| U.M.W. Ltd. | Manufacturing | 1997 |
| UA1 Solutions Ltd | Transport & logistics | 2014 |
| Uahidesuk Ltd | Wholesale & retail | 2025 |
| Uandi Consult Ltd | Professional & scientific | 2025 |
| Ubbink (U.K.) Limited | Wholesale & retail | 1974 |
| Ucee Qualitty Foods Limited | Wholesale & retail | 2024 |
| Uchemac Ltd | Administrative & support | 2015 |
| Ucho Limited | Administrative & support | 2015 |
| Ucrave Limited | Wholesale & retail | 2011 |
| Uddheshya Studio UK Ltd | Information & communication | 2025 |
| Udeskole Play Ltd | Manufacturing | 2025 |
| UFB Food Ltd | Hospitality | 2023 |
| Ufsa Ltd | Transport & logistics | 2020 |
| Ufsal Limited | Transport & logistics | 2025 |
| Ufulu Ltd | Financial services | 2017 |
| UG Trans Ltd | Transport & logistics | 2015 |
| Ugen Holistic Limited | Wholesale & retail | 2018 |
| Ugohcent Limited | Health & social care | 2020 |
| Uhuru Worldwide Ltd | Professional & scientific | 2016 |
| UIX LAB Ltd | Information & communication | 2012 |
| Ujana-Kandake Akosua Hutchinson-Sharpe Limited | Extraterritorial | 2021 |
| UK 3FLOOR Ltd | Other services | 2014 |
| UK Advanced Industrials Ltd | Other services | 2020 |
| UK Bench & Fence Painting Ltd | Construction | 2015 |
| UK Brand Sales Limited | Hospitality | 2009 |
| UK Business Forums Limited | Administrative & support | 2024 |
| UK Comms Cabling Limited | Manufacturing | 2024 |
| UK Compass Ltd | Information & communication | 2023 |
| UK Compressed Air Services Ltd | Administrative & support | 2023 |
| UK Connekt Ltd | Construction | 2018 |
| UK Consulting Plus Ltd | Professional & scientific | 2015 |
| UK Courier Link Ltd | Transport & logistics | 2008 |
| UK Digital Accountant Ltd | Professional & scientific | 2023 |
| UK Dragonfly Logistics Limited | Transport & logistics | 2022 |
| UK Education in Iraq Limited | Education | 2021 |
| UK Evas Ltd | Transport & logistics | 2024 |
| UK Fast Express Ltd | Transport & logistics | 2024 |
| UK Film School C.I.C. | Education | 2006 |
| UK GAS Transportation Limited | Professional & scientific | 2009 |
| UK Interior & Design Ltd | Hospitality | 2018 |
| UK Land & Property Holdings Ltd | Financial services | 2022 |
| UK Linen & Laundry Limited | Other services | 2010 |
| UK Livelines Limited | Information & communication | 2003 |
| UK Loft Insulation Solutions Ltd | Construction | 2023 |
| UK Magic Judges Limited | Administrative & support | 2015 |
| UK MO Berry Ltd | Wholesale & retail | 2017 |
| UK Monopole Store Ltd | Wholesale & retail | 2023 |
| UK Mstore Ltd | Wholesale & retail | 2026 |
| UK Nails Northampton Ltd | Other services | 2023 |
| UK National Recruitment Solutions Limited | Administrative & support | 2023 |
| UK Organ Donation and Transplantation Research Network C.I.C. | Education | 2026 |
| UK Poppy Products Limited | Manufacturing | 2009 |
| UK Power Distribution Limited | Energy | 2007 |
| UK Project Services Group Limited | Professional & scientific | 2020 |
| UK Radon Centres Limited | Manufacturing | 2023 |
| UK Regulatory Licencing Limited | Administrative & support | 2016 |
| UK Research and Consultancy Services Limited | Professional & scientific | 2013 |
| UK Strategic Land Limited | Real estate | 2020 |
| UK Truck Planner Limited | Transport & logistics | 2018 |
| UK Turbo Speed Logistics Ltd | Transport & logistics | 2026 |
| UK Wide Remedial Repair Services Ltd | Construction | 1978 |
| Uk-Global-Trans Ltd | Transport & logistics | 2025 |
| Uk.Poland Trade Limited | Wholesale & retail | 2023 |
| UKB4C Limited | Wholesale & retail | 2017 |
| Ukelitesports Ltd | Education | 2018 |
| Ukesg Limited | Arts & recreation | 2019 |
| UKG BB Holdings Ltd | Manufacturing | 2025 |
| UKG BB Ltd | Manufacturing | 2026 |
| Uksevenseas Ltd | Administrative & support | 2020 |
| Ukulele Cleaning Company | | 1999 |
| Uljanagric Boutique Ltd | Wholesale & retail | 2025 |
| Ullka Limited | Transport & logistics | 2014 |
| Ultimate Care Homes Limited | Real estate | 2020 |
| Ultimate Fencing Ltd | Manufacturing | 2022 |
| Ultimate Foods Ltd | Hospitality | 2025 |
| Ultimate Football Breaks Ltd | Wholesale & retail | 2025 |
| Ultimate Football Raffles Ltd | Wholesale & retail | 2026 |
| Ultimate Logistics Limited | Transport & logistics | 2015 |
| Ultimate Performance Limited | Manufacturing | 2003 |
| Ultimate PM Solutions Limited | Professional & scientific | 2026 |
| Ultimate Solutions Holding Ltd | Financial services | 2024 |
| Ultimate Solutions Ltd | Manufacturing | 2011 |
| Ultimate Warbirds Ltd | Extraterritorial | 2019 |
| Ultimateworkz Ltd | Other services | 2021 |
| Ultra Biotecs Limited | Manufacturing | 2011 |
| Ultra Flavours Ltd | Hospitality | 2025 |
| Ultra Secure Holdings Limited | Financial services | 2023 |
| Ultradave Cleaning Services Ltd | Administrative & support | 2024 |
| Ultramotive Consultants Limited | Real estate | 2018 |
| Ulysse Advisory Ltd | Professional & scientific | 2019 |
| Umar Zayan Properties Ltd | Real estate | 2024 |
| Umbra Creations Ltd | Information & communication | 2024 |
| Umbrella Fair Organisation Ltd. | Health & social care | 2008 |
| UMK Ltd | Wholesale & retail | 2020 |
| Umk.Transport Limited | Transport & logistics | 2012 |
| Umobile Limited | Wholesale & retail | 2025 |
| Umrah Express Northampton Ltd | Wholesale & retail | 2024 |
| Umrah Supermarket Northampton Ltd | Wholesale & retail | 2022 |
| UN Summer School Ltd | Education | 2024 |
| Unboundlocal Ltd | Information & communication | 2016 |