| TK Turnaround Care Ltd | Health & social care | 2018 |
| Tkdetailedit Ltd | Wholesale & retail | 2025 |
| TKS & SON Ltd | Transport & logistics | 2019 |
| TL UK Investment Ltd | Real estate | 2026 |
| TLD Industries Ltd | Construction | 2020 |
| TLH Ventures Ltd | Administrative & support | 2022 |
| TM Advertising Limited | Arts & recreation | 2018 |
| TMP the Mortgage People Ltd | Financial services | 2005 |
| Tocilla Car Wash Ltd | Other services | 2019 |
| Toddlerz Day Nursery Limited | Health & social care | 2014 |
| Toddz Moppz Limited | Administrative & support | 2015 |
| Toddz Proppz Limited | Financial services | 2018 |
| TOM Francis Tree Services Ltd | Administrative & support | 2024 |
| TOM Fray Equestrian Coaching Ltd | Administrative & support | 2017 |
| TOM Graham Homes Ltd | Construction | 2016 |
| TOM J Robinson Ltd | Professional & scientific | 2025 |
| TOM Lomas Livestock Consultants Ltd | Agriculture & fishing | 2013 |
| TOM Mills Painting and Decorating Ltd | Construction | 2021 |
| Tomasz Piwkowski Transport Limited | Transport & logistics | 2013 |
| Tomige Limited | Real estate | 2009 |
| Tomige Stamford Ltd | Real estate | 2020 |
| Toni's Trucking Limited | Transport & logistics | 2016 |
| Tony Hughes Consulting Ltd | Professional & scientific | 2020 |
| Tonys Fireworks Limited | Wholesale & retail | 2017 |
| Tool Engineering Limited | Manufacturing | 2015 |
| Toomee Limited | Information & communication | 2023 |
| Top Banana Couriers Limited | Transport & logistics | 2017 |
| Top Consulting Services Ltd | Administrative & support | 2022 |
| Top Dog Custom Cages Ltd | Manufacturing | 2025 |
| Top Model Management Ltd | Professional & scientific | 2024 |
| Topcell Pharma Limited | Wholesale & retail | 2017 |
| Topmobileparts Ltd | Wholesale & retail | 2025 |
| Toro Steaks (Rothwell) Limited | Hospitality | 2025 |
| Torrex Group Ltd | Construction | 2026 |
| Total Accessory Maintenance Repair & Overhaul Limited | Transport & logistics | 2004 |
| Total Accounting (Northants) Limited | Professional & scientific | 2023 |
| Total Managed Document Solutions Limited | Administrative & support | 2019 |
| Total Managed Document Solutions London Limited | Administrative & support | 2019 |
| Total Managed Document Solutions Midlands Limited | Manufacturing | 2013 |
| Total Moisture Control UK Ltd | Construction | 2025 |
| Totally Wild Food Ltd | Manufacturing | 2017 |
| Totang Jewellers Limited | Other services | 2003 |
| Totnes Property 1 Ltd | Real estate | 2017 |
| Totus Care Ltd | Health & social care | 2013 |
| Touch Shenstone Ltd | Real estate | 2014 |
| Touchless Tech Ltd | Professional & scientific | 2023 |
| Toureks Ltd | Transport & logistics | 2020 |
| Touring Metal Drinks Limited | Manufacturing | 2025 |
| Towns on the Web Ltd | Information & communication | 1997 |
| Townsweb Archiving Limited | Information & communication | 2006 |
| Toxp Ltd | Agriculture & fishing | 2025 |
| TPW Process Installations Limited | Manufacturing | 2017 |
| Track IT NOW Limited | Administrative & support | 2007 |
| Trade Admin Solutions Limited | Public administration | 2025 |
| Trade Guard UK Limited | Information & communication | 2025 |
| Trafalgar Residential Investments Ltd | Real estate | 2021 |
| Trafalgar Sourcing Ltd | Real estate | 2024 |
| Trainor Properties Limited | Real estate | 2025 |
| Trak Property Limited | Real estate | 2021 |
| Transgarant Ltd | Wholesale & retail | 2019 |
| Transglobal Imperium Ltd | Transport & logistics | 2026 |
| Transilvania Ltd | Hospitality | 2020 |
| Travelling Tutors Ltd | Education | 2025 |
| Traynor CS Limited | Construction | 2024 |
| Trendxglobal Ltd | Professional & scientific | 2019 |
| Trendy Beds Ltd | Wholesale & retail | 2024 |
| Trevor Hill Holdings Limited | Financial services | 2021 |
| Triangular Care Services Ltd | Health & social care | 2001 |
| Triangular Mango Ltd | Real estate | 2020 |
| Tribe Wellbeing Ltd | Wholesale & retail | 2019 |
| Trident PUB Company Limited | Hospitality | 2020 |
| Trinity Care Homes Limited | Health & social care | 2017 |
| Trinity Education Support Limited | Education | 2015 |
| Trinwin Ltd | Arts & recreation | 2025 |
| Triple 777 Services Ltd | Wholesale & retail | 2020 |
| Triple H Print Trading AS RTH Printing Ltd | Manufacturing | 2016 |
| Triple X Services Ltd | Wholesale & retail | 2025 |
| Tritoma Construction Products (UK) Limited | Wholesale & retail | 2024 |
| Truck Tyres Direct Limited | Wholesale & retail | 2023 |
| Truckers Logistics Ltd | Administrative & support | 2017 |
| Truckovation Ltd | Manufacturing | 2015 |
| True U Limited | Professional & scientific | 2018 |
| Truemix Concrete Limited | Manufacturing | 2025 |
| Truerod Limited | Households | 1988 |
| Trust Delivery Ltd | Transport & logistics | 2023 |
| Trust US Services Limited | Health & social care | 2025 |
| TTM Green Ltd | Construction | 2024 |
| Turbine Motor Works Ltd | Transport & logistics | 2002 |
| Turf Management Systems Limited | Extraterritorial | 1974 |
| Turfland Farms Limited | Agriculture & fishing | 2009 |
| TURN38 Ltd | Real estate | 2021 |
| Turner Plumbing and Heating Limited | Construction | 2023 |
| Tusks Healthcare Services Ltd | Health & social care | 2022 |
| Tutektrans Ltd | Administrative & support | 2017 |
| Tuts Consultancy Limited | Professional & scientific | 2024 |
| Tuts Training Limited | Education | 2024 |
| Twelftree Ltd | Professional & scientific | 2019 |
| Twin Busch UK Ltd | Wholesale & retail | 2016 |
| TWM Sports Ltd | Arts & recreation | 2025 |
| Two Beams Ltd | Real estate | 2022 |