| Thrive M&E Ltd | Construction | 2020 |
| Thrive Sports Management Limited | Arts & recreation | 2020 |
| Thriveharrow Community CIC | Education | 2026 |
| Thriver Ltd | Financial services | 2022 |
| Thriving Futures 2100 C.I.C. | Education | 2024 |
| Thubhu Ltd | Real estate | 2026 |
| Thural DAD Productions Ltd | Information & communication | 2020 |
| Thuraya Lifestyle UK Ltd | Manufacturing | 2022 |
| Thurlby Close Freehold Company Limited | Households | 2013 |
| Thurlby Close Residents (Kenton) Limited | Households | 2014 |
| Thursday the New Friday Limited | Information & communication | 2023 |
| Thyme Keepers Ltd | Other services | 2017 |
| Thyrve Ltd | Real estate | 2025 |
| TI Decor Ltd | Construction | 2022 |
| TI Roche Limited | Administrative & support | 2008 |
| Tiad Consultancy Ltd | Information & communication | 2012 |
| Tiakab Limited | Real estate | 2023 |
| Tiana Fair Trade Organics Limited | Manufacturing | 2006 |
| Tiana Limited | Extraterritorial | 2011 |
| Tiana Properties Ltd | Real estate | 2020 |
| Tiberius Marian Ltd | Construction | 2019 |
| Tiberius Trade Ltd | Construction | 2019 |
| Tibet Foundation | Education | 2020 |
| Tickets to Everywhere UK Ltd | Administrative & support | 2014 |
| Tickle Entertainment Limited | Information & communication | 2022 |
| Tickle Productions 1 Limited | Information & communication | 2022 |
| Tickster Limited | Information & communication | 2023 |
| Tidal Investments Limited | Real estate | 2011 |
| Tiel Ltd | Real estate | 2018 |
| Tiera Ltd | Real estate | 2021 |
| TIERA2 Ltd | Real estate | 2022 |
| Tierra Designs Limited | Administrative & support | 2002 |
| Tiexpress Limited | Transport & logistics | 2019 |
| Tiffin to Go Limited | Hospitality | 2025 |
| Tiger Blue Events T/A Brios London Ltd | Hospitality | 2018 |
| Tiger Dragon London Ltd | Hospitality | 2025 |
| Tiger Investments 1 Limited | Real estate | 2018 |
| Tiger Investments 2 Limited | Real estate | 2018 |
| Tiger Investments 3 Limited | Real estate | 2018 |
| Tiger Investments 4 Limited | Real estate | 2019 |
| Tiger Investments 5 Limited | Real estate | 2019 |
| Tiger Investments 6 Limited | Real estate | 2020 |
| Tiger Investments 7 Limited | Real estate | 2020 |
| Tiger Investments 8 Limited | Real estate | 2020 |
| Tiger Investments 9 Limited | Real estate | 2019 |
| Tiger of Sweden UK Ltd | Wholesale & retail | 2018 |
| Tiger Thukash Ltd | Wholesale & retail | 2022 |
| Tiger.I&C Ltd | Wholesale & retail | 2018 |
| Tigerland Limited | Information & communication | 2017 |
| Tigers Property Limited | Real estate | 2022 |
| Tigrisse Limited | Real estate | 2014 |
| Tihan Limited | Construction | 2018 |
| Tiien Group Ltd | Hospitality | 2015 |
| Tiien Holdings Limited | Financial services | 2019 |
| Tiien Limited | Hospitality | 2012 |
| Tiien Southbourne Limited | Hospitality | 2019 |
| Tiksiy Property Group Limited | Real estate | 2026 |
| Tilak Foods Limited | Wholesale & retail | 1983 |
| Tilak Hina Dental Limited | Health & social care | 2019 |
| Tilak News Ltd | Wholesale & retail | 2023 |
| Tile King Limited | Construction | 2010 |
| Tile Trendz Ltd | Wholesale & retail | 2024 |
| Tileday Limited | Real estate | 1998 |
| Tiles Store Ltd | Wholesale & retail | 2019 |
| Tilfinch Limited | Construction | 1975 |
| Tilley & Barrett Limited | Construction | 1951 |
| Tillingbourne Brewery Ltd | Manufacturing | 2011 |
| Tills Consultancy Limited | Professional & scientific | 2023 |
| TIM Higham Ltd | Real estate | 2011 |
| TIM Lane Consulting Ltd | Professional & scientific | 2022 |
| Timan Property Limited | Real estate | 2018 |
| Timber Lodge Studio Ltd | Manufacturing | 2021 |
| Timber World Ltd | Wholesale & retail | 2012 |
| Timberbox Carpentry and Construction Ltd | Manufacturing | 2022 |
| Timberwood UK Ltd | Wholesale & retail | 2015 |
| Timble Technologies Limited | Information & communication | 2024 |
| Time & Chance Limited | Manufacturing | 1998 |
| Time 2 Heal Therapy Service Limited | Other services | 2014 |
| Time Tarp Ltd | Other services | 2021 |
| Time to Graft Limited | Information & communication | 2016 |
| TIME2RELAX London Ltd | Other services | 2025 |
| TIME2RELAX UK Ltd | Health & social care | 2025 |
| Timebarn Limited | Real estate | 2005 |
| Timelaw Limited | Construction | 1987 |
| Timeless Residence Ltd | Real estate | 2023 |
| Timotheus Engineering Ltd | Construction | 2025 |
| Timothy Ridout Ltd | Arts & recreation | 2023 |
| Timt Ltd | Wholesale & retail | 2025 |
| Timval Ltd | Wholesale & retail | 2023 |
| Timvero Ltd | Information & communication | 2021 |
| TIN FU Limited | Wholesale & retail | 2003 |
| Tina Hygienist Limited | Health & social care | 2017 |
| Tindacol Limited | Wholesale & retail | 2004 |
| Tinies Childcare Berkshire Nurseries Ltd | Administrative & support | 2008 |
| Tinies Childcare Herts and Bucks Limited | Administrative & support | 2007 |
| Tinies UK Recruitment Ltd | Administrative & support | 2024 |
| Tinker Tigers Ltd | Education | 2022 |
| Tinkerbell Cleaners Ltd | Administrative & support | 2019 |
| Tinroof Ventures Limited | Real estate | 2020 |
| Tint (London) Limited | Professional & scientific | 2009 |