| Thinkux Ltd | Professional & scientific | 2013 |
| Thiru Cluster Limited | Wholesale & retail | 2013 |
| THJ Consultancy Ltd | Professional & scientific | 2012 |
| Three Doons Groundworks Ltd | Construction | 2022 |
| Three Dots Group Ltd | Information & communication | 2015 |
| Thugs London C.I.C. | Health & social care | 2019 |
| Thulashi Ltd | Real estate | 2020 |
| Thummar Renovation Limited | Construction | 2026 |
| Tiand Global Nest Ltd | Real estate | 2020 |
| Tiand Trading Limited | Wholesale & retail | 2016 |
| Tiara Lohani Limited | Hospitality | 2022 |
| Tickly Toes Day Nursery and Montessori Limited | Health & social care | 2023 |
| Ties Building Services Ltd | Construction | 2024 |
| Tiflii Ltd | Wholesale & retail | 2023 |
| Tigress Ltd | Real estate | 2024 |
| Tint Theory Ltd | Construction | 2020 |
| Tirat London Ltd | Wholesale & retail | 2025 |
| TJ Prime Ltd | Wholesale & retail | 2023 |
| Tkms Wine Ltd | Wholesale & retail | 2026 |
| TKS Transport Ltd | Transport & logistics | 2022 |
| TLR Private Ltd | Wholesale & retail | 2022 |
| TM Team Ltd | Construction | 2024 |
| TMK Spedition Ltd | Transport & logistics | 2023 |
| TMZ Payroll Services Ltd | Professional & scientific | 2025 |
| Tnri Ltd | Information & communication | 2026 |
| TO the Point Solutions Ltd | Administrative & support | 2023 |
| Toarka Ltd | Construction | 2025 |
| Tobyas Services Limited | Transport & logistics | 2025 |
| Todos Trade Limited | Other services | 2023 |
| TOK Mark Traders Limited | Wholesale & retail | 2018 |
| Told Ltd | Construction | 2026 |
| Toolmstr Ltd | Construction | 2023 |
| Top Class Painting & Decorating Ltd | Construction | 2016 |
| Top MEN Cleaning Service Ltd | Administrative & support | 2024 |
| Top MEN Removals Ltd | Transport & logistics | 2021 |
| Top Quality Construction Limited | Construction | 2014 |
| Toppet Company Limited | Manufacturing | 2022 |
| Topps FIX Ltd | Wholesale & retail | 2014 |
| Tornado Digital Limited | Wholesale & retail | 2008 |
| Torquay Property Ltd | Real estate | 2022 |
| Tosk Group Ltd | Administrative & support | 2026 |
| Total IT Consultants Ltd | Information & communication | 2026 |
| Tower AGE Construction Ltd | Construction | 2022 |
| TR Eco Solutions Limited | Construction | 2012 |
| Trade Genius Limited | Wholesale & retail | 2017 |
| Tradeseeker Limited | Financial services | 2024 |
| Trained by SAJ Limited | Arts & recreation | 2020 |
| Trans and Traders Ltd | Transport & logistics | 2026 |
| Transport Counsellors Ltd | Professional & scientific | 2020 |
| Travelina Ltd | Administrative & support | 2025 |
| TRD Property Ltd | Real estate | 2014 |
| TRD Residential Ltd | Real estate | 2016 |
| Trendsetter Lifestyle Limited | Professional & scientific | 2025 |
| Trendsetter London Ltd | Manufacturing | 2017 |
| Trendsetting Accessories Ltd | Wholesale & retail | 2022 |
| Trendsite Property Management Limited | Households | 1991 |
| Tri-Activity Camps Limited | Health & social care | 2022 |
| Tri-Axis Engineering Ltd | Manufacturing | 2026 |
| Trinders Courier & Removal Services Ltd. | Transport & logistics | 2012 |
| Trinketz Ltd | Wholesale & retail | 2021 |
| Trinqo Limited | Other services | 2019 |
| TRK Maria Ltd | Transport & logistics | 2023 |
| TRT Consultants Ltd | Construction | 2024 |
| True Heritage Ltd | Wholesale & retail | 2025 |
| True Value Builders Limited | Other services | 2017 |
| Trust PC Expert Ltd | Information & communication | 2022 |
| Trustbill Limited | Transport & logistics | 2018 |
| Trutek Europe Ltd | Wholesale & retail | 2009 |
| Tsvetkov Ltd | Other services | 2011 |
| TT Accountants & Financial Services Ltd | Professional & scientific | 2023 |
| TT Consultancy Services Ltd | Professional & scientific | 2018 |
| Tuaahaa S Trader Ltd | Wholesale & retail | 2024 |
| Tucker's Craft Spirits Limited | Wholesale & retail | 2021 |
| Tundii Limited | Wholesale & retail | 2021 |
| Turbo TCG Ltd | Wholesale & retail | 2025 |
| Twinkle Totz Day Nursery Limited | Health & social care | 2008 |
| TY Parenting Assessment Services Limited | Health & social care | 2018 |
| Tyler & Jo’S Bees Limited | Agriculture & fishing | 2024 |
| Tyme Waterfront Ltd | Hospitality | 2016 |
| U&P Crystal Cleaning Services Ltd | Administrative & support | 2018 |
| Ugly Head Ltd | Information & communication | 2019 |
| UK & Commonwealth International Academy Ltd | Administrative & support | 2024 |
| UK Build Pro Ltd | Construction | 2016 |
| UK Construction Ltd Limited | Real estate | 2015 |
| UK DEA Limited | Real estate | 2025 |
| UK Executive Chauffeurs Ltd | Transport & logistics | 2024 |
| UK Fone Retailer Limited | Wholesale & retail | 2018 |
| UK London Steel Solutions Ltd | Manufacturing | 2019 |
| UK Paramount Properties Limited | Real estate | 2022 |
| UK Party in Style Ltd | Hospitality | 2010 |
| UK Philippines Asia Atlantic (Ukpaa) Limited | Wholesale & retail | 2025 |
| UK Premier Fuel Ltd | Wholesale & retail | 2013 |
| UK Sparks Ltd | Construction | 2018 |
| Ukay Accounting Services Ltd | Professional & scientific | 2023 |
| Ultimate Consultancy & Advisory Network Limited | Education | 2014 |
| ULTRA-BEAM350 Ltd | Manufacturing | 2020 |
| Ulzii Limited | Hospitality | 2024 |
| Umiya E-Commerce Ltd | Wholesale & retail | 2026 |
| Umunede Progressive Union United Kingdom (Upu-Uk) Limited | Other services | 2015 |
| Uncovered Beauty Ltd | Manufacturing | 2018 |