| Tillingbourne (ST Albans) Limited | Construction | 2017 |
| Tilwin Consulting Limited | Professional & scientific | 2023 |
| TIM Tatham Consulting Limited | Education | 2003 |
| Timber & Stone Construction Ltd | Construction | 2025 |
| Timber Dryers Ltd | Wholesale & retail | 2018 |
| Time Critical International Limited | Information & communication | 2002 |
| Time for Tea C.I.C. | Health & social care | 2026 |
| Time for Tea Companions Ltd | Health & social care | 2024 |
| Time Pe@Ce Advisors Limited | Information & communication | 2020 |
| Time Watch Repair Ltd | Wholesale & retail | 2020 |
| TIME4CORE LLP | | 2022 |
| Timnical Limited | Professional & scientific | 1994 |
| Timothy Groves Ltd | Administrative & support | 2022 |
| TIN Electrical Services Ltd | Manufacturing | 2026 |
| TIN TIN Enterprises Limited | Wholesale & retail | 2014 |
| Titan Industrial Limited | Real estate | 2023 |
| Titleworth Limited | Health & social care | 2025 |
| Tixserve Holdings Limited | Information & communication | 2025 |
| TJ Property Letting Ltd | Real estate | 2018 |
| TJC Business Solutions Limited | Professional & scientific | 2025 |
| TJL Productions Limited | Arts & recreation | 2014 |
| TK Garden Services Limited | Administrative & support | 2020 |
| Tkey Consulting Limited | Professional & scientific | 2014 |
| TLC the Learning Centre (Bromley) Ltd | Education | 2012 |
| Tlgg Private Dining Limited | Hospitality | 2020 |
| TLM Consulting Ltd | Professional & scientific | 2026 |
| TLP Plumbing & Heating Limited | Construction | 2016 |
| TLT (Camborne Mews) Limited | Real estate | 2025 |
| TLT Construction (Woodfield Gardens) Limited | Construction | 2024 |
| TLT Construction Limited | Construction | 2023 |
| TM Bespoke Solutions Ltd | Construction | 2018 |
| TM Consultants Limited | Professional & scientific | 1984 |
| Tmbd Ventures Limited | Construction | 2017 |
| TMC Engineering Ltd | Professional & scientific | 2024 |
| TMM Commercial, Development & Overseas Limited | Financial services | 2015 |
| TMZ Homes Limited | Real estate | 2023 |
| TNL Property Investment & Consultancy Limited | Real estate | 2024 |
| TNS Beauty Ltd | Wholesale & retail | 2026 |
| Today's PA Limited | Education | 2019 |
| Today's Training Courses Ltd | Professional & scientific | 2005 |
| Tofino Sky Limited | Real estate | 2014 |
| Together in Safety | Professional & scientific | 2021 |
| Tokatide Limited | Financial services | 2019 |
| Token Tours Limited | Administrative & support | 2025 |
| Toku Properties Ltd | Real estate | 2021 |
| Tolulope Limited | Professional & scientific | 2023 |
| Tomstell Ltd | Construction | 2023 |
| Tonsley (Condor Park) Ltd | Extraterritorial | 2022 |
| Tonsley (Livingston NO.2) Ltd | Extraterritorial | 2014 |
| Tonsley (Livingston) Ltd | Extraterritorial | 2014 |
| Tonsley Consulting Ltd | Real estate | 2005 |
| Tonsley Holdings Ltd | Real estate | 2018 |
| Tonto Media Limited | Administrative & support | 2006 |
| Tony Halliwell Music (THM) Limited | Information & communication | 2026 |
| Tony Myatt Studio Limited | Arts & recreation | 2013 |
| Toorak Capital Partners (UK) Limited | Administrative & support | 2017 |
| Tootsies Private Day Nursery (Holdings) Limited | Professional & scientific | 2012 |
| Tootsies Private Day Nursery Ltd | Education | 2003 |
| Top Aces Europe Ltd | Public administration | 2023 |
| Top Brands Direct Limited | Wholesale & retail | 2012 |
| Top Fruit International Limited | Professional & scientific | 2022 |
| Top Line Fascias Ltd | Construction | 2023 |
| Top Office Personnel Limited | Manufacturing | 1988 |
| Top Table Caterers Ltd | Hospitality | 2019 |
| Topdollarmobile.Com Limited | Information & communication | 2009 |
| Tophat TCG Ltd | Wholesale & retail | 2024 |
| Topnexus Limited | Financial services | 2021 |
| Topnut 2022 Limited | Agriculture & fishing | 2023 |
| Tops Pizza Guildford Ltd | Hospitality | 2025 |
| Tormead Limited | Education | 1950 |
| Total Developments Southern Limited | Construction | 2009 |
| Total Integrated Construction Services Limited | Professional & scientific | 1989 |
| Total LOO Hire Limited | Administrative & support | 2025 |
| TOUR1004 Ltd | Arts & recreation | 2024 |
| TOURNESOL66 Limited | Extraterritorial | 2011 |
| Tower Machine Tools Limited | Wholesale & retail | 1976 |
| Tower Steel (Holdings) Limited | Professional & scientific | 1972 |
| Townextra Property Management Limited | Real estate | 1989 |
| Townsend-Coates Limited | Professional & scientific | 1961 |
| TP Industries Limited | Administrative & support | 2021 |
| TP Vision United Kingdom Ltd | Wholesale & retail | 2011 |
| TP16 Limited | Professional & scientific | 2012 |
| TP17 Limited | Real estate | 2019 |
| TPL Management Consultancy Limited | Professional & scientific | 1991 |
| Tpson Ltd | Administrative & support | 2022 |
| Trabon Consulting Limited | Professional & scientific | 2017 |
| Trackerdog Productions Ltd | Professional & scientific | 2024 |
| Tradepak UK Limited | Administrative & support | 2018 |
| Tradeprovider Limited | Wholesale & retail | 2020 |
| Trading Post Connections Limited | Professional & scientific | 1998 |
| Traffic Experiment Music Limited | Information & communication | 2008 |
| Trans-Caspian Trading S.A. | | 2004 |
| Trans-World Events Ltd | Administrative & support | 2023 |
| Transbuddy Ltd | Professional & scientific | 2024 |
| Transformers & Rectifiers (Holdings) Limited | Manufacturing | 2006 |
| Transfrm Limited | Information & communication | 2018 |
| Translloyd (Salford) Limited | Real estate | 2001 |
| Translloyd (Salford) Management Company NO.1 Limited | Real estate | 2003 |
| Translloyd (Salford) Management Company NO.2 Limited | Real estate | 2003 |
| Translloyd Developments Ltd. | Real estate | 1998 |