| Trinity Chase (Ware) Management Company Limited | Households | 2006 |
| Trinity Threads Collective Ltd | Manufacturing | 2025 |
| Triple H Inc. Ltd | Professional & scientific | 2016 |
| Triple M & E Properties Limited | Real estate | 1999 |
| Triple Play Labs Ltd | Information & communication | 2025 |
| Tripple Consulting Ltd | Professional & scientific | 2016 |
| Trolabi Group Limited | Information & communication | 2019 |
| Trounuk Consulting Limited | Professional & scientific | 2025 |
| Trudgill & SON Ltd | Wholesale & retail | 2019 |
| Truffle Property Investments Limited | Real estate | 2020 |
| Trustbuild Connect Ltd | Construction | 2024 |
| Truver Ltd. | Information & communication | 2015 |
| TSL Dental Laboratory Ltd | Manufacturing | 2018 |
| Ttbu Properties Ltd | Real estate | 2016 |
| Tuamgraney Ltd | Other services | 2019 |
| Tugwoods Plant Hire Limited | Water & waste | 2011 |
| Tunbridge Property Ltd | Construction | 2014 |
| Turtle Trust Limited | Professional & scientific | 2021 |
| Tutor First Ltd | Education | 2019 |
| TVK Properties Ltd | Real estate | 2024 |
| TWC Technology Limited | Information & communication | 2015 |
| Twenty One Taras (UK) Limited | Other services | 2024 |
| Twin Brickwork Ltd | Construction | 2002 |
| Twin Pine Media Ltd | Information & communication | 2010 |
| Twin Systems Holdings (UK) Limited | Professional & scientific | 1996 |
| Twin Systems Limited | Information & communication | 1988 |
| Twins Estates (London) Limited | Construction | 2014 |
| Twins Estates Limited | Financial services | 2014 |
| Two Social Limited | Extraterritorial | 2015 |
| Twozand Limited | Information & communication | 2016 |
| Twyford Mill Management Company Limited | Households | 1988 |
| Typical Italian Property Ltd | Real estate | 2023 |
| Tyrell VFX Limited | Information & communication | 2013 |
| Tåle Creative Ltd | Arts & recreation | 2026 |
| U&N Property Limited | Real estate | 2024 |
| UA Team (Fashion) Ltd | Wholesale & retail | 2024 |
| UAV Engineering Ltd | Administrative & support | 2019 |
| Ucapital Investment Ltd | Financial services | 2021 |
| Ucapital Ltd | Administrative & support | 2016 |
| UCAPITAL24 Ltd | Administrative & support | 2017 |
| UK Blue Armour Ltd | Information & communication | 2026 |
| UK Boxing Holdings Ltd | Arts & recreation | 2019 |
| UK Care (Special Needs) Limited | Health & social care | 2013 |
| UK Decor Ltd | Construction | 2012 |
| UK Design & Build Limited | Construction | 2017 |
| UK Hole in One Limited | Financial services | 2013 |
| UK Hotels 1 Ltd | Real estate | 2021 |
| UK Hotels 2 Ltd | Real estate | 2021 |
| UK Resin Floors Ltd | Construction | 2020 |
| UK Surplus Direct Ltd | Wholesale & retail | 2026 |
| UK2 Management Limited | Administrative & support | 2024 |
| UKK Properties Limited | Real estate | 2016 |
| UKO Asset Management Ltd | Other services | 2019 |
| UKO Land and Site Services Ltd | Construction | 2018 |
| Ultra Clean Services Limited | Households | 2021 |
| Umbrella Management Solutions Limited | Administrative & support | 2015 |
| Under Milk Wood Limited | Real estate | 2018 |
| Underfoot Flooring Limited | Wholesale & retail | 2003 |
| Understated Limited | Other services | 2017 |
| Union Scrap Metals Limited | Water & waste | 2017 |
| Unique by Aisleyne Ltd | Wholesale & retail | 2007 |
| Unique Interiors Ltd | Construction | 1997 |
| United Eagles Ltd | Construction | 2022 |
| United Forces Limited | Administrative & support | 2014 |
| United Motor Sports Club Ltd | Arts & recreation | 2022 |
| United Smart Ltd | Administrative & support | 2015 |
| Universal City Limited | Real estate | 2025 |
| Universal Enterprise & Trade, Ltd. | Construction | 2007 |
| Universe John Ltd | Administrative & support | 2023 |
| Unmatched Club Ltd | Hospitality | 2025 |
| Upgrade Technology Engineering Ltd | Professional & scientific | 2005 |
| Upturn Solutions Limited | Construction | 2015 |
| Urban Moves Limited | Real estate | 2000 |
| Urban R+D Limited | Construction | 2021 |
| Urban Square Limited | Construction | 2013 |
| USK Hotel Limited | Hospitality | 2023 |
| Utaram Limited | Wholesale & retail | 2018 |
| UTS Move Managers Limited | Other services | 1993 |
| Uvex World Systems Limited | Manufacturing | 1985 |
| V 1 P Limited | Wholesale & retail | 2018 |
| V Twin Castings Limited | Manufacturing | 2001 |
| V12 Motorsport UK Limited | Wholesale & retail | 2023 |
| Vakis Energy Limited | Construction | 2016 |
| Valhalla Funk Ltd | Information & communication | 2024 |
| Vamm Holding Ltd | Real estate | 2022 |
| Van OS & Co. Limited | Construction | 2012 |
| Vanessa Margaret Bennett Ltd | Extraterritorial | 2023 |
| Vanguard Consultants and Services Ltd | Administrative & support | 2025 |
| Vann International Ltd | Wholesale & retail | 2019 |
| Vantex Trimmings Ltd | Wholesale & retail | 2018 |
| Vascular Sonographic DS Limited | Health & social care | 2011 |
| Vata Groundworks Ltd | Construction | 2021 |
| VCM02 Services Ltd | Professional & scientific | 2025 |
| VEL (UK) Ltd | Extraterritorial | 2012 |
| Vela Care Group Ltd | Administrative & support | 2026 |
| Velostreets Limited | Professional & scientific | 2022 |
| Venice Landmark Group Ltd | Administrative & support | 2024 |
| Venn Construction Limited | Administrative & support | 2017 |
| Ventry Care Homes Limited | Health & social care | 2009 |
| Ventry Care Limited | Health & social care | 2009 |