| TOM Hartley Limited | Wholesale & retail | 1981 |
| TOM O'Brien Ltd | Arts & recreation | 2021 |
| Tomorrows Gadgets Limited | Wholesale & retail | 2015 |
| Tomtheelectrician Ltd | Construction | 2025 |
| Tony Torossian Electrical Contractors Limited | Construction | 2011 |
| Tool Talk Limited | Professional & scientific | 2024 |
| Toons Carpet and Furniture Centre Limited | Wholesale & retail | 1973 |
| Top Floor Custom Products Ltd | Professional & scientific | 2026 |
| Top Gear Tyre and Exhaust Centre Ltd | Manufacturing | 2009 |
| Top Sounds Ltd | Manufacturing | 2004 |
| Top Tier Physiotherapy Ltd | Health & social care | 2019 |
| TOPCO1 Ltd | Construction | 2020 |
| Torque Operations Ltd | Professional & scientific | 2025 |
| Torstone Holdings Limited | Professional & scientific | 2016 |
| Torstone Properties Limited | Real estate | 2020 |
| Tosca Supply Chain Solutions UK Ltd | Administrative & support | 2000 |
| Total Liquid Solutions Ltd | Manufacturing | 2017 |
| TPN Contingency Fund Limited | Other services | 2003 |
| TPS Process Limited | Professional & scientific | 2022 |
| TQS Solutions Limited | Construction | 2026 |
| TR Tech Services Ltd | Professional & scientific | 2014 |
| Traceacchip Ltd | Professional & scientific | 2023 |
| Trade Brand Ltd | Administrative & support | 2023 |
| Train 2 Excel Limited | Administrative & support | 2004 |
| Train Clean Limited | Extraterritorial | 2014 |
| Train Safety Limited | Extraterritorial | 2014 |
| Training Beat Ltd | Education | 2021 |
| Transform PMO Ltd | Professional & scientific | 2024 |
| Tread Safe Tyre Centre Limited | Wholesale & retail | 2020 |
| Trecarn Engineering Limited | Manufacturing | 1978 |
| Tree & Garden Services Hartshorne Ltd | Administrative & support | 2018 |
| Treow Flooring Limited | Construction | 2022 |
| Tres Cycles Limited | Manufacturing | 2006 |
| Trica Property Group Limited | Real estate | 2026 |
| Trident Powersports Limited | Manufacturing | 2011 |
| Trim Refurb Services Limited | Wholesale & retail | 1997 |
| Trio Insight Ltd | Information & communication | 2021 |
| Trio Leasing Ltd | Wholesale & retail | 2021 |
| Trio Partnerships Ltd | Financial services | 2021 |
| Triumph Bicycles Limited | Other services | 2017 |
| Triumph Bikes Limited | Other services | 2017 |
| Triumph Cycle Co. Limited | Other services | 2017 |
| Triumph Cycles Limited | Other services | 2017 |
| Triumph Designs Limited | Manufacturing | 1983 |
| Triumph E-Bikes Limited | Other services | 2017 |
| Triumph Motorcycles (Coventry) Limited | Professional & scientific | 1989 |
| Triumph Motorcycles (Overseas) Limited | Professional & scientific | 1990 |
| Triumph Motorcycles Limited | Manufacturing | 1983 |
| Triumph Parts & Accessories Limited | Professional & scientific | 1995 |
| TRL Property Investments Ltd | Real estate | 2026 |
| Trowel & Tenon Ltd | Construction | 2018 |
| Truck Driver Hire UK Ltd | Transport & logistics | 2023 |
| Truck Maintenance Ltd | Wholesale & retail | 2023 |
| Trufit Ltd | Arts & recreation | 2024 |
| Trustrent Holdings Ltd | Financial services | 2026 |
| Trustrent Residences Ltd | Hospitality | 2026 |
| TSC Project Consultant Ltd | Professional & scientific | 2025 |
| TSP Car Park Management Limited | Administrative & support | 2013 |
| TT Roofing Ltd | Construction | 2019 |
| TTM Maintenance Limited | Wholesale & retail | 2025 |
| Tunedkeys Ltd | Wholesale & retail | 2026 |
| Tunnel Vision Studios Limited | Arts & recreation | 2016 |
| TUR Transport Service Ltd | Transport & logistics | 2024 |
| Turfdry Limited | Construction | 1995 |
| Turner Redstone Ltd | Professional & scientific | 2025 |
| TUS Holdings Limited | Professional & scientific | 2017 |
| TWS Carpentry Limited | Construction | 2023 |
| Twyning Green Management Company Limited | Households | 2017 |
| Tyson Engineering Enterprises Ltd | Manufacturing | 2001 |
| TZO Trans Ltd | Transport & logistics | 2019 |
| UK Brandwear Ltd | Wholesale & retail | 2020 |
| UK Cyber Security Group Ltd | Information & communication | 2022 |
| UK Environment Fund | Professional & scientific | 1999 |
| UK Framing Supplies Ltd | Wholesale & retail | 2009 |
| UK Office Install Ltd | Construction | 2019 |
| UK Premier Supplies Ltd | Wholesale & retail | 2024 |
| UK Tools Direct Limited | Wholesale & retail | 2007 |
| Ultimate FM Ltd | Extraterritorial | 2015 |
| Ultracarbon Ltd | Professional & scientific | 2023 |
| Ultraviolet Software Ltd | Professional & scientific | 2024 |
| Umbrella Education and Training Ltd | Education | 2024 |
| Union Road Store Ltd | Construction | 2019 |
| Uniq Tech Ltd | Wholesale & retail | 2012 |
| Unique Finishes - Plastering Ltd | Construction | 2024 |
| Unique Property Construction Ltd | Construction | 2023 |
| Unique Van Linings (Yorkshire) Limited | Wholesale & retail | 2014 |
| Untold Horizons Limited | Transport & logistics | 2016 |
| Unwin Hydraulic Engineering Limited | Manufacturing | 1979 |
| Uplift (ARP) Limited | Households | 2025 |
| UPM Trade Limited | Wholesale & retail | 2015 |
| Upv-C Windows, Doors & Conservatories Ltd | Construction | 2003 |
| Upward AV Ltd | Administrative & support | 2026 |
| Urban Matrix (Sycamore) Limited | Real estate | 2011 |
| Ursbrand Ltd | Transport & logistics | 2026 |
| Urug Group Ltd | Financial services | 2024 |
| UVL Van Lining Yorkshire Limited | Manufacturing | 2017 |
| V-Eden Ltd | Health & social care | 2023 |
| Valmm Ltd | Health & social care | 2022 |
| Vanguard Medical Europe Limited | Manufacturing | 2024 |
| Vanguard Principal Limited | Professional & scientific | 2023 |