| Thesuitman&Co Ltd | Wholesale & retail | 2023 |
| Think Aqua Limited | Professional & scientific | 2005 |
| Think Repair Limited | Other services | 2018 |
| Thinkhat Software (UK) Limited | Information & communication | 2021 |
| Thirajam Limited | Wholesale & retail | 2014 |
| Third EYE Team Ltd | Professional & scientific | 2014 |
| Thirty SIX Films Ltd | Information & communication | 2026 |
| Thirty-Nine Highbury Hill (Freehold) Limited | Households | 2005 |
| Thivi Limited | Wholesale & retail | 2026 |
| Thiya Medical Services Ltd | Health & social care | 2022 |
| Thoracic Surgery Limited | Health & social care | 2010 |
| Thorndale Properties Limited | Households | 1981 |
| Thread Build Ltd | Construction | 2026 |
| Threadwell Management Limited | Households | 2014 |
| Three Brothers Roadworks Ltd | Construction | 2026 |
| Three Childern Limited | Other services | 2013 |
| Three Feathers Tours Limited | Administrative & support | 2024 |
| Three Principles Online CIC | Education | 2022 |
| Three Swords Music Ltd | Arts & recreation | 2025 |
| THREE5ONE Music Limited | Information & communication | 2024 |
| Threewaves Limited | Information & communication | 2015 |
| Thrive at Home Care Limited | Health & social care | 2024 |
| Thunder Motors Ltd | Wholesale & retail | 2024 |
| Thunderbolt Limited | Information & communication | 1994 |
| TI & TI Limited | Households | 2023 |
| Tiata Fahodzi Ltd | Arts & recreation | 1997 |
| TIB Rail Limited | Construction | 2019 |
| Tiberonix Ltd | Wholesale & retail | 2024 |
| Tick the Box Ltd | Water & waste | 2025 |
| Ticl Media Limited | Information & communication | 2011 |
| Tierney IT Solutions Ltd | Information & communication | 2017 |
| Tierra Consultancy Ltd | Professional & scientific | 2022 |
| Tierra Properties Ltd | Real estate | 2022 |
| Tigris London Limited | Wholesale & retail | 2012 |
| Tikkipharma Ltd | Health & social care | 2024 |
| Tilak Ltd | Construction | 2025 |
| Tilbrok Limited | Professional & scientific | 2025 |
| Tilehouse Properties (Newport Pagnell) Limited | Real estate | 2025 |
| Tillky Limited | Professional & scientific | 2012 |
| Time TEC Ltd | Information & communication | 2014 |
| Time Valley Group Ltd | Information & communication | 2025 |
| Timeless (London) Ltd | Information & communication | 2013 |
| Timeless Treasures & Co. Ltd | Wholesale & retail | 2025 |
| Timisoreana Limited | Hospitality | 2018 |
| Timofte Building Ltd | Construction | 2019 |
| TIN Construct Ltd | Construction | 2023 |
| Tina's Hair & Products Ltd | Hospitality | 2010 |
| Tindermark Limited | Professional & scientific | 2014 |
| Tinibox Ltd | Wholesale & retail | 2021 |
| Tinta Madre Limited | Professional & scientific | 2023 |
| Tip-Top Strides (Whitechapel) Limited | | 1979 |
| Tipster Hub Ltd | Professional & scientific | 2023 |
| TIS Ventures UK Limited | Information & communication | 2017 |
| Tisha Angles Ltd | Real estate | 2018 |
| Titan Cars Ltd | Wholesale & retail | 2024 |
| Titan Guard Services Ltd | Administrative & support | 2025 |
| Titanium Investment Management Limited | Professional & scientific | 2010 |
| Tiwan Limited | Real estate | 2021 |
| TJ Estate Holdings Limited | Real estate | 2022 |
| TJB Landlords Ltd | Real estate | 2019 |
| TJP365 Ltd | Information & communication | 2024 |
| TJW Famco 1 Limited | Professional & scientific | 2021 |
| TJW Famco 2 Limited | Professional & scientific | 2021 |
| TJW Famco 3 Limited | Professional & scientific | 2021 |
| TK Investments (London) Limited | Real estate | 2022 |
| TKS Crafts Ltd | Wholesale & retail | 2025 |
| Tkshopplus Ltd | Wholesale & retail | 2025 |
| TL Catering (London) Ltd | Hospitality | 2017 |
| TLC Food Ltd | Hospitality | 2022 |
| Tlguk Health Ltd | Health & social care | 2018 |
| Tlguk Ltd | Health & social care | 2013 |
| TLR London Ltd | Wholesale & retail | 2016 |
| TLV Falafel Limited | Hospitality | 2023 |
| TM Piping Design Limited | Professional & scientific | 2018 |
| TMC Management Limited | Real estate | 2014 |
| TMJ Beauty World Ltd | Wholesale & retail | 2010 |
| TMM Estates Ltd | Real estate | 2026 |
| TMS Construction Ltd | Construction | 2025 |
| TMT Audio Limited | Information & communication | 2024 |
| TMV Group Limited | Information & communication | 2021 |
| TNG Holdings (UK) Ltd | Households | 2018 |
| TNV Construction Limited | Construction | 2001 |
| TNV Investments Limited | Real estate | 2012 |
| TNV Properties Ltd | Real estate | 2017 |
| Tobiasink Ltd | Information & communication | 2016 |
| Toby’S Properties Ltd | Real estate | 2022 |
| Today Exchange Ltd | Financial services | 2026 |
| Todorov Heating & Plumbing Limited | Energy | 2018 |
| Tokatara Limited | Professional & scientific | 2022 |
| Tokzy Ventures Limited | Health & social care | 2014 |
| Tolfor Limited | Professional & scientific | 2025 |
| Tolo Ltd | Extraterritorial | 2016 |
| Tolpuddle Dental Practice Ltd | Health & social care | 2007 |
| Tolwin Limited | Professional & scientific | 2024 |
| TOM Stone Music Limited | Information & communication | 2012 |
| TOM Wholesale Ltd | Wholesale & retail | 2026 |
| Toma Landscaping Ltd | Professional & scientific | 2025 |
| Tomarebs Limited | Professional & scientific | 2013 |
| Tommy’S Building Solutions Limited | Construction | 2021 |
| Tongo Motors Limited | Wholesale & retail | 2024 |