| Total Attractions Limited | Arts & recreation | 2019 |
| Total Bounceout Ltd | Arts & recreation | 2019 |
| Touchwood Carpentry & Construction Ltd | Construction | 2018 |
| Town Farm Bletchingley Management Limited | Households | 1984 |
| Townsend Information Systems Limited | Information & communication | 1998 |
| Toyotec Limited | Wholesale & retail | 2010 |
| Tpbdevelopment Ltd | Professional & scientific | 1988 |
| TR Projects Limited | Construction | 2018 |
| Trade AAA Limited | Wholesale & retail | 2021 |
| Trade Winds Audio Ltd | Information & communication | 2022 |
| Tradekats Ltd | Wholesale & retail | 2023 |
| Tradeplan Insurance Services Limited | Extraterritorial | 2002 |
| Trafalgar House Line Limited | Professional & scientific | 1947 |
| Trafalgar House Steam-Ship Company Limited | Professional & scientific | 1878 |
| Trafalgar Properties Limited | Financial services | 1924 |
| Tranoca Limited | Health & social care | 2015 |
| Transforemotion Limited | Professional & scientific | 2015 |
| Transworld Global Courier Limited | Transport & logistics | 2017 |
| Travelling Trends South East Limited | Wholesale & retail | 2009 |
| TRE Creative Design & Photo Ltd | Professional & scientific | 2025 |
| Trekstride Events Ltd | Arts & recreation | 2025 |
| Tresco Estates Limited | Other services | 1986 |
| Trevor Blake Fit OUT Limited | Construction | 2016 |
| Trevor Woods Ltd | Professional & scientific | 2019 |
| Tridar Property Ltd | Real estate | 2020 |
| Trigg Space Ltd | Professional & scientific | 2023 |
| Trinity Driving School Limited | Education | 2012 |
| Trinity Medicolegal LLP | | 2022 |
| Trion Private Limited | Financial services | 2020 |
| Trip Logistic Ltd | Transport & logistics | 2024 |
| Tripology Media Ltd | Wholesale & retail | 2024 |
| Tripsitta Ltd | Professional & scientific | 2018 |
| Tristan Court Management Company Limited | Hospitality | 1986 |
| Tropictarn Limited | Real estate | 1982 |
| Trout Mask Ltd | Information & communication | 2016 |
| Truevale Luxe Ltd | Wholesale & retail | 2025 |
| Trume Ltd | Information & communication | 2023 |
| Truth London Ltd | Wholesale & retail | 2017 |
| Tsavo Enterprises Limited | Manufacturing | 2011 |
| Tudor Beech Management Company Ltd | Households | 2018 |
| Tudor Carriage Company Limited | Transport & logistics | 2003 |
| Tulip Firm Limited | Health & social care | 2019 |
| Tupwood Lane (Caterham) Management Limited | Households | 2006 |
| Turnstone Limited | Information & communication | 1994 |
| TV Production Services Limited | Information & communication | 2003 |
| Twineham (Almondsbury) Limited | Real estate | 2019 |
| Twineham Property Holdings Limited | Professional & scientific | 2004 |
| Twinteks Ltd | Construction | 2022 |
| Twisted Pear Design Limited | Wholesale & retail | 2017 |
| Two Snipe Consulting Ltd | Professional & scientific | 2025 |
| Twojohns Consulting Limited | Information & communication | 2015 |
| TX3 Ltd | Transport & logistics | 2025 |
| Tylehurst Instruments Ltd | Information & communication | 2011 |
| Tyre Patrol Ltd | Manufacturing | 2026 |
| U B R Management Company Limited | Households | 1998 |
| U.T.A. Freight (U.K.) Limited | Financial services | 1981 |
| UE Universal Element Limited | Water & waste | 2023 |
| UGP100 Limited | Wholesale & retail | 2019 |
| Uhuru Proptech Limited | Information & communication | 2020 |
| UK Cloudkeeper Ltd | Information & communication | 2026 |
| UK Education IV Consulting Limited | Education | 2025 |
| UK Electrical Safety Limited | Construction | 2010 |
| UK Office Direct Limited | Wholesale & retail | 2002 |
| UK Property Assistance Ltd | Administrative & support | 2010 |
| UK Reliable Cars Ltd | Transport & logistics | 2025 |
| UK Site Direct Ltd | Administrative & support | 2024 |
| Ukciv Ltd | Wholesale & retail | 2024 |
| Ukcvr Ltd | Financial services | 2024 |
| Ukin Ltd | Wholesale & retail | 2018 |
| Ukjpa Ltd | Arts & recreation | 2025 |
| Ultralite Limited | Arts & recreation | 1999 |
| Ultrasun (UK) Limited | Wholesale & retail | 1997 |
| Unduit Limited | Information & communication | 2024 |
| Union Wharf Narrowboats Limited | Real estate | 1998 |
| Unite Business Ltd | Hospitality | 2019 |
| United Helicopters Limited | Transport & logistics | 1955 |
| Universal Emporium Ltd | Transport & logistics | 2020 |
| Universal Foodservice Spares & Equipment Ltd | Wholesale & retail | 2022 |
| Upland Property Services Limited | Real estate | 2013 |
| Upland Renovations Limited | Construction | 2025 |
| Urban Climate Solutions Limited | Energy | 2026 |
| Urban Nest Property Solutions Ltd | Real estate | 2024 |
| US Executive Travel Ltd | Transport & logistics | 2025 |
| US in a BUS | Other services | 2001 |
| USA Cars Limited | Extraterritorial | 2011 |
| USA COP Cars Limited | Administrative & support | 2010 |
| Utilities Consultant Ltd | Professional & scientific | 2021 |
| Uxologist Ltd | Education | 2025 |
| V & O Renovations Ltd | Construction | 2023 |
| V&Eks Social Work Limited | Professional & scientific | 2023 |
| V&L Property Services (Surrey) Ltd | Construction | 2021 |
| V&V Gold Limited | Wholesale & retail | 2025 |
| Vacantc Limited | Administrative & support | 2024 |
| Valcor Ltd | Real estate | 2022 |
| Valery Court Residents Association Limited | Households | 1993 |
| Valler Holdings Limited | Real estate | 1996 |
| Valmora Ltd | Wholesale & retail | 2017 |
| Value Exchange AI Limited | Information & communication | 2025 |
| Vancegrove Limited | Manufacturing | 2010 |
| Vanilla and Gold Ltd | Professional & scientific | 2010 |