & retail | 2004 |
| Towfeeq Ahmad Trading Ltd | Wholesale & retail | 2025 |
| Towler Engineering Limited | Manufacturing | 1974 |
| Towmate Holdings Ltd | Financial services | 2025 |
| Town and Countryside Gardens Limited | Administrative & support | 2005 |
| Tozai Trading Limited | Administrative & support | 1999 |
| TPW Services Limited | Manufacturing | 1996 |
| TPX Services Limited | Administrative & support | 2007 |
| Traanscom Ltd | Wholesale & retail | 2025 |
| Trackadobestock Ltd | Information & communication | 2025 |
| Trackworld Limited | Wholesale & retail | 2005 |
| Tractward Limited | Real estate | 1981 |
| Trade Garden Services Ltd | Wholesale & retail | 2023 |
| Trade Price Wallcoatings Ltd | Construction | 2003 |
| TRADER365 Ltd | Education | 2025 |
| Trading Faces Limited | Administrative & support | 1992 |
| Traditional Floor Screeds Limited | Construction | 2005 |
| Tradpin Construction Limited | Construction | 1973 |
| Trailer Park Capital Partners Limited | Transport & logistics | 2022 |
| Train and Improve Football Ltd | Other services | 2023 |
| Training World Limited | Administrative & support | 1993 |
| Traitors Gate Limited | Other services | 1999 |