| Tachi Ltd | Professional & scientific | 2023 |
| TAF Global Limited | Information & communication | 2023 |
| Tagg Acquisitions Limited | Financial services | 2026 |
| Tagg Clothing Limited | Wholesale & retail | 2026 |
| Tails on Trails Ltd | Other services | 2023 |
| Taitum Ltd | Health & social care | 2014 |
| Talbot Property Partners Limited | Real estate | 2006 |
| Talentbau Limited | Administrative & support | 2023 |
| Talentxpert Ltd | Information & communication | 2025 |
| Talkcare Services Limited | Health & social care | 2020 |
| Talking Plates Limited | Manufacturing | 2015 |
| Tara Business Services Limited | Administrative & support | 2016 |
| Tarmelia Consulting Ltd | Information & communication | 2015 |
| Tarof Holding Limited | Wholesale & retail | 2020 |
| Taskduk Ltd | Information & communication | 2025 |
| Taskforce Solutions Ltd | Administrative & support | 2023 |
| Taurus Consultancy Services Limited | Professional & scientific | 2017 |
| Tavan Contractors Ltd | Construction | 2020 |
| Taxsolve U.K. Limited | Professional & scientific | 1992 |
| TAY Accountancy Limited | Professional & scientific | 2018 |
| Taylor Wilson Services Ltd | Wholesale & retail | 2018 |
| TBS Inc Limited | Professional & scientific | 2013 |
| TDK UK Limited | Manufacturing | 2000 |
| Teach in Birmingham Limited | Professional & scientific | 2011 |
| Teach in London Limited | Professional & scientific | 2011 |
| Team Brothers 4 YOU Ltd | Construction | 2024 |
| Tech Air Stream Limited | Other services | 2019 |
| Tech Arena Limited | Wholesale & retail | 2023 |
| Techex Europe Limited | Financial services | 1996 |
| Techex Limited | Information & communication | 1972 |
| Techfog (Bracknell) Ltd | Wholesale & retail | 2025 |
| Techfog Wholesale Ltd | Wholesale & retail | 2026 |
| Techlogical Ltd | Information & communication | 2010 |
| Technical Track Coatings Ltd | Manufacturing | 2024 |
| Technichols Resourcing Limited | Administrative & support | 2016 |
| Technitarl Limited | Professional & scientific | 2010 |
| Techno Consultants Limited | Information & communication | 1985 |
| Techno Engineering and Management Consulting Limited | Professional & scientific | 2015 |
| Technogym U.K. Limited | Administrative & support | 1993 |
| Technology Holdings Limited | Extraterritorial | 1989 |
| Technovaprime Ltd | Wholesale & retail | 2024 |
| Techserv Ltd | Construction | 2021 |
| Techtain Ltd | Information & communication | 2025 |
| Techygen Solutions Ltd | Information & communication | 2015 |
| Teddymo Services Limited | Health & social care | 2016 |
| TEE2CARE Limited | Health & social care | 2025 |
| Tego Healthcare Ltd | Other services | 2013 |
| Tego Limited | Real estate | 2018 |
| TEK 2 Productions Ltd | Information & communication | 2020 |
| Tekno Fire Ltd | Construction | 2023 |
| Teksystems Global Services (UK) Limited | Other services | 1998 |
| Tekton Deco and Refurbishment Ltd | Construction | 2019 |
| Tektronix U.K.Limited | Manufacturing | 1952 |
| Telecom Engineering Management Services Ltd | Information & communication | 2016 |
| Teleprompter for Video Ltd | Information & communication | 2025 |
| Tempestas Astrolabe Ltd | Financial services | 2010 |
| Tempestas Development Limited | Professional & scientific | 2024 |
| Tempestas TCU29 Bond Limited | Financial services | 2021 |
| Temples London Limited | Real estate | 2012 |
| Tems Holdings Limited | Real estate | 2022 |
| Tender Crown Ltd | Other services | 2017 |
| Tenere Ltd | Financial services | 2022 |
| Teqpulse Limited | Professional & scientific | 2024 |
| Terawear Ltd | Wholesale & retail | 2025 |
| Teresa Homes Ltd | Real estate | 2022 |
| Terra Renew Solutions Ltd | Construction | 2024 |
| Terrix Ltd | Professional & scientific | 2026 |
| Tessa Tilling Holdings Ltd | Households | 2019 |
| Textile Services Association Limited | Other services | 1920 |
| TG and C Company Limited | Health & social care | 2023 |
| TG Best Limited | Hospitality | 2026 |
| TG Partnership Limited | Professional & scientific | 2023 |
| TGJ Services Limited | Other services | 2003 |
| TGS Business Services Limited | Information & communication | 2015 |
| Thames Technology Limited | Information & communication | 2009 |
| Thames Valley Business Advisors Limited | Professional & scientific | 2004 |
| Thames Valley Catering Equipment Ltd | Professional & scientific | 2021 |
| Thames Valley Cavaliers Limited | Arts & recreation | 2014 |
| Thames Valley Windows LLP | | 2011 |
| Thanet-Ware (Kent) Limited | Manufacturing | 1948 |
| Thanet-Ware Limited | Manufacturing | 1978 |
| Thank YOU and Goodnight Ltd | Information & communication | 2025 |
| Thanksbox Limited | Information & communication | 2013 |
| That Dress Limited | Wholesale & retail | 2017 |
| THE 33 Group Limited | Real estate | 1989 |
| THE Accounts Team Ltd | Professional & scientific | 2010 |
| THE Acoustic Couch Community Centre CIC | Administrative & support | 2016 |
| THE AI Advantage Academy Ltd | Administrative & support | 2025 |
| THE Artistic Gardener Ltd | Administrative & support | 2014 |
| THE Ascot Builder Limited | Construction | 2020 |
| THE Barber Shop Bracknell Limited | Other services | 2018 |
| THE Better Conversations Foundation Ltd | Other services | 2024 |
| THE Big Thumb 168 Ltd | Hospitality | 2026 |
| THE Big Trade Planner Limited | Wholesale & retail | 2025 |
| THE Bizbook Ltd | Administrative & support | 2022 |
| THE Bounce Forge Ltd | Information & communication | 2024 |
| THE Braccan Health Primary Care Network Limited | Health & social care | 2021 |
| THE Chartered Institute of Building Benevolent Fund | Other services | 1992 |
| THE Checkmate Collective Ltd | Wholesale & retail | 2025 |
| THE Clean Team (Southern) Limited | Administrative & support | 2005 |