| T H Maintenance Ltd | Administrative & support | 2013 |
| T M International Search Limited | Administrative & support | 2011 |
| T M S Property Developments Limited | Real estate | 2024 |
| T Nathaniel Property Group Ltd | Real estate | 2022 |
| T Threat Theatre Arts LLP | | 2023 |
| T&G POP Ltd | Hospitality | 2025 |
| T'S Hair Lounge Limited | Wholesale & retail | 2025 |
| T. Higgins Ltd | Professional & scientific | 2007 |
| T. M. S. Mechanical Services Limited | Construction | 2018 |
| T.A. Plumbing & Heating Supplies Limited | Transport & logistics | 1987 |
| T.C Rigging Limited | Arts & recreation | 2010 |
| T.C.S. Designs Limited | Manufacturing | 2006 |
| T.D.A Care Solutions Ltd | Professional & scientific | 2024 |
| T.Mileham & Sons Limited | Real estate | 1933 |
| T.R.I.L. Ltd | Real estate | 2017 |
| T.S Sports Management Ltd | Arts & recreation | 2009 |
| T2PM Ltd | Professional & scientific | 2014 |
| T4C Contractors Ltd | Construction | 2019 |
| T7 Holdings Limited | Financial services | 2023 |
| TA Risk Consultancy Ltd | Financial services | 2025 |
| TA Transformation Projects Limited | Professional & scientific | 2026 |
| Tabledrop Limited | Information & communication | 2020 |
| Tabors Hill Limited | Construction | 2025 |
| TAC Partners Limited | Professional & scientific | 2006 |
| Tachana Limited | Professional & scientific | 2014 |
| Tact FM Limited | Professional & scientific | 2016 |
| Tactical Chameleon Airsoft Ltd | Arts & recreation | 2025 |
| Tada Aesthetics & Spa Ltd | Other services | 2024 |
| Tada Healthcare Services Ltd | Health & social care | 2021 |
| TAG Building Consultants Ltd | Professional & scientific | 2019 |
| TAG Pharma Ltd | Professional & scientific | 2022 |
| Taganam Limited | Real estate | 2012 |
| Talem Associates Limited | Administrative & support | 2014 |
| Talentu Group Limited | Administrative & support | 2015 |
| Talking Interiors Ltd | Manufacturing | 2023 |
| Tallann Recruitment Ltd | Administrative & support | 2020 |
| Tallsingles Limited | Information & communication | 2013 |
| Talon Group Limited | Administrative & support | 2025 |
| Talostek Limited | Information & communication | 2024 |
| Tamar Property Investment Ltd | Real estate | 2023 |
| Tamid Zivah LLP | | 2014 |
| Tampra Properties Ltd | Real estate | 2023 |
| Tampra Services Ltd | Information & communication | 2018 |
| TAN HUT Brentwood Ltd | Other services | 2025 |
| Tank and Container Services Limited | Transport & logistics | 2010 |
| Tankd Fitness Ltd | Health & social care | 2021 |
| Tanning @ Hanz & Tanz Limited | Other services | 2009 |
| Tara-Taylor Travel Management Limited | Other services | 2016 |
| Tarantino Limited | Hospitality | 1999 |
| Tarbert Limited | Administrative & support | 2006 |
| Tarbill Limited | Real estate | 1987 |
| Target Finishers Ltd | Construction | 2019 |
| Tari Investments Limited | Real estate | 2023 |
| Tari Vets Limited | Professional & scientific | 2016 |
| Tarrant Electrical Limited | Construction | 2014 |
| TAS Building Services (UK) Ltd | Construction | 2008 |
| TAS Ventures Ltd | Wholesale & retail | 2025 |
| Tashas Holdings Ltd | Professional & scientific | 2019 |
| Tattenhoe Park Residents Management Company Limited | Households | 2022 |
| Tattoo Courses Limited | Education | 2026 |
| Tattoo Hygiene Limited | Health & social care | 2026 |
| Taumarunui Investment LLP | | 2017 |
| Taurus Construction (UK) Limited | Construction | 2006 |
| Taurus Support Services Ltd | Administrative & support | 2018 |
| Tavershams Limited | Wholesale & retail | 2013 |
| Tawny Grove (Great Chalks) Management Company Limited | Households | 2020 |
| Taxac Ltd | Professional & scientific | 2024 |
| Taylor French Developments Limited | Construction | 2005 |
| Taylor Johnson Ltd | Real estate | 2018 |
| Taylor Maid Cleaning Ltd | Administrative & support | 2025 |
| Taylor Oaks Construction Ltd | Construction | 2025 |
| Taylor Project Services LLP | | 2009 |
| Taylor Wines Essex Limited | Wholesale & retail | 2025 |
| Taylor's Car Solutions Ltd. | Other services | 2019 |
| Taylor-Brooke Construction and Landscaping Ltd | Professional & scientific | 2026 |
| Taylor/Webb Ltd | Administrative & support | 2015 |
| TBK House Ltd | Hospitality | 2023 |
| TCD Tree Surgery Ltd | Administrative & support | 2007 |
| TCM Plumbing & Heating Limited | Construction | 2017 |
| TDA Global Trade Ltd | Wholesale & retail | 2020 |
| TDH Holdings Limited | Financial services | 2019 |
| TDK Plumbing & Heating Ltd | Construction | 2026 |
| Tea Cloud Ltd | Wholesale & retail | 2025 |
| Teaching Walkthrus International Ltd | Information & communication | 2021 |
| Team Craft Tackle Limited | Agriculture & fishing | 2016 |
| Team Gene Ltd | Health & social care | 2022 |
| Teamtickets Limited | Wholesale & retail | 2018 |
| Tech Solutions and Advisory Limited | Information & communication | 2023 |
| Techgets Limited | Wholesale & retail | 2020 |
| Techloyce Limited | Information & communication | 2013 |
| Technical GAS Heating & Plumbing Ltd | Construction | 2019 |
| Technical Overseas Services Limited | | 1982 |
| Technofocus Consulting Ltd | Information & communication | 2015 |
| Technogenius Ltd. | Information & communication | 2015 |
| Techsiri Ltd | Information & communication | 2024 |
| Techspress Limited | Wholesale & retail | 2019 |
| Teckraft Limited | Information & communication | 2021 |
| Tecno Accessories Limited | Wholesale & retail | 2024 |
| Tehcom Ltd | Construction | 2021 |
| TEK Property Ltd | Other services | 2015 |