| Truckerandy Training Limited | Education | 2026 |
| True Blue Centric Limited | Information & communication | 2019 |
| True Britt Developments Ltd | Real estate | 2025 |
| True Flame Heating Limited | Construction | 2008 |
| True Line Kitchens Limited | Construction | 2024 |
| TRUE2YOU Therapy Limited | Health & social care | 2024 |
| Truediamonds Ltd | Real estate | 2021 |
| Truefix Limited | Construction | 2018 |
| Trust Facilities Management Limited | Administrative & support | 2018 |
| Trust Insurance Group Services Limited | Financial services | 2008 |
| Trustedklean Cleaning Service Ltd | Administrative & support | 2026 |
| TS Ojediran Ltd | Transport & logistics | 2016 |
| Tsaleach Ltd | Health & social care | 2023 |
| Tsph Limited | Professional & scientific | 2013 |
| TSS Services Ltd | Other services | 2004 |
| TT Metaforà Ltd | Transport & logistics | 2022 |
| Ttkelectronics Ltd | Other services | 2025 |
| TTN Premier Ltd | Wholesale & retail | 2020 |
| Tube Fashion Ltd | Wholesale & retail | 2017 |
| Tucasa Host Ltd | Real estate | 2024 |
| Tulleyco Ltd | Wholesale & retail | 2026 |
| Tunbury Management Limited | Professional & scientific | 2007 |
| Tunde Software Services Ltd | Information & communication | 2025 |
| Tuneday Limited | Professional & scientific | 2018 |
| Tunshey Technologies Limited | Information & communication | 2023 |
| Turion Services Ltd | Professional & scientific | 2011 |
| Turkey Teeth UK Ltd | Health & social care | 2024 |
| Turkson's Healthcare Ltd | Health & social care | 2014 |
| Turry Limited | Real estate | 2001 |
| Tuscany Healthcare Services Limited | Health & social care | 2022 |
| Tusk Precision Ltd | Professional & scientific | 2020 |
| Tute & GUA Limited | Information & communication | 2008 |
| TV World Limited | Wholesale & retail | 2003 |
| Twells Healthcare Ltd | Administrative & support | 2022 |
| Twidirect Limited | Information & communication | 2020 |
| Twidol Recruitment Limited | Administrative & support | 2018 |
| Twin Estates Ltd | Real estate | 2024 |
| Twisted Twine Designs Limited | Manufacturing | 2015 |
| TWM Industrial Supplies Limited | Manufacturing | 2010 |
| TWM Properties Limited | Professional & scientific | 2017 |
| Two Larks Limited | Health & social care | 2025 |
| TWS Management Consulting Limited | Information & communication | 2021 |
| TXM Properties Limited | Real estate | 2024 |
| TXY Services Limited | Education | 2025 |
| Tyanne Solutions Ltd | Health & social care | 2022 |
| Tyndale Distribution Ltd | Wholesale & retail | 2020 |
| Tyrell Editions Limited | Wholesale & retail | 2018 |
| U&A (PVT) Limited | Wholesale & retail | 2022 |
| UAS Solutions Ltd | Professional & scientific | 2021 |
| Ucseleh Ltd | Public administration | 2023 |
| Udeliver & Co. Pa.X Ltd | Transport & logistics | 2025 |
| UFC Gym Old Street Limited | Arts & recreation | 2022 |
| UK Air Kent Limited | Administrative & support | 2002 |
| UK Carpentry S.E. Ltd | Construction | 2018 |
| UK Consumer Champions Limited | Professional & scientific | 2024 |
| UK DXB Limited | Real estate | 2019 |
| UK Fire Stopping Limited | Manufacturing | 2013 |
| UK Hair and Beauty School.Co.Uk Ltd | Other services | 2025 |
| UK High Level Scaffolding Ltd | Construction | 2020 |
| UK Homes and Properties Ltd | Real estate | 2012 |
| UK Hub Ltd | Manufacturing | 2026 |
| UK Import Services Limited | Transport & logistics | 2009 |
| UK Papa Carlo & Co Limited | Construction | 2023 |
| UK Parade Properties Ltd | Real estate | 2020 |
| UK Residential Properties Ltd | Construction | 2018 |
| UK Talent Solutions Limited | Information & communication | 2021 |
| UK Tax Ltd | Extraterritorial | 2008 |
| UK Trade Embroidery Ltd | Professional & scientific | 2022 |
| UK Translations Limited | Professional & scientific | 2017 |
| UK TSU Ltd | Wholesale & retail | 2026 |
| UK World Wide Transport Ltd | Manufacturing | 2024 |
| Ukcounsellinghub Ltd. | Education | 2011 |
| Ultimate Gems Property Investments Limited | Real estate | 2023 |
| Ultra Belief. Ltd | Wholesale & retail | 2020 |
| Ultra White Property Services & Restoration Ltd | Construction | 2015 |
| Undecim Triginta Ltd | Other services | 2019 |
| Underheat Pro Plumbing Ltd | Construction | 2025 |
| Uneek Care Ltd | Health & social care | 2020 |
| Uneek Housing Ltd | Health & social care | 2018 |
| Unfold Inclusion CIC | Health & social care | 2026 |
| Uni-Tech Building Management Systems Limited | Professional & scientific | 2008 |
| Unibrand Group Ltd | Manufacturing | 2021 |
| Unicorn Resolutions Ltd | Information & communication | 2022 |
| Unidesh BD Ltd | Professional & scientific | 2023 |
| Uniheart Ltd | Manufacturing | 2018 |
| Union Trading Company Ltd | Agriculture & fishing | 2023 |
| Unique Co-Operate Partners (Ucop) Ltd | Real estate | 2025 |
| Unique Heating & Plumbing Limited | Construction | 2025 |
| Unite Lift Services Limited | Construction | 2017 |
| Unlimited Networks Limited | Information & communication | 2014 |
| UP and Over Construction Ltd | Construction | 2018 |
| Uplet Investments Limited | Real estate | 2019 |
| Uplet Ltd | Real estate | 2009 |
| Upminster Pain Management & Anaesthesia Services Limited | Health & social care | 2015 |
| Upwards Care Ltd | Health & social care | 2023 |
| Urban Apex Holdings Ltd | Professional & scientific | 2025 |
| Urban Consultancy Management Ltd | Real estate | 2025 |
| Urban Cooling Holdings Limited | Real estate | 2020 |
| Urban Cooling Limited | Manufacturing | 2013 |
| Urban Cooling Solutions Ltd. | Construction | 2016 |