| TMP Market Infrastructure Limited | Financial services | 2026 |
| TMP Public C.I.C. | Professional & scientific | 2018 |
| Tnja Limited | Health & social care | 2024 |
| Tnja Property Limited | Other services | 2024 |
| TO BE Properties Ltd | Real estate | 2019 |
| Toast HQ Ltd | Hospitality | 2021 |
| Tobabies Financial Services Limited | Professional & scientific | 2013 |
| Tobabies Investments Limited | Real estate | 2018 |
| Tobasgo Design Limited | Professional & scientific | 1978 |
| Toby Fowler Limited | Manufacturing | 2014 |
| Toby Smith Contracting Limited | Construction | 2023 |
| Tollgates Bicester Ltd | Construction | 2018 |
| TOM Battye Coaching Limited | Other services | 2010 |
| TOM Chamlet Builders Ltd | Construction | 2012 |
| Tomkinson Domiciliary Care Limited | Health & social care | 2020 |
| Tomorrow's Child (UK) Ltd | Administrative & support | 2006 |
| Tool Solutions Ltd | Wholesale & retail | 2016 |
| Top 2 Clean Ltd | Administrative & support | 2019 |
| Top Care Medical Ltd | Administrative & support | 2018 |
| Top GUM Ltd | Information & communication | 2011 |
| Top Productions Ltd | Professional & scientific | 2017 |
| Top Wash Premium Hand Car Wash and Valeting Centre Ltd | Administrative & support | 2026 |
| Topgtaxi Ltd | Transport & logistics | 2023 |
| Tormac Pumps Ltd | Manufacturing | 2023 |
| Touchtek Limited | Manufacturing | 2013 |
| TP Pubs Limited | Hospitality | 2018 |
| TP Wheeler Automotive Limited | Wholesale & retail | 2018 |
| Trabs Group Ltd | Wholesale & retail | 2025 |
| Track Record Global Limited | Professional & scientific | 2003 |
| Trackwell Health Ltd | Information & communication | 2025 |
| Trade Prices Direct Ltd | Construction | 2025 |
| Tradeli Ltd | Wholesale & retail | 2025 |
| Tradescard Ltd | Extraterritorial | 2022 |
| Transaction Manager Limited | Professional & scientific | 2021 |
| Transense Technologies PLC | Manufacturing | 1985 |
| Transform Coaching Ltd | Information & communication | 2025 |
| Translogik Limited | Manufacturing | 2013 |
| Translogik Rfid Limited | Manufacturing | 2010 |
| Travel Cars Limited | Transport & logistics | 2023 |
| Trebecca Limited | Hospitality | 2015 |
| Trekgate Limited | Real estate | 1978 |
| Trendy Refinishers Limited | Wholesale & retail | 2002 |
| Tricolour Property Investments Ltd | Real estate | 2024 |
| Tricomatic Limited | Real estate | 1986 |
| Trident Construction Ltd | Construction | 2017 |
| Tridentmedics Ltd | Professional & scientific | 2014 |
| Trimtab Investments Ltd | Real estate | 2023 |
| Trinity Living Ltd | Real estate | 2025 |
| Trinity Travel Services Ltd | Administrative & support | 2025 |
| Trish Bartley Ltd. | Health & social care | 2025 |
| Trojan Management Ltd | Information & communication | 2016 |
| Trucs Therapeutics Limited | Professional & scientific | 2019 |
| True Builders Limited | Construction | 2025 |
| True Cure Systems Limited | Manufacturing | 2013 |
| True Peak Coffee Limited | Wholesale & retail | 2025 |
| Trusted Trucking Ltd | Transport & logistics | 2023 |
| Tryonex Ltd | Information & communication | 2019 |
| TS Properties Oxfordshire Limited | Real estate | 2018 |
| TS Trend UK Ltd | Manufacturing | 2024 |
| Tsang Apso Ltd | Professional & scientific | 2023 |
| Tsfencing and Landworks Ltd | Construction | 2018 |
| TSG Commercial Cleaning Ltd | Administrative & support | 2020 |
| Tsgm Limited | Financial services | 2024 |
| TSH Professional Services Ltd | Professional & scientific | 2018 |
| TSM Co Secretarial Services Limited | Administrative & support | 1980 |
| TSR Logistics Ltd | Transport & logistics | 2014 |
| TTD Group Limited | Wholesale & retail | 2023 |
| Ttrn Limited | Transport & logistics | 2024 |
| Tugwells Property Services Ltd | Construction | 2014 |
| Turngallant Limited | Real estate | 1987 |
| Turnkey Tenancies Ltd | Real estate | 2025 |
| Tusmore Collection Limited | Manufacturing | 2020 |
| Tusmore Holdings Limited | Agriculture & fishing | 2009 |
| Tusmore Park Farms Limited | Agriculture & fishing | 1987 |
| Twin Oak Holdings Limited | Professional & scientific | 2026 |
| Two Springs Ltd | Construction | 2023 |
| Two Twins and EVA Limited | Health & social care | 2012 |
| Twyford Broadband Community Interest Company | Other services | 2016 |
| Typewriters Period and Modern Ltd | Administrative & support | 2023 |
| Tyre Sales Abingdon Limited | Wholesale & retail | 2023 |
| U R Legal Limited | Professional & scientific | 2012 |
| Uber and Beyond Ltd | Health & social care | 2021 |
| Uhtc Ltd | Wholesale & retail | 2022 |
| UK & International Trade Ltd. | Wholesale & retail | 2017 |
| UK Anica Limited | Hospitality | 2024 |
| UK Chinese Times Limited | Information & communication | 2019 |
| UK Solar Generation Limited | Professional & scientific | 2013 |
| Ukshop Limited | Wholesale & retail | 2018 |
| Ultimate Mentors Ltd | Administrative & support | 2023 |
| Ultramarathonrunning Ltd | Wholesale & retail | 2012 |
| Umbay Ltd | Professional & scientific | 2018 |
| Uncle Alex Vets Limited | Professional & scientific | 2024 |
| Under Secure Protection Limited | Administrative & support | 2015 |
| Underdog Leadership Development Ltd | Education | 2023 |
| Uni-Export Instrumentation Limited | Administrative & support | 1998 |
| Unicus Ltd | Professional & scientific | 2013 |
| Uniform Management Limited | Professional & scientific | 2004 |
| Unify Psychology Ltd | Education | 2022 |
| Unik Consulting Ltd | Professional & scientific | 2025 |
| Unipixel Camera Solutions Ltd | Information & communication | 2023 |