| Thornbury Park(Block C)Management Company Limited | Households | 1985 |
| Thornbury Park(Blocks a & B)Management Company Limited | Households | 1985 |
| Three Eagles Ltd | Construction | 2017 |
| Three M Sisters Ltd | Hospitality | 2020 |
| Three Peas Limited | Real estate | 2013 |
| Three Pharaohs Real Estate Ltd | Real estate | 2022 |
| Three US (UK) Ltd | Wholesale & retail | 2010 |
| Threefourteen Polymers Ltd | Wholesale & retail | 2013 |
| THRIV3 Consulting Ltd | Professional & scientific | 2024 |
| Tijay Investors Ltd | Real estate | 2023 |
| Tile in Progress Ltd | Construction | 2022 |
| TIM Delivery Ltd | Transport & logistics | 2023 |
| Timle Limited | Wholesale & retail | 2025 |
| Timsons Holdings Limited | Financial services | 2023 |
| Timsons Properties Limited | Real estate | 2023 |
| TJM Freehold Ltd | Real estate | 2025 |
| Tjmed Ltd | Professional & scientific | 2025 |
| TKL Development Ltd | Real estate | 2017 |
| TM Clinic LLP | | 2014 |
| TMD Air Conditioning Ltd | Construction | 2026 |
| TMG Waste Clearance Ltd | Water & waste | 2026 |
| TMM Design & Project Management Services Limited | Construction | 2020 |
| TN Project Management Limited | Professional & scientific | 2006 |
| Tntpremierproperties Limited | Real estate | 2020 |
| Toby Installation Building Limited | Construction | 2025 |
| Toby Mills Electrical Limited | Construction | 2012 |
| TOD Properties Ltd | Real estate | 2013 |
| Tokyo Apex Ltd | Wholesale & retail | 2020 |
| Tolwanaaje Support Group Ltd | Health & social care | 2022 |
| TOM & Poolee (UK) Limited | Manufacturing | 2004 |
| Tomar Ltd | Real estate | 2019 |
| Tommy Green Landscaping Ltd | Professional & scientific | 2026 |
| Tommy's Studio Limited | Professional & scientific | 2026 |
| Tomo VJ Ltd | Wholesale & retail | 2014 |
| Tooled UP Foundation CIC | Education | 2024 |
| Top Achievement Ltd | Education | 2020 |
| Top HAT DRY Cleaners Ltd | Other services | 2025 |
| Top Medical Clinic Limited | Health & social care | 2021 |
| Top Style Barber Limited | Other services | 2020 |
| Top Tier Logistics Ltd | Transport & logistics | 2021 |
| Topfloorlabel Ltd | Wholesale & retail | 2023 |
| Torrington Gardens Management Company Limited | Households | 2019 |
| Toto Courier Ltd | Transport & logistics | 2025 |
| TP Constructors Ltd | Construction | 2023 |
| Traffdesign Limited | Professional & scientific | 2016 |
| Traffickingads Limited | Information & communication | 2012 |
| Trana Services Limited | Professional & scientific | 2017 |
| Transflex Logistics Solutions Ltd | Transport & logistics | 2020 |
| Transformity Limited | Information & communication | 2003 |
| Transistor Films Limited | Information & communication | 2014 |
| Travel Compare Ltd. | Administrative & support | 2010 |
| Travel England Tours Ltd | Administrative & support | 2018 |
| Trcw Ltd | Professional & scientific | 2025 |
| Treadldn Ltd | Wholesale & retail | 2020 |
| Treats World Ltd | Wholesale & retail | 2019 |
| Trendyvibenest Limited | Wholesale & retail | 2025 |
| Trentcrown Limited | Financial services | 2004 |
| TRG Trade Solutions Ltd | Information & communication | 2012 |
| Trident Commercial Finance Ltd | Financial services | 2019 |
| Trident Finance Ltd | Professional & scientific | 2025 |
| Trident Mgmt Ltd | Professional & scientific | 2024 |
| Trilab Ltd | Administrative & support | 2021 |
| Trinity Traders Ltd | Wholesale & retail | 2024 |
| Tripathi Holdings Limited | Real estate | 2025 |
| Tripping OUT Electrics Ltd | Construction | 2022 |
| Truckerpro Ltd | Transport & logistics | 2023 |
| True North Productions Limited | Information & communication | 2002 |
| Truelity Limited | Energy | 2024 |
| Truflame Hospitality Limited | Hospitality | 2025 |
| Trusted Transfers Ltd. | Transport & logistics | 2016 |
| TS Global Ltd | Wholesale & retail | 2021 |
| TSC (Legal) Consulting Limited | Professional & scientific | 2018 |
| Tserdnahub Ltd | Information & communication | 2025 |
| TT Inspired Consultancy Limited | Information & communication | 2022 |
| Turkmen Catering Ltd | Hospitality | 2021 |
| Turret & Gate Ltd | Real estate | 2020 |
| TW12PUB Limited | Hospitality | 2022 |
| TW7 GAP Limited | Information & communication | 2014 |
| TW7 Supermarket Ltd | Wholesale & retail | 2020 |
| TW7BEV Limited | Wholesale & retail | 2023 |
| Tweety Clean Ltd | Administrative & support | 2020 |
| Twickenham Furniture Ltd | Construction | 2020 |
| Two Paddles Ltd | Information & communication | 2016 |
| Two Plus Voices Limited | Information & communication | 2021 |
| Twynz Aerospace Limited | Professional & scientific | 2024 |
| Tymac Limited | Information & communication | 2020 |
| Typhoon Associates Limited | Information & communication | 2013 |
| Tyss Group Ltd | Hospitality | 2025 |
| UA Consulting Services Ltd | Information & communication | 2022 |
| UA Property Management Limited | Real estate | 2024 |
| UB68 Kitchen Limited | Hospitality | 2025 |
| Ubhi & Jassal Holdings Ltd | Real estate | 2026 |
| UK Box Maker Limited | Wholesale & retail | 2026 |
| UK Compliance Services Limited | Professional & scientific | 2020 |
| UK DH Group Ltd | Water & waste | 2025 |
| UK Homemart Ltd | Wholesale & retail | 2018 |
| UK Immigration Advisors Ltd | Professional & scientific | 2024 |
| UKC Investment Ltd | Real estate | 2016 |
| Umet Group Ltd | Construction | 2018 |
| Uniproedu Ltd | Education | 2024 |