| UK Camera Store Limited | Wholesale & retail | 2004 |
| UK Casino Guide Limited | Extraterritorial | 2017 |
| UK Chenguan Network Trade Ltd | Information & communication | 2025 |
| UK Cocktail Company Limited | Extraterritorial | 2015 |
| UK Cooling Solutions Ltd | Construction | 2004 |
| UK CV Writing Services Ltd | Administrative & support | 2024 |
| UK Daffodil Care C.I.C. | Health & social care | 2022 |
| UK Dental Specialists Limited | Health & social care | 2017 |
| UK Direct Metals Ltd. | Wholesale & retail | 2015 |
| UK Divine Construction Ltd | Construction | 2026 |
| UK Dressage Ltd | Agriculture & fishing | 2024 |
| UK Expedite Ltd | Wholesale & retail | 2018 |
| UK Facilities Management & Solutions Limited | Administrative & support | 2025 |
| UK Fanxing Culture Trade Ltd | Administrative & support | 2025 |
| UK Fireworks (Retail) Ltd | Wholesale & retail | 2006 |
| UK Floor Cleaning Machines Limited | Wholesale & retail | 2018 |
| UK Floor Shop Limited | Wholesale & retail | 2014 |
| UK Flooring (MK) Limited | Construction | 2015 |
| UK Great Helper Limited | Other services | 2020 |
| UK Infra Services Ltd | Construction | 2025 |
| UK Jason International Cultural Media Limited | Wholesale & retail | 2024 |
| UK JU Feng Culture Ltd | Professional & scientific | 2025 |
| UK Lorries Limited | Wholesale & retail | 2009 |
| UK NEO International Cultural Media Limited | Wholesale & retail | 2024 |
| UK Nobody Left Behind C.I.C. | Health & social care | 2024 |
| UK Orange Magic Cube Information Technology Co., Ltd | Information & communication | 2022 |
| UK Oven Cleaners Limited | Administrative & support | 2011 |
| UK Phoenix Media Ltd | Wholesale & retail | 2025 |
| UK Qian an Media Ltd | Professional & scientific | 2025 |
| UK Retrofit Solutions Limited | Construction | 2021 |
| UK Smart Tech Limited | Other services | 2017 |
| UK Solar Express Limited | Construction | 2025 |
| UK Star MK Limited | Other services | 2024 |
| UK Star Security Limited | Other services | 2002 |
| UK Study Guide Ltd | Professional & scientific | 2021 |
| UK Tamil Muslims CIC | Professional & scientific | 2024 |
| UK Tattoo Fest Ltd | Other services | 2018 |
| UK Taxi Ltd | Transport & logistics | 2022 |
| UK Teng Peng Media Ltd | Professional & scientific | 2025 |
| UK Translate Bureau Ltd | Professional & scientific | 2022 |
| UK Translogistics Ltd | Transport & logistics | 2018 |
| UK Trend Luxe Ltd | Real estate | 2025 |
| UK Vape Direct Limited | Wholesale & retail | 2018 |
| UK Waste Recycling Ltd | Water & waste | 2018 |
| UK Winjie Ltd | Wholesale & retail | 2021 |
| Uk-Dalian Business Association | Health & social care | 2016 |
| Ukenroll Ltd | Education | 2024 |
| Ukhan & Sons Limited | Construction | 2024 |
| Ukki Properties Ltd | Real estate | 2018 |
| Uksev Ltd | Manufacturing | 2025 |
| Uksummit CIC | Other services | 2025 |
| Ulez Recovery & Logistics Ltd | Transport & logistics | 2020 |
| ULS Properties Limited | Real estate | 2023 |
| Ultenic UK Ltd | Wholesale & retail | 2020 |
| Ultima Financials Limited | Professional & scientific | 2017 |
| Ultimate Airport Transfers Ltd | Transport & logistics | 2023 |
| Ultimate Bike Transporter Limited | Extraterritorial | 2021 |
| Ultimate Business Solutions Limited | Health & social care | 2016 |
| Ultimate Cars and Classics Limited | Wholesale & retail | 2018 |
| Ultimatelootdrop Ltd | Wholesale & retail | 2025 |
| Ultra Cards Ltd | Wholesale & retail | 2023 |
| Ultra Construction & Maintenance Limited | Construction | 2023 |
| Ultra Krav Maga Spartans Limited | Education | 2021 |
| Ultra Logistics Limited | Transport & logistics | 2020 |
| Ultra Surefire Limited | Construction | 2004 |
| Ultra Trading Solutions Ltd | Wholesale & retail | 2024 |
| Ultra Training Limited | Health & social care | 2025 |
| Ultra U.K. Limited | Financial services | 2025 |
| Ultrabay Limited | Wholesale & retail | 2021 |
| Ultraflexdynamics Limited | Wholesale & retail | 2024 |
| Ultraheat Limited | Extraterritorial | 1993 |
| Ultravegas Donate 2 Dance CIC | Arts & recreation | 2026 |
| Umair Blue AK Ltd | Wholesale & retail | 2026 |
| Umair United Ltd | Administrative & support | 2025 |
| Uman Ltd | Information & communication | 2024 |
| Umar Gull Ltd | Wholesale & retail | 2025 |
| Umbra Solutions Ltd | Professional & scientific | 2023 |
| Umeda Holdings UK Limited | Financial services | 2022 |
| UMI Computers Ltd | Manufacturing | 2015 |
| Umusa Group Ltd | Wholesale & retail | 2025 |
| Umware Limited | Information & communication | 2015 |
| Unbound Ideas Limited | Professional & scientific | 2025 |
| Unclottable Ltd | Education | 2025 |
| Uncommon Sense Holdings UK Limited | Financial services | 2018 |
| Unconventional Consulting Limited | Extraterritorial | 2024 |
| Under 1 Roof (International) Ltd | Real estate | 2010 |
| Under 1 Roof Maintenance Limited | Construction | 2023 |
| Underground Leak Solutions Ltd | Construction | 2006 |
| Understanding Money Program CIC | Education | 2020 |
| Undugu Ltd | Real estate | 2022 |
| Unhallowed Supply Co Ltd | Professional & scientific | 2023 |
| Unhung Art Limited | Wholesale & retail | 2005 |
| Unibiz Ltd | Wholesale & retail | 2025 |
| Uniblock Ltd | Construction | 2016 |
| Unico (UK) Ltd. | Manufacturing | 1988 |
| Unicom Insurance Services Limited | Financial services | 1993 |
| Unicorn Medics Limited | Health & social care | 2018 |
| Unicorn Networld Ltd | Transport & logistics | 2012 |
| Unics Construction Ltd | Administrative & support | 2019 |
| Unicus Infotech Limited | Information & communication | 2019 |