| Toshua Ltd | Other services | 2025 |
| Total Build Services Ltd | Construction | 2024 |
| Total Care Ltd | Health & social care | 2024 |
| Total Cellar Services Limited | Hospitality | 2019 |
| Total Driveway Supplies Limited | Administrative & support | 2006 |
| Touchstone Holdings Ltd | Real estate | 2021 |
| Town & Country Real Estate Ltd | Real estate | 2020 |
| TPJ Construction Ltd | Construction | 2011 |
| Trafi Limited | Information & communication | 2014 |
| Transcend Distribution Specialist Limited | Transport & logistics | 1997 |
| Transferway Ltd | Transport & logistics | 2020 |
| Transport EV Limited | Administrative & support | 2025 |
| Travel Care London Ltd | Transport & logistics | 2024 |
| Travel Centric Technology Ltd | Information & communication | 2008 |
| Travel Indulgence Limited | Administrative & support | 2016 |
| Trends Fusion by Alex Ltd | Extraterritorial | 2024 |
| Triangle Parking Limited | Other services | 2023 |
| Trico International Shipping Ltd | Transport & logistics | 2020 |
| Trident Estates Limited | Professional & scientific | 2012 |
| TRIPL3S Limited | Manufacturing | 2025 |
| Triple a Park Homes Ltd | Real estate | 2018 |
| Triple M Spare Parts Ltd | Wholesale & retail | 2024 |
| Triples Sausages Limited | Manufacturing | 2025 |
| TRM Sidhu Ltd | Transport & logistics | 2020 |
| Trotro Bay Limited | Hospitality | 2024 |
| True and Bare Ltd | Wholesale & retail | 2020 |
| True Top Roofing & Building Ltd | Construction | 2025 |
| Truevital Goods UK Ltd | Wholesale & retail | 2026 |
| Tsaa Holdings Ltd | Professional & scientific | 2024 |
| TSL Cars & Commercials Ltd | Wholesale & retail | 2023 |
| TSS (Property Holdings) Ltd | Real estate | 2016 |
| Tuckmed Ltd | Health & social care | 2023 |
| Tuiuiu Ltd | Information & communication | 2021 |
| Tulyar Technical Services Limited | Real estate | 2017 |
| Turbo Diesel London Limited | Wholesale & retail | 2018 |
| Turismo Limited | Wholesale & retail | 2025 |
| Turnkey Investment Group Ltd | Real estate | 2025 |
| Tutorsvalley Limited | Education | 2015 |
| TW18STAINES Ltd | Households | 2023 |
| TW19 Falcon House RTM Company Limited | Real estate | 2023 |
| Two Naa's Limited | Wholesale & retail | 2022 |
| Two Rivers Builders Ltd | Construction | 2024 |
| UCL Holdings & Investments Limited | Financial services | 2024 |
| UDL Ltd | Real estate | 2007 |
| UGM IT Solutions Limited | Information & communication | 2026 |
| UK Atlantic Ltd | Transport & logistics | 2019 |
| UK Energy Care Alliance Ltd | Administrative & support | 2024 |
| UK Home Developer Ltd | Real estate | 2025 |
| UK Land Development Group Ltd | Real estate | 2021 |
| UK Moveworks Limited | Financial services | 2021 |
| UK Orient Ltd | Real estate | 2014 |
| UK Prime Cars Ltd | Wholesale & retail | 2011 |
| UK Pure Wealth Ltd | Real estate | 2026 |
| Ukas Limited | Administrative & support | 1992 |
| Ukas Pension Trustee Company Ltd | Professional & scientific | 2012 |
| Ukwise Ltd | Wholesale & retail | 2024 |
| Ultimate Fashion Maker UK Ltd | Manufacturing | 2022 |
| Umbrella Guardians Limited | Households | 2025 |
| UMF Technology Consulting Limited | Information & communication | 2011 |
| UMG Consultancy Limited | Information & communication | 2025 |
| Underground Productions Limited | Arts & recreation | 2003 |
| Uniglobe Soft Solutions Ltd | Information & communication | 2025 |
| Unini Productions Limited | Information & communication | 2020 |
| Uniplanoverseaseducationconsultants Limited | Education | 2022 |
| Uniq Ventures Limited | Wholesale & retail | 2016 |
| Unique Apex Solutions Limited | Administrative & support | 2020 |
| Unique Design & Construction Ltd | Construction | 2017 |
| Unique Double Glazing London Ltd | Construction | 2020 |
| Unique Glazing Limited | Construction | 2019 |
| United Kingdom Accreditation Service | Professional & scientific | 1995 |
| Unity Cargo Ltd | Transport & logistics | 2026 |
| Universal Property Network Ltd | Real estate | 2020 |
| UNK Surrey Homecare Services Ltd | Health & social care | 2024 |
| Unstately Homes Ltd | Construction | 2019 |
| Upper Class Chauffeurs Ltd | Transport & logistics | 2025 |
| UPS (UK Holding) Limited | Professional & scientific | 2003 |
| UPS (UK) Limited | Professional & scientific | 1984 |
| UPS Air Couriers of America Limited | Transport & logistics | 1969 |
| UPS Capital Insurance Agency Limited | Financial services | 2018 |
| UPS Global Treasury PLC | Financial services | 1985 |
| UPS Limited | Transport & logistics | 1985 |
| UPS SCS (UK) Limited | Transport & logistics | 1994 |
| Urak Ltd | Real estate | 2023 |
| Urban Alliance Limited | Administrative & support | 2026 |
| Urban Palate Limited | Hospitality | 2025 |
| Urban Wedding Lights Limited | Hospitality | 2019 |
| Utilities and Contractors Limited | Transport & logistics | 2017 |
| UXB Express West UK Limited | Transport & logistics | 2025 |
| Uyore Ltd | Wholesale & retail | 2025 |
| UZ Travel Group Limited | Wholesale & retail | 2024 |
| V & M (Staines) Ltd | Wholesale & retail | 2019 |
| V&F Preston Ltd | Wholesale & retail | 2020 |
| V&S Talent Co Limited | Administrative & support | 2025 |
| V, D'S and Every Kids Dreams Nurseries Limited | Other services | 2013 |
| V-Go Energy Ltd | Manufacturing | 2022 |
| Vagmine Digi Limited | Information & communication | 2024 |
| Vagmine Properties Ltd | Real estate | 2019 |
| Val-Tech Consultancy Limited | Professional & scientific | 2019 |
| Valet Freak Ltd | Administrative & support | 2023 |
| Valetology Limited | Wholesale & retail | 2019 |