| TWT Property Group Ltd | Real estate | 2020 |
| TY Glyndwr Cyfyngedig | Hospitality | 2016 |
| Tygavac Advanced Materials Ltd | Extraterritorial | 2022 |
| Tyler James Distribution Ltd | Wholesale & retail | 2022 |
| Tyre Direct Centre Limited | Wholesale & retail | 2025 |
| Tyre Network Limited | Wholesale & retail | 2024 |
| Tyre Zone Oldham Limited | Wholesale & retail | 2017 |
| Tyres and Wheel Junction Ltd | Wholesale & retail | 2024 |
| Tyrion Security Bidco Limited | Financial services | 2014 |
| Tyrion Security Debtco Limited | Financial services | 2014 |
| Tyrion Security Midco Limited | Financial services | 2014 |
| Tyrion Security Topco Limited | Financial services | 2014 |
| Tyro Cleaners Limited | Wholesale & retail | 1978 |
| Tyson Enterprise Ltd | Wholesale & retail | 2025 |
| TZZ Ltd | Wholesale & retail | 2022 |
| U Drive Performance Group Ltd | Administrative & support | 2020 |
| U Flex Trading Ltd | Wholesale & retail | 2019 |
| U&A Transportation Ltd | Transport & logistics | 2024 |
| UAM Enterprise Ltd | Wholesale & retail | 2024 |
| UB Estore Ltd | Wholesale & retail | 2024 |
| UB International Limited | Wholesale & retail | 2025 |
| Ubaydur Rahman Properties Ltd | Real estate | 2025 |
| Ubiquity FM Limited | Wholesale & retail | 2015 |
| Ubuntu Care Collective UK CIC | Public administration | 2026 |
| Ubuy Ltd | Wholesale & retail | 2017 |
| Uddin Tech Ltd | Information & communication | 2022 |
| Udela Designs Ltd | Manufacturing | 2026 |
| UFC Fittonhill Ltd | Wholesale & retail | 2026 |
| UFS Smart Market Ltd | Wholesale & retail | 2026 |
| UGI Limo Limited | Transport & logistics | 2024 |
| Uhlanga Club Properties Ltd | Real estate | 2025 |
| UHS Manchester Limited | Other services | 2018 |
| UJ Trading Ltd | Wholesale & retail | 2017 |
| UJS Marketing Ltd | Wholesale & retail | 2024 |
| UK Best Deal Limited | Wholesale & retail | 2012 |
| UK Bins Limited | Manufacturing | 2024 |
| UK Bucharest Shop Limited | Wholesale & retail | 2026 |
| UK Choice Ltd | Wholesale & retail | 2024 |
| UK Clearance Stock Limited | Wholesale & retail | 2021 |
| UK Creations Ltd | Wholesale & retail | 2022 |
| UK Electrical Contracting Ltd | Construction | 2018 |
| UK Entrance Mats Limited | Manufacturing | 2015 |
| UK Event Holdings Limited | Financial services | 2022 |
| UK Facilities & Maintenance Limited | Manufacturing | 1998 |
| UK Fascias Limited | Construction | 2013 |
| UK Mattress Warehouse Ltd | Wholesale & retail | 2026 |
| UK Media Publishing Limited | Information & communication | 2000 |
| UK Moda Limited | Wholesale & retail | 2024 |
| UK Property Investment Challenge Ltd | Real estate | 2018 |
| UK Property Partners Ltd | Real estate | 2026 |
| UK Puzzle Association | Arts & recreation | 2010 |
| UK Resin Drives Limited | Construction | 2016 |
| UK Roofers Ltd | Construction | 2024 |
| UK Rubber Exports Ltd | Wholesale & retail | 2021 |
| UK Storage Options Ltd | Transport & logistics | 2022 |
| UK Superfold Ltd | Construction | 2013 |
| UK Training and Education Stockton Heath Ltd | Education | 2022 |
| Uk's Hand Car Wash Ltd | Administrative & support | 2019 |
| Ukaz Distribution Ltd | Wholesale & retail | 2024 |
| UKC Bodywork Repair Ltd | Wholesale & retail | 2020 |
| Ukhomecrafts Ltd | Wholesale & retail | 2026 |
| Ukmoffice Ltd | Other services | 2024 |
| UKO Link Ltd | Information & communication | 2022 |
| Ukshutters and Curtains Ltd | Other services | 2026 |
| Ullah Estates Ltd | Real estate | 2024 |
| Ulsd Property Group Ltd | Real estate | 2024 |
| Ultima Acquisition GB Limited | Financial services | 2012 |
| Ultima Holding Limited | Financial services | 2016 |
| Ultimate BM Ltd | Wholesale & retail | 2021 |
| Ultimate Healthcare Solutions Ltd | Administrative & support | 2024 |
| Ultimate Products EBT Ltd | Wholesale & retail | 2021 |
| Ultimate Products PLC | Professional & scientific | 2005 |
| Ultimate Products UK Limited | Wholesale & retail | 1997 |
| Ultimate Roofing and Building Products Ltd | Manufacturing | 2020 |
| Ultimate Upvc (NW) Ltd | Manufacturing | 2020 |
| Ultisyn Ltd | Wholesale & retail | 2022 |
| Ultra Stainless Steel Polishing Limited | Manufacturing | 2012 |
| ULTRA98 Ltd | Administrative & support | 2018 |
| Ultrane Development Ltd | Information & communication | 2024 |
| Ultrus Ltd | Information & communication | 2020 |
| Ulysses Communications & Promotions Limited | Professional & scientific | 2003 |
| UM ENT. Ltd | Administrative & support | 2017 |
| UM Legal Ltd | Professional & scientific | 2023 |
| UM Logistics Ltd | Transport & logistics | 2021 |
| UM UK Motors Ltd | Wholesale & retail | 2024 |
| Um&Co Global Edge Legal and Financial Advisers Ltd | Professional & scientific | 2026 |
| Umaa Logistics Ltd | Transport & logistics | 2026 |
| Umar Enterprises Ltd | Wholesale & retail | 2019 |
| Umar Rasool Limited | Health & social care | 2023 |
| Umer Food Store Ltd | Wholesale & retail | 2022 |
| Ummah Welfare Foundation | Health & social care | 2012 |
| Umskfi 2012 Ltd | Financial services | 2024 |
| Umskif 2K12 Limited | Financial services | 2024 |
| Uncles Tea HUT Limited | Hospitality | 2022 |
| Unclez T HUT Ltd | Manufacturing | 2026 |
| Under Pressure POD Ltd | Health & social care | 2026 |
| Underground Express Ltd | Arts & recreation | 2020 |
| Understairs Ltd | Manufacturing | 2026 |
| Unibrands Global Limited | Wholesale & retail | 2025 |
| Unic Cranes (Europe) Limited | Extraterritorial | 2003 |