| Thickbroom Enterprise CIC | Administrative & support | 2025 |
| Think Success UK Limited | Professional & scientific | 2013 |
| Think Talent Ltd | Administrative & support | 2024 |
| Thinksmallcell Ltd. | Information & communication | 1997 |
| Third EYE Fitness Limited | Arts & recreation | 2018 |
| Third Square Ltd | Administrative & support | 2016 |
| Third Training Space Ltd. | Arts & recreation | 2017 |
| Thirst Essex Ltd | Manufacturing | 2023 |
| Thirsty Sloth Productions Ltd | Information & communication | 2025 |
| Thirty Seven Limited | Real estate | 2021 |
| THL Consultants Ltd | Information & communication | 2022 |
| Thomas Cottages Residents Association Limited | Households | 2000 |
| Thomas Dempsey Ltd | Administrative & support | 2016 |
| Thomas Emlyn Ltd | Professional & scientific | 2021 |
| Thomas HOY Properties Ltd | Real estate | 2026 |
| Thomas Leisure Limited | Wholesale & retail | 2019 |
| Thomas Tech Ltd | Construction | 2015 |
| Thompson Brothers Design & Print Limited | Arts & recreation | 2019 |
| Thorndon Properties Limited | Professional & scientific | 2003 |
| Thorndon Security Ltd | Administrative & support | 2016 |
| Thornwood Associates Limited | Professional & scientific | 2019 |
| Thorogood Newco Limited | Wholesale & retail | 2022 |
| Thorogoods Ball Throwers Ltd | Manufacturing | 2010 |
| Thorogoods Haylage Limited | Hospitality | 2004 |
| Thoroughgood Engineering Ltd | Construction | 2022 |
| Thoth Hermes T&P Limited | Information & communication | 2018 |
| Thracian People Ltd | Transport & logistics | 2026 |
| Threat Intelligence Bureau Ltd | Information & communication | 2022 |
| Three Corners Motor Co Limited | Wholesale & retail | 2024 |
| Three Counties Vending Ltd | Wholesale & retail | 2020 |
| Three Lions Developments Ltd | Construction | 2021 |
| Three River Kitchens & Interiors Ltd | Manufacturing | 2022 |
| Three Rivers Joinery Limited | Manufacturing | 2019 |
| Thrishul Foods Limited | Wholesale & retail | 2025 |
| THRIVEBEYOND9TO5 Ltd | Education | 2025 |
| Thumb Soldiers Ltd | Manufacturing | 2022 |
| Thurrock Hammers Limited | Arts & recreation | 2019 |
| Thurrock Investment Properties Limited | Wholesale & retail | 1981 |
| THV Environmental Services Limited | Professional & scientific | 2008 |
| Tiara Publishing Ltd | Information & communication | 2020 |
| Tidal Change Management Limited | Professional & scientific | 2017 |
| Tides Digital Limited | Administrative & support | 2014 |
| Tidev Ltd | Extraterritorial | 2018 |
| Tiers to Business Freedom Ltd | Professional & scientific | 2026 |
| Tiger Bay Design Limited | Arts & recreation | 2018 |
| Tiger India Limited | Hospitality | 2023 |
| Tiger S Lounge Ltd | Hospitality | 2025 |
| Tigercub Consulting Ltd | Professional & scientific | 2018 |
| Tikka Corner Ltd | Hospitality | 2025 |
| Tilesandstonedirect Limited | Wholesale & retail | 2012 |
| Tillit Consultancy Ltd | Information & communication | 2024 |
| Tillit Foods Ltd | Wholesale & retail | 2024 |
| Tillit Group Ltd | Wholesale & retail | 2022 |
| TIM Cars Limited | Wholesale & retail | 2016 |
| TIM Matthews Associates Limited | Professional & scientific | 1988 |
| Timber House Ltd | Construction | 2023 |
| Time & Light Studios Ltd | Information & communication | 2022 |
| Time Barber Ltd | Other services | 2023 |
| Time Design Consultancy Limited | Professional & scientific | 2017 |
| Time Machine Fashion Watches Ltd | Wholesale & retail | 2024 |
| Time to File Limited | Professional & scientific | 2013 |
| Time to Heal Ltd | Health & social care | 2017 |
| Time to Run Limited | Wholesale & retail | 2006 |
| Timeless Allure Ltd. | Other services | 2017 |
| Timeless Atelier Ltd | Manufacturing | 2025 |
| Timeless Rides Ltd | Transport & logistics | 2025 |
| Timfaith Limited | Construction | 2014 |
| Timpson's Lane Management Company Ltd | Professional & scientific | 2014 |
| Tinatech Limited | Professional & scientific | 2003 |
| Tinkies Boutique Limited | Wholesale & retail | 2021 |
| Tinmouse Animation Studio Ltd | Information & communication | 2016 |
| Tino Travels Ltd | Administrative & support | 2024 |
| Tiny Footprint Ltd | Health & social care | 2025 |
| Tiny Ghost Records Ltd | Arts & recreation | 2022 |
| Tiny Treasures - Castings Limited | Manufacturing | 2016 |
| Tiny Trouble Ltd | Wholesale & retail | 2026 |
| Tipping Turtle Limited | Real estate | 2017 |
| Tipsy Tails Ltd | Hospitality | 2023 |
| Tiptoe Toys Ltd | Manufacturing | 2024 |
| Tiptree Construction Limited | Construction | 2025 |
| Tirlan Ltd | Information & communication | 2016 |
| Tiro Associates Limited | Administrative & support | 1999 |
| Tiro Contracts Limited | Administrative & support | 2017 |
| Tiro Holdings Ltd | Real estate | 2024 |
| Tisak Homes Limited | Real estate | 2024 |
| Tita (Hobart) Limited | Real estate | 2025 |
| Titanium Leisure Limited | Arts & recreation | 2022 |
| Titobychefyemss Ltd | Manufacturing | 2024 |
| Titu's Kitchen Dine in Limited | Hospitality | 2025 |
| Titu's Kitchen Ltd | Hospitality | 2020 |
| TJ Holdings London Ltd | Wholesale & retail | 2026 |
| TJB Environmental Services Limited | Administrative & support | 2016 |
| TJB Homes Ltd | Real estate | 2018 |
| TJN Accountancy Limited | Professional & scientific | 2021 |
| TJN Accounts Limited | Professional & scientific | 2021 |
| TK SERVICES2015 Ltd | Health & social care | 2015 |
| TK Stud Ltd | Agriculture & fishing | 2025 |
| TKL Medical Ltd | Health & social care | 2025 |
| TKO Studio and Spa Ltd | Other services | 2021 |
| Tkps Group Ltd | Wholesale & retail | 2025 |