| TMM Healthcare Ltd | Health & social care | 2016 |
| TMP Agricultural Limited | Agriculture & fishing | 2025 |
| TMP Brands Ltd | Wholesale & retail | 2022 |
| TMP Technologies Limited | Information & communication | 2018 |
| Tmpe Ltd | Professional & scientific | 2024 |
| TMS Direct Ltd | Administrative & support | 2025 |
| TMS Industrial Services Ltd | Construction | 2024 |
| TMS Managing Services Ltd | Professional & scientific | 2010 |
| TN Catering Limited | Hospitality | 2019 |
| TN LOU Service Limited | Professional & scientific | 2023 |
| Tnjn Properties Limited | Professional & scientific | 2010 |
| TNW Limited | Professional & scientific | 2015 |
| TOD Consulting Limited | Information & communication | 2026 |
| Today Holdings Ltd | Financial services | 2025 |
| Todd Milburn Limited | Administrative & support | 2023 |
| Todd Milburn Partnership Limited | Administrative & support | 2008 |
| Todd Offshore Ltd | Manufacturing | 2016 |
| Todds Building Services Ltd | Extraterritorial | 2023 |
| Togama Limited | Real estate | 2022 |
| Together WE Flourish Ltd | Health & social care | 2025 |
| Tokoro Food Ltd | Hospitality | 2023 |
| Tolch Maritime Services Ltd | Transport & logistics | 2025 |
| Tolent Construction Limited | Construction | 1989 |
| Tolent Homes Limited | Real estate | 1993 |
| Tolent Solutions Limited | Construction | 2007 |
| TOM Brown Ceramics Limited | Construction | 2003 |
| TOM Care Maidens Ltd | Health & social care | 2018 |
| TOM Kelly Neuropsychology Limited | Health & social care | 2022 |
| TOM Prichard Doctor Services Ltd | Health & social care | 2021 |
| TOM Tappin,Limited | Administrative & support | 1939 |
| Tomant Ltd | Hospitality | 2020 |
| Tomlinson's Cafe and Bunkhouse Limited | Hospitality | 2010 |
| Tommee Tippee Limited | Extraterritorial | 1982 |
| Tommy's Collective Ltd | Hospitality | 2025 |
| Tomorrows World Automotive Ltd | Wholesale & retail | 2011 |
| Tomrimmerdesign Ltd | Manufacturing | 2023 |
| Tondano Consulting Limited | Professional & scientific | 2013 |
| Tong Properties Limited | Real estate | 2019 |
| Tonkin Town Limited | Hospitality | 2023 |
| Tony Long Ceilings and Partitions Ltd | Construction | 2018 |
| Tony MAC Limited | Wholesale & retail | 2015 |
| Tony Quinn Drilling Limited | Administrative & support | 2007 |
| Tony Saint Ltd | Arts & recreation | 2010 |
| TOO Jazzy Holdings Ltd | Wholesale & retail | 2018 |
| Tool Star Ltd | Wholesale & retail | 2019 |
| Toon Cars Ltd | Transport & logistics | 2024 |
| Toon Distribution UK Ltd | Wholesale & retail | 2020 |
| Toon Eats Limited | Hospitality | 2022 |
| Toon Food Ltd | Extraterritorial | 2025 |
| Toon KIT Collector Ltd | Wholesale & retail | 2024 |
| Toon Lets Limited | Real estate | 2022 |
| Toon Property Services Limited | Real estate | 2023 |
| Toon Repair & Vape Hub Co Limited | Wholesale & retail | 2026 |
| Toon Retail Ltd | Wholesale & retail | 2025 |
| Toon Takeaway NE1 Limited | Hospitality | 2026 |
| Toon Tech NE Ltd | Wholesale & retail | 2026 |
| Top & Jeffries Limited | Professional & scientific | 2002 |
| Top Dog Hospitality Services Ltd | Hospitality | 2018 |
| Top Drawer Fitted Furniture Limited | Construction | 2008 |
| Top Edge Cleaning Services Ltd | Administrative & support | 2025 |
| Top Enhancement Beauty Academy Limited | Other services | 2019 |
| Top Gear Bathrooms Limited | Wholesale & retail | 2008 |
| Top HAT Leisure Limited | Hospitality | 2015 |
| Top OFF Limited | Manufacturing | 2025 |
| Top Shop (NE) Ltd | Wholesale & retail | 2025 |
| Top Speed Service Ltd | Wholesale & retail | 2024 |
| Top Star Pro Ltd | Hospitality | 2025 |
| Topaaz Property Ltd | Real estate | 2025 |
| Topaz Virtual Productions (TVP) Ltd | Information & communication | 2021 |
| Topcarsbrands Ltd | Wholesale & retail | 2023 |
| Topchoice Mart Ltd | Wholesale & retail | 2025 |
| Topmezze Newcastle Ltd | Hospitality | 2024 |
| Topo Projects Limited | Construction | 2025 |
| Topolino Restaurant Ltd | Hospitality | 2025 |
| Topscorer Ltd | Wholesale & retail | 2026 |
| Topside Group Limited | Construction | 1992 |
| Topstar International Education Services Limited | Professional & scientific | 2026 |
| Topsys Tiling Ltd | Construction | 2019 |
| Torib Offshore Safety and Medics Services Ltd | Wholesale & retail | 2014 |
| Torini NCL Limited | Administrative & support | 2012 |
| Toro IT Ltd | Information & communication | 1999 |
| Torpro Limited | Hospitality | 2005 |
| Torque Garage Ltd | Wholesale & retail | 2014 |
| Torque Tension Group Ltd | Wholesale & retail | 2024 |
| Torque Tension Systems Ltd | Wholesale & retail | 2026 |
| Torro Cases Ltd | Extraterritorial | 2014 |
| Torrrents Limited | Real estate | 2023 |
| Torsten TCG Accessories Ltd | Wholesale & retail | 2025 |
| Torver Property Ltd | Construction | 2026 |
| TOS Electrical Ltd | Construction | 2020 |
| TOS Installations Ltd | Construction | 2025 |
| TOS Productions Ltd | Construction | 2022 |
| Toshi Limited | Hospitality | 2012 |
| Toshi Property Management Ltd | Real estate | 2022 |
| Total Access Systems Limited | Manufacturing | 2022 |
| Total Electronic Security Limited | Construction | 2005 |
| Total Maths Tutoring Ltd | Education | 2020 |
| Total Pump Solutions Limited | Wholesale & retail | 2003 |
| Total Reclaim Limited | Other services | 2009 |
| Total Renewable Management Ltd | Manufacturing | 2013 |