| Touristech Limited | Transport & logistics | 2023 |
| Tournament Properties Limited | Real estate | 1960 |
| Town & Country Commercial Limited | Real estate | 2011 |
| Townaleen Investments Ltd | Real estate | 2019 |
| Toys Wolrd Ltd | Wholesale & retail | 2023 |
| TP Homes Investments Ltd | Real estate | 2025 |
| TPB Property Ltd | Real estate | 2021 |
| TPF Aviation Consulting Ltd | Professional & scientific | 2020 |
| TPM Shopfitting Services Ltd | Construction | 2013 |
| Tppc Ltd | Hospitality | 2016 |
| TPS Electronics Ltd | Manufacturing | 2012 |
| TR Lotus Ltd | Hospitality | 2017 |
| Trace IT UK Limited | Administrative & support | 2006 |
| Trackline Automotive Limited | Administrative & support | 2012 |
| Trade 7600 Limited | Transport & logistics | 2017 |
| Trade Auto Centre Ltd | Wholesale & retail | 2025 |
| Trade Lease Ltd | Administrative & support | 2022 |
| Trade Plate Drivers Ltd | Transport & logistics | 2019 |
| Trade SKILLS4U Ltd | Administrative & support | 2005 |
| Tradenova Logistics Limited | Wholesale & retail | 2024 |
| Tradeskills 4U Group Limited | Professional & scientific | 2017 |
| Trading Today Ltd | Wholesale & retail | 2022 |
| Train Wallet Ltd | Wholesale & retail | 2026 |
| Trainerhub Ltd | Information & communication | 2025 |
| Training With a Smile Limited | Health & social care | 2018 |
| Trans Data Management Ltd | Information & communication | 2000 |
| Transformers Complete Garden Transformations Ltd | Administrative & support | 2018 |
| Transport Signs Limited | Manufacturing | 2018 |
| Transport.Jc Ltd | Transport & logistics | 2022 |
| Transvalafrica Limited | Professional & scientific | 2010 |
| Transvalair (U.K.) Limited | Transport & logistics | 1976 |
| Transvalamerica Limited | Professional & scientific | 2010 |
| Transvalasia Limited | Professional & scientific | 2010 |
| Transvalfreight Limited | Professional & scientific | 2011 |
| Transvalocean Limited | Professional & scientific | 2008 |
| Transvalpack Limited | Professional & scientific | 2008 |
| Transvalroad Limited | Professional & scientific | 2008 |
| Trapus Ltd | Wholesale & retail | 2025 |
| Travel @ Comfort Ltd | Transport & logistics | 2018 |
| Travelspace UK Ltd | Administrative & support | 2023 |
| Travisiya Real Estate Ltd | Real estate | 2023 |
| Travisiya Recycle Ltd | Wholesale & retail | 2024 |
| Travistone Property Ltd | Construction | 2024 |
| Treasure Chest Soft Play Limited | Arts & recreation | 2008 |
| Treasure Hope Care Ltd | Health & social care | 2019 |
| Treasure Island GB CIC | Arts & recreation | 2016 |
| Treasuregold Ltd | Health & social care | 2018 |
| Tredion Group Limited | Administrative & support | 2017 |
| Treetop Printing & Design LLP | | 2011 |
| Treeview Court Residents Association Limited | Households | 1967 |
| Trego London Ltd | Wholesale & retail | 2025 |
| Tremaines Ltd | Professional & scientific | 2002 |
| Trenches ARE US Limited | Construction | 2021 |
| Tres Project Management Ltd | Construction | 2017 |
| Trevake Holdings Ltd | Financial services | 2026 |
| Trevake Redhill Ltd | Real estate | 2026 |
| Trevor Slaughter Holdings Ltd | Financial services | 2017 |
| TRF Hauleage Ltd | Wholesale & retail | 2018 |
| Triaxle Ltd | Other services | 2026 |
| Trica Transport Ltd | Transport & logistics | 2021 |
| Trident WHOLESALE6 Limited | Wholesale & retail | 2026 |
| Triflex Hydraulic and Services Limited | Wholesale & retail | 2024 |
| Trinity House Property Management Limited | Households | 2024 |
| Trio Property Ltd | Real estate | 2022 |
| Triple Barrier Fire Solutions Ltd | Financial services | 2025 |
| Triple M Property Development Limited | Manufacturing | 2024 |
| Triple-A-Services (UK) Limited | Other services | 2014 |
| Tripleessence Ltd | Other services | 2025 |
| Triplelift UK Limited | Information & communication | 2015 |
| Tristan Carpenter Ltd | Construction | 2026 |
| Tritium Technologies Limited | Transport & logistics | 2021 |
| Triventura Bidco Limited | Financial services | 2017 |
| Triventura Midco I Limited | Financial services | 2017 |
| Triventura Midco II Limited | Financial services | 2017 |
| TRK Protectors Ltd | Financial services | 2023 |
| Trlproperty Limited | Real estate | 2024 |
| Tropical Ambience Limited | Extraterritorial | 2004 |
| Tropical Event UK Ltd | Hospitality | 2023 |
| Tropical Innovation Limited | Administrative & support | 2002 |
| Truck IT Transport Limited | Transport & logistics | 2023 |
| True Ambient I Ltd | Financial services | 2026 |
| True Heating Solutions Ltd | Construction | 2025 |
| Truegaming Network Limited | Information & communication | 2011 |
| Truehold Ltd | Real estate | 2025 |
| Truemans Property Services Ltd | Construction | 2024 |
| Truestay Enterprises Limited | Real estate | 2025 |
| Trueye Limited | Professional & scientific | 2012 |
| Truly Ready Limited | Administrative & support | 2019 |
| Trupti Consulting Ltd | Professional & scientific | 2021 |
| Truscope Utility ARB Ltd | Agriculture & fishing | 2025 |
| Trusted Care Services Ltd | Administrative & support | 2026 |
| Trustedleadership Ltd | Professional & scientific | 2007 |
| Trustmark Maintenance Ltd | Administrative & support | 2024 |
| Truva Pharmaceuticals Ltd | Professional & scientific | 2025 |
| TS Respiratory & Sleep Physiology Ltd | Health & social care | 2025 |
| Tsoukkas-Javaid Investments Ltd | Real estate | 2018 |
| Tsvpro Ltd | Construction | 2026 |
| TTH Consultancy Limited | Professional & scientific | 2016 |
| TTM Distribution Ltd | Transport & logistics | 2012 |
| TU & U Ltd. | Information & communication | 2022 |