| Thomas Window Repairs Limited | Construction | 2017 |
| Thorpe 24 Ltd | Hospitality | 2025 |
| Thracians'Truck Limited | Transport & logistics | 2019 |
| Threaders Apartments Limited | Households | 2016 |
| Thream Ltd | Real estate | 2022 |
| Three Little Birds Construction Ltd | Real estate | 2016 |
| Three Tall Tree's Limited | Professional & scientific | 2025 |
| Threshers Convenience Ltd | Wholesale & retail | 2016 |
| Thrillscape UK Ltd | Manufacturing | 2014 |
| Thrive Communications Ltd. | Professional & scientific | 2014 |
| Thrive Dyslexia Assessments and Adhd Coaching Ltd | Education | 2023 |
| Thrive Healthcare Services Ltd | Health & social care | 2026 |
| Thryva Labs Ltd | Professional & scientific | 2025 |
| Thryve & Co Limited | Wholesale & retail | 2024 |
| Thurlow Park Management Limited | Real estate | 1987 |
| Tianmao Ltd | Wholesale & retail | 2024 |
| Tide Villa Ltd | Real estate | 2024 |
| Tidywhite Cleaning Services Ltd | Administrative & support | 2023 |
| Tight Fit Flooring Ltd. | Wholesale & retail | 2002 |
| Tiktok Hair Ltd | Other services | 2021 |
| Tile Roofing Limited | Construction | 2025 |
| Tileex Limited | Construction | 2011 |
| Tima London CIC | Education | 2020 |
| Timberley Court Limited | Real estate | 2021 |
| Time Instruments Limited | Administrative & support | 1955 |
| Time Power Services Limited | Professional & scientific | 2014 |
| Time to Refurbish Limited | Construction | 2009 |
| Timed Couriers Ltd | Administrative & support | 2025 |
| Timegolden Ltd | Administrative & support | 2009 |
| Timeless & Eternal CIC | Wholesale & retail | 2022 |
| Times Apartments (London) RTM Company Limited | Real estate | 2025 |
| Timians Way Management Company Limited | Households | 2019 |
| Timsbury Holdings Limited | Real estate | 2015 |
| Tina Court Residents Association Limited | Real estate | 1993 |
| Ting Beauty Limited | Other services | 2020 |
| Tiny Dinosaur Productions Limited | Information & communication | 2012 |
| Tipp IT Waste Clearance Ltd | Water & waste | 2019 |
| Tira Entertainment Limited | Arts & recreation | 2025 |
| Titan 23 Limited | Professional & scientific | 2024 |
| Titans Studio Ltd | Information & communication | 2025 |
| Tj&Qs Ltd | Real estate | 2019 |
| Tjag Consulting Ltd | Professional & scientific | 2026 |
| TJE Interior & Exteriors Ltd | Manufacturing | 2026 |
| TJW Electrical Services Ltd | Construction | 2024 |
| TK Nurwin Limited | Transport & logistics | 2016 |
| TK PEN Limited | Real estate | 2025 |
| TKF Consulting Limited | Professional & scientific | 2024 |
| TKO Solutions Ltd | Information & communication | 2026 |
| TL Electronics Limited | Wholesale & retail | 2016 |
| Tlismet Ltd | Hospitality | 2025 |
| TLM Construction Ltd | Construction | 2023 |
| TLM Property Ltd | Real estate | 2023 |
| Tmdm Services Ltd | Real estate | 2025 |
| TMG Trading Limited | Construction | 2014 |
| TMJ Business Enterprise Limited | Transport & logistics | 2011 |
| TMK Electrics Limited | Energy | 2003 |
| Tmmersive Sound Ltd | Information & communication | 2025 |
| Tmsg Limited | Health & social care | 2017 |
| Tmzzs Ltd | Real estate | 2021 |
| TN Global Co Ltd | Wholesale & retail | 2020 |
| TNS Property Maintenance Ltd | Construction | 2026 |
| TNT Research Ltd | Information & communication | 2025 |
| TOB Resources Limited | Extraterritorial | 2011 |
| Tobias AI Ltd | Information & communication | 2025 |
| Tobias-Davis Limited | Manufacturing | 2003 |
| Toby Liberman Furniture Limited | Manufacturing | 2012 |
| Toby Peacock Limited | Professional & scientific | 2024 |
| Toderawns Ltd | Construction | 2025 |
| Tofu Estates Limited | Real estate | 2023 |
| Together Rising CIC | Health & social care | 2026 |
| Tokei Martial Arts Club Limited | Arts & recreation | 2007 |
| Tokem Systems Associates Limited | Information & communication | 2006 |
| Toland Ltd | Professional & scientific | 2015 |
| Tolann Holdings Limited | Information & communication | 2020 |
| Tollgate Lodge Management Company Limited | Households | 2008 |
| TOM Hennigan Limited | Health & social care | 2022 |
| TOM Loch Consultancy Ltd | Professional & scientific | 2025 |
| Tomoro Limited | Professional & scientific | 2018 |
| Tongdam Thai Restaurants Limited | Hospitality | 2003 |
| Tonvic Investments Ltd | Real estate | 2022 |
| Tony Decorating Services Limited | Administrative & support | 2007 |
| Tony Evans Consulting Limited | Professional & scientific | 2009 |
| Tony Trans Ltd | Transport & logistics | 2024 |
| Tony Viney Limited | Administrative & support | 1964 |
| Tony's Construction Ltd | Construction | 2022 |
| Tonys Fried Chicken Limited | Hospitality | 2024 |
| Toogood & Smith Ltd | Real estate | 2018 |
| Tool Britannia Limited | Wholesale & retail | 2012 |
| Tool Locker Limited | Information & communication | 2025 |
| Toomey Project Management Consultants Limited | Professional & scientific | 2007 |
| Top Fryer Limited | Hospitality | 2017 |
| Top Jobs Group Ltd | Administrative & support | 2020 |
| Top Markes Ltd | Administrative & support | 2020 |
| Top PAD Ltd. | Real estate | 2004 |
| Top Tier Refurbs & Maintenance Ltd | Construction | 2026 |
| Top UP Truck Bromley Ltd | Wholesale & retail | 2026 |
| Top Yellow Ltd | Professional & scientific | 2025 |
| Toppack Packaging Solutions Ltd | Extraterritorial | 2014 |
| Topside Marine Ltd | Extraterritorial | 2023 |
| Torcraig Limited | Extraterritorial | 2001 |