| UK Hot Bargains Ltd | Wholesale & retail | 2016 |
| UK Marketing Chamber Limited | Professional & scientific | 2025 |
| UK One to One Business Solutions Ltd | Other services | 2012 |
| UK Platinum Installation Ltd | Construction | 2021 |
| UK Property Associates Ltd | Real estate | 2021 |
| UK Real Estate Developers Ltd | Construction | 2024 |
| UK Secure Squad Limited | Administrative & support | 2022 |
| UK Sign & Awning Ltd | Professional & scientific | 2021 |
| UK Symmetry Ltd | Professional & scientific | 2023 |
| UK Telugu Association of Christians | Other services | 2012 |
| UK Trading Hub Limited | Real estate | 2019 |
| UK Travel DMC Ltd | Professional & scientific | 2025 |
| UK Windows & Construction Ltd | Construction | 2016 |
| UK WWL Limited | Transport & logistics | 2018 |
| UK Zonex Ltd | Other services | 2018 |
| Uk-Sylhet Express Ltd | Administrative & support | 2021 |
| UK21PRODUCTION Ltd | Information & communication | 2022 |
| Ukeu Consultancy Ltd | Education | 2025 |
| Ukings Global Limited | Professional & scientific | 2012 |
| Ukonu Ltd | Wholesale & retail | 2024 |
| Ukpor Patriots UK | Education | 2016 |
| Ukremovals Ltd | Transport & logistics | 2025 |
| Ukrishna Limited | Wholesale & retail | 2025 |
| UKTRENDMART60 Ltd | Wholesale & retail | 2025 |
| Ulter Shine Services Ltd | Administrative & support | 2025 |
| Ultimateconnect Ltd | Information & communication | 2024 |
| Ultimax Services Ltd | Other services | 2019 |
| Ultra K9 Security Services Ltd | Wholesale & retail | 2017 |
| Ultrastrip Ltd | Manufacturing | 2026 |
| UM Beijo Ltd | Wholesale & retail | 2022 |
| UM Sunset Ltd | Wholesale & retail | 2026 |
| Umaima M Khan Ltd | Wholesale & retail | 2026 |
| Umair & Afsheen Ltd | Hospitality | 2024 |
| Umar Maintenance Limited | Transport & logistics | 2017 |
| Umecorn Limited | Information & communication | 2024 |
| Umoja Kwanza Limited | Transport & logistics | 2021 |
| UN Sons Ltd | Wholesale & retail | 2025 |
| Unch BEY Ltd | Information & communication | 2023 |
| Unchained Forever Publishing Ltd | Information & communication | 2022 |
| Uncu Transport Ltd | Construction | 2015 |
| Unic Trans Ltd | Transport & logistics | 2022 |
| Unicoolo Ltd | Wholesale & retail | 2023 |
| UNICORN7 Ltd | Health & social care | 2022 |
| Unifiedbeacon Ltd | Wholesale & retail | 2026 |
| Unifuture Group Limited | Financial services | 2025 |
| Unify Hotels Ltd | Hospitality | 2024 |
| Unik Company Services Ltd | Construction | 2016 |
| Unilyf Ltd | Information & communication | 2024 |
| Union Music Group Limited | Extraterritorial | 2016 |
| Union Utilites Ltd | Professional & scientific | 2024 |
| Uniplus Ltd | Wholesale & retail | 2023 |
| Uniq Abode Ltd | Real estate | 2020 |
| Unique 1 Communications Ltd | Information & communication | 2008 |
| Unique 1 Properties Ltd | Real estate | 2013 |
| Unique Barbers Touch Limited | Other services | 2022 |
| Unique Care Services Limited | Extraterritorial | 2021 |
| Unique DEB Ltd | Transport & logistics | 2021 |
| Unique Eclipse Limited | Transport & logistics | 2017 |
| Unique Glow Limited | Other services | 2012 |
| Unique Removals Limited | Transport & logistics | 2010 |
| Unique Shopfitters Limited | Construction | 2018 |
| Uniquefindshop Ltd | Wholesale & retail | 2025 |
| Unitech Solutions Ltd | Wholesale & retail | 2025 |
| United Air Travel Limited | Administrative & support | 2019 |
| United Generation Limited | Health & social care | 2021 |
| United Relief International Club Ltd | Health & social care | 2019 |
| United Rental Services Ltd | Administrative & support | 2016 |
| United Xpress Logistics Limited | Transport & logistics | 2023 |
| UNITED1 Ltd | Wholesale & retail | 2024 |
| Unitedfields Limited | Construction | 2023 |
| Unity Means Everything Ltd | Wholesale & retail | 2025 |
| Unity Trade Services UK Limited | Transport & logistics | 2019 |
| Universal Colors Ltd | Administrative & support | 2020 |
| Universal Empire Ltd | Education | 2019 |
| Universal Makers Ltd | Professional & scientific | 2024 |
| Universal of Catering Limited | Hospitality | 2025 |
| Universal School of London Ltd | Education | 2024 |
| Universal Trans Services UK Limited | Transport & logistics | 2018 |
| Unlimited Education Academy UK Ltd | Education | 2020 |
| UNT2UNT(US Never Them) Ltd | Manufacturing | 2025 |
| Unveil Treat Clinic Ltd | Other services | 2026 |
| UP Skilled Ltd | Education | 2019 |
| Upper Lounge Ltd | Hospitality | 2026 |
| Upsqill Ltd | Information & communication | 2022 |
| Upvc & Aluminium Trade Supply Ltd | Wholesale & retail | 2021 |
| UR Fast Food Ltd | Hospitality | 2023 |
| Uratta Constructions Limited | Construction | 2023 |
| Urban Brass Hardware Ltd | Wholesale & retail | 2023 |
| Urban Habitation Ltd | Real estate | 2023 |
| Urban Hire Ltd | Administrative & support | 2024 |
| Urban Regenerate Homes Ltd | Construction | 2026 |
| Urban Utopia 1 Ltd | Wholesale & retail | 2025 |
| Urbanaura Retail Ltd | Wholesale & retail | 2026 |
| Urbanhivz Ltd | Wholesale & retail | 2025 |
| Urbanlane London Ltd | Real estate | 2021 |
| Uromak Solutions Limited | Financial services | 2018 |
| URS Solutions Limited | Transport & logistics | 2025 |
| USA Car Dealers Ltd | Wholesale & retail | 2018 |
| Usaid Ltd | Wholesale & retail | 2026 |
| Ustoni Ltd | Wholesale & retail | 2024 |