| Thomson Property Group Holdings Limited | Financial services | 2025 |
| Thomson Property Group Limited | Real estate | 2025 |
| Thorn Electric MK Limited | Construction | 2013 |
| Thorn Legacy Film Limited | Information & communication | 2013 |
| Thornborough Holdings Ltd | Real estate | 2024 |
| Thorne House Yeovil Limited | Construction | 2018 |
| Thorne Sports Limited | Arts & recreation | 2020 |
| Thornes Management (NO 1) Limited | Households | 1991 |
| Thornes Management (NO.2) Limited | Households | 1992 |
| Thornley Legal Services Limited | Professional & scientific | 2023 |
| Thornton Coach Houses Management Company Limited | Households | 2000 |
| Thornton Hundred Holdings Limited | Financial services | 2021 |
| Thornton Hundred Motorcycles Limited | Wholesale & retail | 2020 |
| Thorntree Estates Ltd. | Real estate | 1993 |
| Thorough-Lee Clean Ltd | Administrative & support | 2025 |
| Thorpe Bay Letting Ltd | Real estate | 2025 |
| Thoulstone Barns Limited | Construction | 2020 |
| Thoulstone Farm Limited | Construction | 2019 |
| Thps Homes Limited | Real estate | 2022 |
| Thrave Ltd | Wholesale & retail | 2026 |
| Three Aces Publishing Ltd | Information & communication | 2016 |
| Three Bridge Properties Limited | Real estate | 2019 |
| Three Counties Commercial Services Ltd | Construction | 2026 |
| Three Counties Group Ltd | Other services | 2022 |
| Three Counties Honey Ltd | Agriculture & fishing | 2022 |
| Three Counties Hospitality Limited | Hospitality | 2026 |
| Three Counties Tyre Services LLP | | 2006 |
| Three DOT Gateway Ltd | Wholesale & retail | 2024 |
| Three External Marketing Ltd | Professional & scientific | 2025 |
| Three Green Trees Limited | Professional & scientific | 2024 |
| Three Keys Mortgage Consultants Ltd | Financial services | 2018 |
| Three Locks Golf Club Ltd | Arts & recreation | 2000 |
| Three Rooms Design Ltd | Professional & scientific | 2020 |
| Three-Fold Resource Consultancy Ltd | Education | 2018 |
| Threebyone Limited | Information & communication | 2015 |
| Threes Leaving Limited | Wholesale & retail | 2024 |
| Thrift Activity Farm Limited | Education | 2019 |
| Thrift Farm Day Nursery & Pre-School Limited | Health & social care | 2025 |
| Thriftylift Limited | Manufacturing | 1991 |
| Thrive Beyond Limited | Health & social care | 2026 |
| Thrive! Growing Business Limited | Professional & scientific | 2012 |
| Thrivemetrics Limited | Professional & scientific | 2025 |
| Thriving Culture Ltd | Professional & scientific | 2023 |
| Throne Room Glory Ministries Ltd. | Other services | 2020 |
| Through the Roof Events Limited | Other services | 2025 |
| Thrs Rewards Ltd | Professional & scientific | 2025 |
| Thulium Argent Ltd | Financial services | 2015 |
| Thurairaji Ltd | Hospitality | 2024 |
| TI Studio Limited | Information & communication | 2014 |
| Tialoc Limited | Professional & scientific | 2018 |
| Tian HAO Cultura Media Ltd | Information & communication | 2025 |
| Tian YU Culture Ltd | Professional & scientific | 2025 |
| Tiao LIN Ltd. | Wholesale & retail | 2025 |
| Tiberium Limited | Information & communication | 2004 |
| Tibi Hand Car Wash Ltd | Other services | 2017 |
| Tibitrans Ltd | Transport & logistics | 2019 |
| TIC Construction RO Ltd | Construction | 2021 |
| TIC Remit Limited | Professional & scientific | 2017 |
| Tichaz Private Ltd | Health & social care | 2019 |
| Tickeat Ltd | Hospitality | 2015 |
| Ticket Dons Ltd | Administrative & support | 2024 |
| Tickets.Com Limited | Information & communication | 1988 |
| Tickford Street Convenience Store Limited | Wholesale & retail | 2018 |
| Tictac Technologies Limited | Information & communication | 2006 |
| Tide Developments (Lewisham) Limited | Construction | 2018 |
| Tidyquant Ltd | Information & communication | 2017 |
| Tie-Stone Investments Limited | Financial services | 2016 |
| Tie-Stone Limited | Administrative & support | 2016 |
| Tier 1 Construction Group Ltd. | Extraterritorial | 2023 |
| Tier Lounge Ltd | Hospitality | 2015 |
| Tier Pro Limited | Wholesale & retail | 2021 |
| Tier Stack Limited | Information & communication | 2023 |
| Tiers of Joy Bakery Ltd | Hospitality | 2025 |
| Tiftys Limited | Wholesale & retail | 2022 |
| Tiger Watch Security Ltd | Administrative & support | 2015 |
| Tigerz Investments Ltd | Financial services | 2025 |
| Tiggi Limited | Information & communication | 2016 |
| Tigue Tiling & Flooring Ltd | Construction | 2025 |
| Tihonov-Trans Ltd | Transport & logistics | 2021 |
| TIK TAK Childcare Ltd | Education | 2010 |
| Tiki Implements Ltd | Real estate | 2020 |
| Tiktak Investment Limited | Households | 2021 |
| TIKTOKSHOPNO1 Ltd | Wholesale & retail | 2025 |
| Tildium Ltd | Information & communication | 2016 |
| Tile Factory Outlet Ltd | Wholesale & retail | 2024 |
| Tile Master MK Ltd | Wholesale & retail | 2022 |
| Tilecart UK Ltd | Wholesale & retail | 2025 |
| Tilestogo Ltd | Manufacturing | 2024 |
| Tillett and SON Property Services Limited | Construction | 2017 |
| Tillies Ltd | Construction | 2025 |
| Tilsworth Land and Development Limited | Construction | 2014 |
| TIM Brinton Cars Limited | Real estate | 1972 |
| TIM Business Multiservices Ltd | Information & communication | 2020 |
| TIM Law Consulting Limited | Professional & scientific | 2025 |
| TIM Machon Origin Tree Surgery Limited | Administrative & support | 2025 |
| TIM Palmer Limited | Real estate | 2019 |
| TIM Searle Animation Limited | Administrative & support | 2021 |
| TIM Technologies Ltd | Information & communication | 2020 |
| Timarnie Media Limited | Information & communication | 2012 |
| Timasa Limited | Health & social care | 2018 |