| TIG Property Services Limited | Construction | 2021 |
| Tigra Transport Ltd | Transport & logistics | 2026 |
| Tiksnow Construction Ltd | Construction | 2018 |
| Tiktok Properties Ltd | Real estate | 2024 |
| Tilly Support Services CIC | Administrative & support | 2024 |
| Timi Care Limited | Health & social care | 2025 |
| Timotal Construction Ltd | Construction | 2020 |
| Tipi Homes Limited | Hospitality | 2024 |
| Tiromy Ltd | Wholesale & retail | 2023 |
| Tismac Consulting Ltd | Professional & scientific | 2026 |
| Titan Fuel Solutions Ltd | Wholesale & retail | 2025 |
| Titan London Builders Ltd | Construction | 2022 |
| Titan Plumbing Ltd | Construction | 2016 |
| Titan Property Management Ltd | Real estate | 2005 |
| Tittann Ltd | Professional & scientific | 2023 |
| Tiva Medical Consultancy Ltd | Other services | 2025 |
| Tj's Experience Ltd | Health & social care | 2013 |
| TK & Kavin Ltd | Professional & scientific | 2022 |
| TK Ecommerce PVT Ltd | Wholesale & retail | 2022 |
| TK Essentials Ltd | Wholesale & retail | 2026 |
| Tlnm Services Limited | Professional & scientific | 2026 |
| Tlsstore Limited | Wholesale & retail | 2022 |
| TM Boxing Limited | Arts & recreation | 2018 |
| TM Financial Services Ltd | Professional & scientific | 2010 |
| TMB Coaching and Wellness Services Ltd. | Public administration | 2023 |
| TMD Developments Limited | Information & communication | 2015 |
| Tmonie Records Ltd | Information & communication | 2019 |
| TNK Resources Ltd | Professional & scientific | 2010 |
| TNT Investment Ltd | Real estate | 2024 |
| Todd Transport Limited | Transport & logistics | 2005 |
| Together WE Ride CIC | Other services | 2021 |
| Tolani Alaba Ltd | Health & social care | 2014 |
| Toledo Woodhead Springs Limited | Extraterritorial | 1937 |
| Tolwood Engineering Limited | Extraterritorial | 1953 |
| Tommy Fortnite Ltd | Information & communication | 2021 |
| Tonda Holdings Ltd | Financial services | 2022 |
| Tonven Ltd | Construction | 2024 |
| Tony Burton Consulting Limited | Professional & scientific | 2012 |
| Tony Doan Ltd | Other services | 2017 |
| Tony's Consultancy Services Ltd | Professional & scientific | 2025 |
| Tony's Delicatessen ( London ) Ltd | Hospitality | 2024 |
| Toomey Holdings Limited | Administrative & support | 2017 |
| Tooting Construction & Handyman Ltd | Construction | 2019 |
| Tooting Transport Ltd | Transport & logistics | 2023 |
| Top END Homes Limited | Construction | 2017 |
| Top Energy Solutions Ltd | Administrative & support | 2015 |
| Top Fashion Hair and Beauty Cosmetics Ltd | Wholesale & retail | 2014 |
| Top Grade Property Ltd | Real estate | 2023 |
| Topas Management UK Ltd | Professional & scientific | 2023 |
| Topcrete Limited | Manufacturing | 1990 |
| Topgrade Solutions Ltd | Construction | 2015 |
| Toppertrain Ltd | Education | 2025 |
| Torto Investment Limited | Households | 2025 |
| Touseef Mansoor Group Ltd | Wholesale & retail | 2026 |
| TPG Promotions Ltd | Professional & scientific | 2010 |
| TR Build Ltd | Construction | 2016 |
| Traders Connections Group Ltd | Wholesale & retail | 2022 |
| Tradewise Europe Ltd | Wholesale & retail | 2020 |
| Trading Modelling Ltd | Wholesale & retail | 2024 |
| Trafalgar Park Properties Limited | Real estate | 2011 |
| TRAIN2INSPIRE Consultancy Ltd | Professional & scientific | 2018 |
| Trams Consultancy Ltd | Professional & scientific | 2025 |
| Tranquil Housing Ltd | Real estate | 2024 |
| Transform Counselling Community Interest Company | Health & social care | 2015 |
| Transformation Christian Centre | Other services | 2018 |
| Transitflex UK Ltd | Transport & logistics | 2009 |
| Travel Bookerz Limited | Hospitality | 2017 |
| Travel on Peak Ltd | Administrative & support | 2025 |
| Travelsun Ltd | Wholesale & retail | 2025 |
| Trbd Ltd | Construction | 2018 |
| Treadmore Limited | Real estate | 2016 |
| Treatexwallcoatings Ltd | Construction | 2014 |
| Trek Solutions Limited | Health & social care | 2018 |
| Trela Transport Ltd | Transport & logistics | 2025 |
| Trendzen Limited | Wholesale & retail | 2024 |
| TRF Group Limited | Hospitality | 2025 |
| Triada Building Ltd | Construction | 2020 |
| Triangulate Limited | Wholesale & retail | 2005 |
| Trichozen Ltd | Health & social care | 2025 |
| Tricity Properties Limited | Real estate | 2025 |
| Trilogy Tech Limited | Professional & scientific | 2025 |
| TRIN22 Ltd | Public administration | 2022 |
| Trinit.Emassage Ltd | Other services | 2023 |
| Trinity Design & Build (London) Ltd | Construction | 2025 |
| Trinity Tuition Centre Ltd | Education | 2024 |
| Trio Offset Limited | Manufacturing | 1985 |
| Triple K'S Limited | Health & social care | 2019 |
| Trishoolin House Ltd | Wholesale & retail | 2022 |
| Triwill Group UK Ltd | Manufacturing | 2022 |
| Triz Limited | Wholesale & retail | 2026 |
| Trodal Care Limited | Health & social care | 2022 |
| Trodosports Limited | Information & communication | 2025 |
| Trosym Ltd | Wholesale & retail | 2021 |
| Trst Ltd | Hospitality | 2025 |
| Trst Mathu Success Ltd | Households | 2018 |
| Tru-Grit Limited | Extraterritorial | 1982 |
| Trubrite Limited | Extraterritorial | 1935 |
| True Scaffolding Limited | Construction | 2003 |
| True Scaffolding Surrey Ltd | Construction | 2020 |
| True Supply Limited | Wholesale & retail | 2025 |