| Tilematic Ltd | Construction | 2021 |
| TIM Butcher Limited | Wholesale & retail | 1999 |
| TIM Mann Consulting Limited | Professional & scientific | 2016 |
| TIM Murnane Consulting Limited | Professional & scientific | 2025 |
| Timber Installations Ltd | Construction | 2018 |
| Timbercroft Terrace Ltd | Construction | 2017 |
| Timeless Resources Limited | Education | 2005 |
| Timor Properties Limited | Real estate | 2017 |
| Tiontech Ltd | Manufacturing | 2020 |
| Tipa Drywall Ltd | Construction | 2025 |
| Tisbury Motors Limited | Wholesale & retail | 2006 |
| Titan Beverages Ltd | Wholesale & retail | 2022 |
| Titan Garden Buildings Limited | Manufacturing | 2006 |
| TJC Properties (Highpoint) Limited | Real estate | 2023 |
| TL Gardening & Landscaping Services Limited | Administrative & support | 2018 |
| Tlcs Communication Ltd | Information & communication | 2022 |
| TM Support Haven Ltd | Public administration | 2025 |
| Tmag OIL & GAS U.K., Ltd. | Mining & quarrying | 2014 |
| TMC Trading Limited | Wholesale & retail | 2012 |
| TMD Business Solutions Limited | Professional & scientific | 2026 |
| TMG Design and Build Limited | Construction | 2004 |
| Tmrj Properties Limited | Real estate | 2023 |
| TMT48 Limited | Financial services | 2025 |
| TMW Properties Limited | Real estate | 2014 |
| TMW Student Accommodation Limited | Real estate | 2019 |
| TO & DO Repair Ltd | Wholesale & retail | 2019 |
| Toby Cottage Limited | Hospitality | 2005 |
| Toby Pink Fitness Ltd | Health & social care | 2025 |
| Toddler Travel Diaries Ltd | Information & communication | 2025 |
| Together Vision Technology Ltd | Information & communication | 1999 |
| TOJ Homes Limited | Construction | 2008 |
| Tollhouse Boat Sales Limited | Professional & scientific | 2023 |
| TOM Cmid Ltd | Construction | 2018 |
| TOM Gordon Holdings Ltd | Professional & scientific | 2025 |
| TOM Ward Limited | Professional & scientific | 2012 |
| Tomasz Palka Ltd | Professional & scientific | 2013 |
| Tommy Atkins Media Limited | Wholesale & retail | 2008 |
| Toni LEE Limited | Other services | 2010 |
| Tonic Analytics Employee Ownership Trustees Limited | Professional & scientific | 2019 |
| Tonic Analytics Limited | Information & communication | 2015 |
| Tonic Healthcare Limited | Health & social care | 2007 |
| Tonna-Barthet Consultancy Limited | Professional & scientific | 2025 |
| Tonto Motors Group Limited | Administrative & support | 2025 |
| Tony Van Removals Limited | Transport & logistics | 2021 |
| Tony's Car Wash Ltd | Other services | 2009 |
| Toobs Art Limited | Professional & scientific | 2010 |
| Toogoods Affinity LLP | | 2011 |
| Toomuchsauce UK Ltd | Hospitality | 2021 |
| Top Click Limited | Professional & scientific | 2015 |
| Top Click Media Limited | Professional & scientific | 2005 |
| Top Property UK Limited | Real estate | 2003 |
| Top Work Designer Ltd | Construction | 2025 |
| Topaztears Limited | Financial services | 2004 |
| Topic Limited | Other services | 2025 |
| Tops Woking Best Pizza Ltd | Hospitality | 2025 |
| Topshelf Feast Limited | Hospitality | 2025 |
| Tora Consulting Limited | Professional & scientific | 2016 |
| Torin Group Ltd | Water & waste | 2025 |
| Torquil Aviation Limited | Transport & logistics | 2007 |
| Torre Cerrano Marketing Company Limited | Manufacturing | 2015 |
| Torrington Marketing Limited | Professional & scientific | 2023 |
| Torsion Design Ltd | Professional & scientific | 2024 |
| Tory Moto Co Ltd | Wholesale & retail | 2026 |
| Toryland Limited | Administrative & support | 1963 |
| Total Acoustics Ltd | Professional & scientific | 2023 |
| Total Building Solutions- for Less Ltd | Construction | 2014 |
| Total Coat Solutions Ltd | Construction | 2025 |
| Total Concrete Ltd | Construction | 2003 |
| Total Fire (UK) Limited | Administrative & support | 2009 |
| Total Tree and Stump Removal Ltd | Administrative & support | 2026 |
| Tottenham Pound Plus Ltd | Wholesale & retail | 2015 |
| Touchability Limited | Wholesale & retail | 2012 |
| Touchstone Developments (Surrey) Ltd | Construction | 2024 |
| Tower Bridge Piazza Limited | Real estate | 1990 |
| Town Grass Limited | Extraterritorial | 1990 |
| TPW Plumbing and Heating Limited | Construction | 2016 |
| Tractor Boys | Professional & scientific | 2025 |
| Trade Blueprint Ltd | Administrative & support | 2026 |
| Trade Through AID Limited | Administrative & support | 1985 |
| Trademark Effects Limited | Professional & scientific | 2021 |
| Tradicus Limited | Information & communication | 2018 |
| Trading Direct Limited | Wholesale & retail | 1997 |
| Traditional Property Solutions Ltd | Construction | 2025 |
| Train Technologies Ltd | Professional & scientific | 2012 |
| Tramore Properties Limited | Real estate | 1987 |
| Trans Global Business Solutions Ltd | Professional & scientific | 2020 |
| Trans Manche Foods Limited | Wholesale & retail | 2005 |
| Transcend Construction Ltd | Construction | 2022 |
| Transhield | Professional & scientific | 2001 |
| Transim Solutions Limited | Wholesale & retail | 2018 |
| Translease Services Limited | Transport & logistics | 2005 |
| Transponder Ltd | Information & communication | 2015 |
| Travega Limited | Other services | 2014 |
| Travel Tailormade Franchise Ltd | Administrative & support | 2011 |
| Travel Trust Association Limited | Professional & scientific | 2007 |
| TRAVELADMIN4U Limited | Administrative & support | 2016 |
| Travelwithzoe Ltd | Administrative & support | 2025 |
| Treats Wholesale Ltd | Wholesale & retail | 2026 |
| Tree Ctrl Ltd | Agriculture & fishing | 2018 |
| Treefrog Design Associates Limited | Professional & scientific | 2003 |