| THE Square Mile Marine Company Limited | Information & communication | 1986 |
| THE Structural Design Office Limited | Professional & scientific | 2007 |
| THE Surrey Public House Ltd | Hospitality | 2018 |
| THE Sweet Wrangler Ltd | Wholesale & retail | 2026 |
| THE TAJ (Orpington) Limited | Hospitality | 2002 |
| THE Tax HUT Limited | Professional & scientific | 2003 |
| THE Thirst Trap Bar Ltd | Hospitality | 2023 |
| THE Trust ME Group Ltd | Extraterritorial | 2019 |
| THE Tudor PUB Company Limited | Hospitality | 2025 |
| THE Twin Cleaning Company Ltd | Administrative & support | 2025 |
| THE Ultimate Boon Ltd | Wholesale & retail | 2023 |
| THE Unexpected Yogi Limited | Other services | 2024 |
| THE Vending Bros Ltd | Wholesale & retail | 2025 |
| THE Waffle Workshop Ltd | Hospitality | 2019 |
| THE Wellness Artist Limited | Wholesale & retail | 2023 |
| THE Wick Nook Ltd | Manufacturing | 2025 |
| THE Wine Shop Ltd | Wholesale & retail | 2022 |
| THE Yummy Foodie Ltd | Hospitality | 2024 |
| Thecary Ltd | Health & social care | 2024 |
| Thecollabhub One Ltd | Professional & scientific | 2025 |
| Thelazysloth Limited | Wholesale & retail | 2025 |
| Themotive Limited | Manufacturing | 2022 |
| Thenextminds Ltd | Information & communication | 2019 |
| Thillai Estates Ltd | Real estate | 2026 |
| Thillai Kovil Estates Ltd | Construction | 2026 |
| Thirty SIX Charlotte Road Limited | Hospitality | 2022 |
| Thomas Dunton Solicitors LLP | | 2020 |
| Thony Stones Ltd | Real estate | 2025 |
| Thornton-Ley Construction Ltd | Construction | 2017 |
| Three Chimneys Consulting Limited | Other services | 2017 |
| Threshers Day Nursery | Education | 2001 |
| Tibix Services Ltd | Other services | 2015 |
| Tier One Global Property Limited | Real estate | 2022 |
| Tiffin Services Limited | Wholesale & retail | 2020 |
| Tiffin Trading Limited | Wholesale & retail | 2019 |
| Tiger PIT Crossfit 2.0 Ltd | Arts & recreation | 2019 |
| Tijami & Co Ltd | Other services | 2018 |
| Tiles Plus Ltd | Wholesale & retail | 2020 |
| Tiletec Contracts Limited | Construction | 2009 |
| Tilly Enterprises Limited | Professional & scientific | 2025 |
| Tilyz AI Ltd | Information & communication | 2024 |
| TIM Croft Flooring Ltd | Administrative & support | 2017 |
| Timeless Cosmetics Ltd | Health & social care | 2024 |
| Timeling Ltd | Other services | 2021 |
| Timeling Services Limited | Other services | 2021 |
| Timetobetter Ltd | Information & communication | 2024 |
| TIN08 Ltd | Transport & logistics | 2021 |
| Tiny Trailblazer Limited | Wholesale & retail | 2025 |
| Tivoli Place Management Company (Ilkley) Limited | Households | 1995 |
| TJ Hire Limited | Administrative & support | 1998 |
| TKA Properties Ltd | Real estate | 2020 |
| TKF Consultancy Ltd | Professional & scientific | 2015 |
| Tklassiq Mini Bumbles Limited | Health & social care | 2025 |
| TLR Fire Doors Limited | Construction | 2021 |
| TLR Fire Protection Limited | Professional & scientific | 2018 |
| TMH Mobile Valeting Limited | Administrative & support | 2021 |
| Tmhair Ltd. | Other services | 2013 |
| TMK Foods Limited | Hospitality | 2019 |
| TMN Contractors Limited | Construction | 2005 |
| TMN Electrical Ltd | Construction | 2018 |
| TN Investment Group Limited | Real estate | 2024 |
| TNR Holdings Ltd | Real estate | 2020 |
| Tokoro Design Consultancy Ltd | Construction | 2017 |
| Tolbex Limited | Construction | 2026 |
| TOM Spencer Design Limited | Other services | 2019 |
| Tom-E Building Services Limited | Construction | 2017 |
| Tombuild Ltd | Construction | 2016 |
| Tomehouse Limited | Wholesale & retail | 2020 |
| Tonbridge Retail Property Ltd | Construction | 2016 |
| Tone of Voice Limited | Professional & scientific | 2011 |
| Tonex Limited | Construction | 2006 |
| Tongue TIE Specialist Ltd | Health & social care | 2025 |
| Tonsor London Ltd | Other services | 2022 |
| TOO Good to Throw Recycling Ltd | Water & waste | 2023 |
| TOO Perky Grinders Ltd | Wholesale & retail | 2025 |
| Top Gardening Ltd | Administrative & support | 2024 |
| Top HAT Logistics Limited | Transport & logistics | 2018 |
| Top Notch Decorators Ltd | Construction | 2022 |
| Top Projects Ltd | Manufacturing | 2024 |
| Topmind Property Ltd | Households | 2021 |
| Topps Services Ltd | Construction | 2023 |
| Topreach Solutions Ltd | Construction | 2026 |
| Topson Alpha Ltd | Real estate | 2024 |
| Topson Holdings Ltd | Financial services | 2023 |
| Total Electric Solutions Holdings Limited | Financial services | 2017 |
| Total Electric Solutions Limited | Construction | 2006 |
| Total Facilities Group Ltd | Financial services | 2019 |
| Total Facilities Recruitment Limited | Administrative & support | 2014 |
| Total Support Services Holdings Limited | Financial services | 2024 |
| Total Support Services Limited | Administrative & support | 1993 |
| Toucan Supplies & Services Ltd | Wholesale & retail | 2021 |
| Touch of Class (UK Ltd) Limited | Hospitality | 2019 |
| Touchstone Recruitment Limited | Administrative & support | 2009 |
| Toulson & Webb Estates Limited | Real estate | 2025 |
| Townfirst Limited | Construction | 1990 |
| TP Labs Ltd | Information & communication | 2026 |
| TPI Property Investments Limited | Real estate | 2023 |
| TPK Developments Ltd | Construction | 2022 |
| Tpmr Retail Ltd | Wholesale & retail | 2024 |
| TQ Maintenance Ltd | Administrative & support | 2023 |