| Unique Lifestyle Homes Limited | Professional & scientific | 2013 |
| Unique Property Group Limited | Construction | 2025 |
| Unique Secure Homes Ltd | Construction | 2024 |
| Unique U Barbers Ltd | Other services | 2024 |
| Unit 13 Ventura Place Ltd | Real estate | 2025 |
| Unit 324 Limited | Wholesale & retail | 2024 |
| Unit Base Ltd | Real estate | 2025 |
| Unit-Hedingham Sidecars Ltd | Administrative & support | 2017 |
| Unite Health Ltd | Professional & scientific | 2022 |
| United Gifts Britain Ltd | Wholesale & retail | 2021 |
| Unity Building - Plastering - Glazing Ltd | Construction | 2019 |
| Unity Events Limited | Real estate | 2025 |
| Unity Hospitality Ltd | Hospitality | 2026 |
| Unity School Services Ltd | Administrative & support | 2021 |
| Unitypro Services Ltd | Administrative & support | 2025 |
| Universal Care Ltd | Health & social care | 2024 |
| Universal Maintenance Contracts Limited | Manufacturing | 2008 |
| Universal Quality Care Ltd | Administrative & support | 2022 |
| Universal Spotless Limited | Administrative & support | 2024 |
| Universe 9 Ltd | Arts & recreation | 2024 |
| Untitled Digital Limited | Information & communication | 2015 |
| Unug Ltd | Other services | 2026 |
| Unveil Online Ltd | Information & communication | 2026 |
| Unveiled Threads Ltd | Wholesale & retail | 2026 |
| Unvl Ltd | Information & communication | 2025 |
| UP & Running Bournemouth Limited | Wholesale & retail | 2003 |
| UP2DATE Dating Limited | Information & communication | 2025 |
| Update Electrical Services Ltd | Construction | 2025 |
| Uplands Chiropractic Limited | Health & social care | 2022 |
| Uplands Court Limited | Real estate | 2007 |
| Uplifting Construction Ltd | Construction | 2016 |
| Upper Garden Flats Limited | Households | 1972 |
| Upper Road Flats Management Company Limited | Households | 1978 |
| Upperdog Holdings Limited | Financial services | 2017 |
| Upperdog Ltd | Information & communication | 2013 |
| Upreach Digital Ltd | Information & communication | 2024 |
| Upswing Consulting Ltd | Information & communication | 2021 |
| Upton Beach Consulting Limited | Professional & scientific | 2018 |
| Upton Food & Music Festivals Ltd | Administrative & support | 2025 |
| Upton Oak Gardens Management Limited | Households | 2023 |
| Upton Trading Limited | Wholesale & retail | 2020 |
| Upvc & Glazing Repairs Limited | Construction | 2025 |
| UQ Trade Ltd | Wholesale & retail | 2018 |
| Urban Box Group Ltd | Wholesale & retail | 2017 |
| Urban Electrical (Dorset) Limited | Construction | 2016 |
| Urban Fashionista Ltd | Wholesale & retail | 2022 |
| Urban Garden Limited | Hospitality | 2013 |
| Urban Gardens Holdings Ltd | Financial services | 2022 |
| Urban Interiors (Properties) 2 Limited | Real estate | 2023 |
| Urban Interiors (Properties) Limited | Construction | 2012 |
| Urban Motorbike Ltd | Transport & logistics | 2024 |
| Urban Street Kitchen Ltd | Hospitality | 2025 |
| Urbanski GRP Ltd | Manufacturing | 2022 |
| Urelax Ltd | Other services | 2021 |
| Ursus Interactive Ltd | Information & communication | 2023 |
| Ursynergy Limited | Manufacturing | 2025 |
| Urtle Limited | Professional & scientific | 2017 |
| Urtle Solutions Ltd | Information & communication | 2019 |
| URU2 Aesthetics Ltd | Health & social care | 2025 |
| Urvee Ltd | Wholesale & retail | 2018 |
| Useful Shop Ltd | Other services | 2020 |
| Useinternational Ltd | Administrative & support | 2004 |
| User Friendly Business Solutions Limited | Professional & scientific | 1993 |
| Uskind Ltd | Administrative & support | 2025 |
| UTB Construction Ltd | Construction | 2024 |
| Utopia Estates Ltd | Wholesale & retail | 2025 |
| Utopia Global IT Ltd | Information & communication | 2026 |
| Uwonham Ltd | Information & communication | 2024 |
| UWV Services Ltd | Wholesale & retail | 2011 |
| Uxbridge GC Ltd | Wholesale & retail | 2025 |
| V & a Events Limited | Other services | 2010 |
| V & V Domestic Services Ltd | Administrative & support | 2024 |
| V & V Essential Limited | Wholesale & retail | 2025 |
| V Desi Chai Ltd | Hospitality | 2024 |
| V Motors South Limited | Wholesale & retail | 2025 |
| V&D Cleaning Ltd | Administrative & support | 2022 |
| V&D Spedition Ltd | Construction | 2019 |
| V. O. Consultancy Services Limited | Administrative & support | 2013 |
| V.C. Courier Ltd | Transport & logistics | 2023 |
| V3M Consulting Ltd | Professional & scientific | 2023 |
| V4 Foods Ltd | Wholesale & retail | 2026 |
| VA Solutions Ltd | Administrative & support | 2023 |
| Vaedi Limited | Information & communication | 2016 |
| Vaigai Ltd | Wholesale & retail | 2020 |
| Vais Care Ltd | Health & social care | 2018 |
| VAL Borg Enterprise Ltd | Real estate | 2026 |
| Valcomino Limited | Hospitality | 2012 |
| Valda Properties Limited | Construction | 1960 |
| Vale Court Management (Acton) Limited | Real estate | 1969 |
| Vale Mansions Ltd | Households | 2013 |
| Valenti Partnership Limited | Hospitality | 2022 |
| Valentine Home Improvements Ltd | Construction | 2022 |
| Valeroy Limited | Real estate | 2001 |
| Valetcraft Limited | Professional & scientific | 1934 |
| Valetors Ltd | Information & communication | 2026 |
| Valfam Limited | Professional & scientific | 2014 |
| Valhalla Security Ltd | Administrative & support | 2020 |
| Valiant Homes Limited | Hospitality | 2002 |
| Valkyrie Medical (SW) Ltd | Health & social care | 2023 |
| Valteran Ltd | Wholesale & retail | 2020 |