| TOM Blizzard Golf Ltd | Arts & recreation | 2024 |
| TOM Cannon Limited | Arts & recreation | 2015 |
| TOM Holland Limited | Arts & recreation | 2010 |
| TOM Rawlings Racing Ltd | Arts & recreation | 2019 |
| TOM Solomon Access Training Ltd | Education | 2026 |
| Tonfuller Consultancy Limited | Information & communication | 2015 |
| Tonks & Firkin Residential Lettings Limited | Administrative & support | 2008 |
| Tony Smith and Sons Limited | Construction | 2007 |
| TOOLS4TECHNOLOGY Ltd | Extraterritorial | 2009 |
| Toona Limited | Arts & recreation | 2016 |
| Toorak Limited | Administrative & support | 2007 |
| Topglass Ltd | Manufacturing | 2018 |
| Total Carpentry Ltd | Construction | 2020 |
| Total Metal Recovery Limited | Water & waste | 2005 |
| Total Trace Heating Ltd | Construction | 2026 |
| Total Voip Solutions Ltd | Information & communication | 2012 |
| Touch of Beauty (Bromsgrove) Limited | Other services | 2015 |
| Touchpoint Consultancy Limited | Other services | 2013 |
| Tough Medix Ltd | Health & social care | 2024 |
| Town & Country &Co Window Cleaning Ltd | Administrative & support | 2024 |
| TP Building and Interiors Limited | Construction | 2017 |
| TP Iconic Management Ltd | Households | 2024 |
| TPN Capital Ltd | Real estate | 2019 |
| TR Fitness (Holdings) Limited | Arts & recreation | 2021 |
| TR Fitness Studios Limited | Arts & recreation | 2025 |
| Tracy Anderson Mind & Body UK Limited | Arts & recreation | 2010 |
| TRADE10 Ltd | Information & communication | 2015 |
| Tradetec Services Ltd | Construction | 2024 |
| Tradie - Where Tradesmen Thrive Ltd | Information & communication | 2023 |
| Tradvia Ltd | Wholesale & retail | 2025 |
| Traffic Safety & Management Limited | Construction | 2000 |
| Trailer Hire (Worcestershire) Ltd | Administrative & support | 2026 |
| Trainer Armour Limited | Manufacturing | 2021 |
| Transform Carpets & Flooring Limited | Construction | 2017 |
| Transform Flooring Limited | Construction | 2014 |
| Transport & Storage Solutions Ltd | Transport & logistics | 2025 |
| Transtip Limited | Mining & quarrying | 2021 |
| Trebuchet Games Ltd | Wholesale & retail | 2014 |
| Trelleborg Building Systems UK Limited | Extraterritorial | 1979 |
| Trevor James Recruitment Ltd | Administrative & support | 2025 |
| Trew Online Holdings Ltd | Information & communication | 2021 |
| Trew Self Ltd | Information & communication | 2021 |
| TRI Click Ltd | Wholesale & retail | 2022 |
| TRI Investments Ltd | Administrative & support | 2017 |
| Triangle Capital | Financial services | 2019 |
| Triassic Business Centre Limited | Administrative & support | 2018 |
| Trickster Productions Ltd | Information & communication | 1999 |
| Trigger Financial Services Limited | Financial services | 2017 |
| Trimatt Ltd | Manufacturing | 2021 |
| Trinity FLO Limited | Construction | 2019 |
| Trinity Grove Studios Limited | Professional & scientific | 2024 |
| Triple H Racking Services Ltd | Construction | 2020 |
| Triple RRR Ltd | Financial services | 2017 |
| TRISHUL33 Ltd | Hospitality | 2025 |
| Trobbiani & Scott LLP | | 2022 |
| Troth and Sons Electrical Services Ltd | Construction | 2023 |
| Troy Kidsley Architecture Limited | Professional & scientific | 2014 |
| TRS Roofing Services Limited | Construction | 2007 |
| Trucolour UK Ltd | Wholesale & retail | 2020 |
| Trulee Pet Supplies Limited | Wholesale & retail | 2024 |
| Truthvine C.I.C. | Information & communication | 2015 |
| TRY Scoring Runs Ltd | Arts & recreation | 2014 |
| TSB Consultants Ltd | Professional & scientific | 2019 |
| TSB UK Properties Ltd | Real estate | 2020 |
| TSJ Project Consultancy Limited | Information & communication | 2016 |
| Tskm Holdings Ltd | Real estate | 2021 |
| TT Capital Holdings Ltd | Financial services | 2025 |
| TT Capital Ltd | Real estate | 2024 |
| TT Capital Opco Ltd | Real estate | 2025 |
| Ttl-Europe Ltd | Professional & scientific | 2024 |
| Tudor Hall Private Day Nursery Limited | Education | 2019 |
| Tungsten Telecoms Limited | Information & communication | 2011 |
| Tupney Productions Ltd | Information & communication | 2015 |
| Turkdelboy Ltd | Hospitality | 2025 |
| Turners OFF Road Limited | Wholesale & retail | 2021 |
| Tutnall Grange Management Company Limited | Households | 2002 |
| Tutoraction Limited | Administrative & support | 1986 |
| Tutu & Giovanna Holdings Ltd | Financial services | 2025 |
| Tweedy Rose Limited | Professional & scientific | 2024 |
| Twelve CFE Limited | Hospitality | 2022 |
| Twickenham Parking Developments Ltd | Construction | 2018 |
| Twlog Ltd | Manufacturing | 2026 |
| Two Dogs Barking Limited | Information & communication | 2024 |
| Two-Footed Productions Limited | Arts & recreation | 2017 |
| TWO9NINE - Engineering Ltd | Construction | 2024 |
| Tynan's Decorating Co Ltd | Construction | 2024 |
| Type 1 Technics Limited | Manufacturing | 2019 |
| Tyrannosaurus Investment Company Limited | Real estate | 2003 |
| Tyrecare (Midlands) Limited | Wholesale & retail | 2001 |
| U.D.C. (Midlands) Limited | Construction | 1996 |
| Udenom Limited | Information & communication | 2022 |
| UDN Brothers Ltd | Hospitality | 2019 |
| UK Birse Company Limited | Information & communication | 2025 |
| UK Cladding Supplies Ltd | Other services | 2024 |
| UK Electrical Holdings Limited | Professional & scientific | 2000 |
| UK Electrical Installations Limited | Construction | 1995 |
| UK Electrical Properties LLP | | 2011 |
| UK Fibre Ltd | Information & communication | 2019 |
| UK Helping Hands Clothing Co Limited | Wholesale & retail | 2013 |
| UK High Access Ltd | Construction | 2022 |