| Tripidy Limited | Real estate | 2023 |
| Triple 8 Consulting Limited | Real estate | 2016 |
| Triple 8 Ltd | Administrative & support | 2023 |
| Triple N Resources Ltd | Wholesale & retail | 2024 |
| Trnds Ltd | Wholesale & retail | 2021 |
| Trofin Construction Ltd | Construction | 2023 |
| Tropicool Limited | Construction | 2005 |
| Trsl Property Enterprises Ltd | Real estate | 2018 |
| Trueore Limited | Information & communication | 2024 |
| Trukon Limited | Transport & logistics | 2025 |
| Trusted Logistics & Recycling Ltd | Transport & logistics | 2025 |
| Trymamma Ltd | Wholesale & retail | 2025 |
| TS Contracts Ltd | Construction | 2001 |
| TS Discounts Ltd | Wholesale & retail | 2023 |
| TS Investment (London) Limited | Hospitality | 2024 |
| TSE Engineering Pharma Consultant Limited | Professional & scientific | 2026 |
| Tsll Ltd | Wholesale & retail | 2026 |
| TSM Building Services Ltd | Construction | 2020 |
| TSM Premier Properties Limited | Real estate | 2025 |
| TSW Joinery Solutions Limited | Construction | 2010 |
| TTL Property Management LLP | | 2025 |
| Ttne Limited | Administrative & support | 2018 |
| TU TIN Ltd | Hospitality | 2023 |
| Tuitiontailors Ltd | Education | 2026 |
| TUK TUK Hornchurch Ltd | Hospitality | 2022 |
| Tunc Fish & Chips Ltd | Hospitality | 2026 |
| Turtle Tots South Essex Ltd | Education | 2018 |
| Tutum Holdings Ltd | Real estate | 2018 |
| Tutum Homes Ltd | Real estate | 2019 |
| Tutum Management Ltd | Real estate | 2017 |
| TVP Plumbing & Heating Ltd | Construction | 2019 |
| TW Utilities & Plant Hire Ltd | Construction | 2019 |
| Twin Bell Ltd | Real estate | 2020 |
| Twinkly Eyes Photography Limited | Professional & scientific | 2026 |
| Twinning IT UK Limited | Other services | 2020 |
| Twins Dustless Blasting Ltd | Construction | 2017 |
| Twisted Prints (Specialty) Limited | Manufacturing | 2022 |
| Twitch Marketing Limited | Professional & scientific | 2019 |
| Two Brothers Locksmiths LLP | | 2022 |
| Two Step Finance Ltd | Professional & scientific | 2017 |
| Two Step Management Consulting Limited | Professional & scientific | 2019 |
| Two Year Break Limited | Arts & recreation | 2018 |
| Two-Bry Limited | Real estate | 2012 |
| TX Management Limited | Real estate | 2020 |
| Tyler Accountancy Services Limited | Professional & scientific | 2014 |
| Tymless Properties Limited | Real estate | 2023 |
| Typecast Solutions Ltd | Professional & scientific | 2013 |
| Tyres 2 U (Essex) Ltd | Wholesale & retail | 2018 |
| U.K. Fabrications Ltd | Construction | 1998 |
| UDP Dental Practice Limited | Health & social care | 2020 |
| Ufford & Suffolk Polo Club Ltd | Wholesale & retail | 2013 |
| UJS London Ltd | Professional & scientific | 2020 |
| UK & Europe Transport Ltd | Transport & logistics | 2016 |
| UK Admission Support Limited | Education | 2020 |
| UK Autism Foundation | Health & social care | 2008 |
| UK BUS Advisory Limited | Professional & scientific | 2024 |
| UK Coach Service Ltd | Transport & logistics | 2026 |
| UK Consultancy, Compliance and Brokerage Ltd | Professional & scientific | 2017 |
| UK Exchange Jewellers UK Ltd | Manufacturing | 2026 |
| UK FAB Property Services Limited | Administrative & support | 2003 |
| UK Linen World Limited | Manufacturing | 2024 |
| UK Rebar Ltd | Construction | 2020 |
| UK Roofing Specialist Limited | Construction | 2012 |
| UK Sealant Applicators Limited | Construction | 2022 |
| UK Ultimate Stays Ltd | Hospitality | 2025 |
| UK Universal Trading Limited | Wholesale & retail | 2026 |
| UK Wall Ties Limited | Construction | 2024 |
| Ukmediapro Ltd | Information & communication | 2023 |
| Uksem Property Ltd | Real estate | 2018 |
| Uksem Services & Maintenance Ltd | Information & communication | 2022 |
| Ullah Business Services Ltd | Information & communication | 2011 |
| Ultra Detail Ltd | Administrative & support | 2021 |
| Ultraclean Moldova Ltd | Administrative & support | 2026 |
| Ultralign Limited | Other services | 2020 |
| UM Services Ltd | Professional & scientific | 2025 |
| Umberto's Restaurant Limited | Hospitality | 2004 |
| Umuopara Community UK Ltd | Education | 2025 |
| Uncle Fab’S Ltd | Hospitality | 2025 |
| Underground Civil Engineers Limited | Construction | 2016 |
| Underground Railway Solutions Limited | Administrative & support | 2011 |
| Underrated Music Ltd | Wholesale & retail | 2017 |
| Undici London Limited | Professional & scientific | 2020 |
| Unearth Digital Marketing Ltd | Professional & scientific | 2019 |
| Unicell Cleaning Limited | Administrative & support | 2008 |
| Uniform Pleats Ltd | Wholesale & retail | 2017 |
| Union Home Improvements Ltd | Construction | 2025 |
| Unions Barber Romford Limited | Other services | 2023 |
| Unique Health Supplements Ltd | Wholesale & retail | 2019 |
| Unique Spices Ltd T/A Zarana Ltd | Hospitality | 2025 |
| Unistart London Limited | Extraterritorial | 2013 |
| Unistart Transport Services Limited | Extraterritorial | 2017 |
| Unity Business Consultants Limited | Professional & scientific | 2024 |
| Unityone Business Support Ltd | Professional & scientific | 2025 |
| Universal Crypto Ltd | Mining & quarrying | 2018 |
| Universal Healthcare Limited | Health & social care | 2010 |
| Universal Insight Ltd | Other services | 2021 |
| Universal Meta Ltd | Information & communication | 2021 |
| Universal Services UZ Limited | Construction | 2026 |
| Universal Line Ltd | Wholesale & retail | 2019 |
| Univerted Limited | Construction | 2018 |