| Twinbyte Consultant Limited | Information & communication | 2025 |
| Twinklestars Montessori Nursery Ltd | Education | 2010 |
| Twins Plastering Ltd | Construction | 2024 |
| Twinspin Transport Limited | Transport & logistics | 2026 |
| Two Horns Ltd | Financial services | 2020 |
| Two IK Ltd | Real estate | 2022 |
| Two Kites Production Limited | Information & communication | 2009 |
| Twocan Psychology Services Ltd | Health & social care | 2018 |
| Twong Consulting Ltd | Professional & scientific | 2025 |
| Twydles Limited | Professional & scientific | 2010 |
| TXR Property Investments Limited | Real estate | 2022 |
| Tyler Home Renovations Ltd | Construction | 2022 |
| Tylersfield Freehold Limited | Households | 2003 |
| Tylersfield Management Company Limited | Households | 1988 |
| Tyre Group UK Limited | Wholesale & retail | 2015 |
| Tyretick Ltd | Wholesale & retail | 2025 |
| Tzwt Limited | Real estate | 2016 |
| U Awan Ltd | Financial services | 2022 |
| U G C Global Services Limited | Administrative & support | 2018 |
| U React CIC | Education | 2024 |
| UAK Consulting Ltd | Professional & scientific | 2022 |
| Ubani Ltd | Information & communication | 2023 |
| Uber Funding Ltd | Financial services | 2022 |
| Uber Tutors Ltd | Education | 2013 |
| Ubinetics Limited | Administrative & support | 2005 |
| Ubiqa Global Ascent Limited | Wholesale & retail | 2025 |
| Ubiviz Ltd | Other services | 2020 |
| Ubuntu Website Development Limited | Professional & scientific | 1999 |
| Ucode Consulting Limited | Information & communication | 2017 |
| UCU Brick Restoration Limited | Construction | 2025 |
| Udaari Limited | Health & social care | 2016 |
| Uddin Consultancy Services Ltd | Professional & scientific | 2024 |
| Udlr Express Ltd | Administrative & support | 2025 |
| Uiduk Ltd | Real estate | 2011 |
| Uiux Studio Ltd | Information & communication | 2024 |
| Ujetrans Ltd | Construction | 2025 |
| UK Calibre Auto Parts Ltd | Wholesale & retail | 2023 |
| UK City Delivery Service Ltd | Transport & logistics | 2022 |
| UK City Property Limited | Construction | 2014 |
| UK Company for Entertainment Centers Limited | Arts & recreation | 2022 |
| UK Content Design Ltd | Information & communication | 2018 |
| UK Demes Ltd | Manufacturing | 2017 |
| UK Dream Drive Ltd | Transport & logistics | 2025 |
| UK Eventx Ltd | Administrative & support | 2026 |
| UK Family Properties Ltd | Real estate | 2015 |
| UK Fast Track Marketing Ltd. | Other services | 2009 |
| UK Glass Fittings Ltd | Extraterritorial | 2017 |
| UK Glass Limited | Manufacturing | 2012 |
| UK International United Research Co. Limited | Information & communication | 2020 |
| UK Link Enterprises Ltd | Wholesale & retail | 2024 |
| UK Local Locksmiths Ltd | Manufacturing | 2022 |
| UK Mega Foods Ltd | Hospitality | 2024 |
| UK Mortgage Finders Limited | Financial services | 2016 |
| UK Omnibus Group Limited | Other services | 2025 |
| UK Pillars Group Ltd | Wholesale & retail | 2026 |
| UK Prop-Fix Limited | Construction | 2024 |
| UK Property Futures Limited | Construction | 2010 |
| UK Recovery Ltd | Other services | 2013 |
| UK Taste Ltd | Hospitality | 2017 |
| UK THG Ltd | Health & social care | 2022 |
| UK Travel Store Ltd | Administrative & support | 2018 |
| UK Truck Ltd | Wholesale & retail | 2023 |
| Uk-China Fashion Arts and Culture Ltd | Arts & recreation | 2019 |
| Uk.Medica Limited | Wholesale & retail | 2015 |
| UKA Scaffolding Ltd | Construction | 2025 |
| Ukcndea Group Limited | Arts & recreation | 2024 |
| Ukperaj Ltd | Construction | 2024 |
| Ultasound Solutions Limited | Health & social care | 2015 |
| Ultima FM Ltd | Administrative & support | 2025 |
| Ultimate Branding Ltd | Wholesale & retail | 2010 |
| Ultimate Car Detailing Ltd | Wholesale & retail | 2025 |
| Ultimate Diamond Solutions Limited | Information & communication | 2019 |
| Ultimate Facility Management Ltd | Administrative & support | 1996 |
| Ultimate Strongman Productions Limited | Information & communication | 2010 |
| Ultra Slim Limited | Other services | 1983 |
| Ultra-Sound Investments Ltd | Real estate | 1999 |
| Ultrasoft Solutions Ltd | Wholesale & retail | 2024 |
| Ultrasonic Vascular Imaging Ltd. | Public administration | 2013 |
| Ultrasound Image Studio Ltd | Health & social care | 2018 |
| Ulus Land Limited | Real estate | 2017 |
| Ulus Pharma Ltd | Wholesale & retail | 2024 |
| ULW Limited | Manufacturing | 2021 |
| Umaben D Desai Ltd | Professional & scientific | 2022 |
| Umaom Properties Ltd | Real estate | 2021 |
| UMG & Partners Limited | Professional & scientific | 2022 |
| Umoosa Ltd | Wholesale & retail | 2026 |
| UNA Egan Ltd | Financial services | 2025 |
| Unavts UK Limited | Financial services | 2019 |
| Unavts UK Midco Limited | Financial services | 2026 |
| Uncle John Limited | Professional & scientific | 2009 |
| Uncultured Collective Ltd | Professional & scientific | 2021 |
| Under Pressure Jetting Ltd | Administrative & support | 2025 |
| Understand and Deliver Limited | Administrative & support | 2015 |
| Unesta Homes Limited | Construction | 2025 |
| Unibase Limited | Other services | 2010 |
| Unicorn Food Ltd | Hospitality | 2025 |
| Uniflora Ltd | Wholesale & retail | 2015 |
| Unifound Limited | Construction | 2021 |
| Unik Accountancy Services Ltd | Professional & scientific | 2010 |
| Union Business Finance Holdings Limited | Extraterritorial | 2025 |