| Totain Ltd | Information & communication | 2024 |
| Total Carpet Cleaning South Ltd | Other services | 2016 |
| Total Equestrian Construction Limited | Construction | 2011 |
| Total Equestrian Limited | Extraterritorial | 2021 |
| Total Fire Compliance Limited | Construction | 2018 |
| Total GAS & Heating Solutions Limited | Construction | 2011 |
| Total Landscaping Works Ltd | Administrative & support | 2021 |
| Total Lifts Ltd | Manufacturing | 2002 |
| Total Manufacturing Limited | Manufacturing | 2018 |
| Total Marine Solutions Ltd | Manufacturing | 2021 |
| Total MFG Limited | Professional & scientific | 2026 |
| Total Power Maintenance Limited | Manufacturing | 2024 |
| Total Product Supplies Limited | Wholesale & retail | 1993 |
| Total Tax Management Limited | Professional & scientific | 2005 |
| Total Therapy Poole Ltd | Health & social care | 2015 |
| Totesbury Limited | Extraterritorial | 1977 |
| Tothemoonontuesday Ltd | Wholesale & retail | 2024 |
| Totta Composite Engineering Ltd | Manufacturing | 2021 |
| Toucan Services Limited | Professional & scientific | 2020 |
| Touch-Base Limited | Information & communication | 1987 |
| Touchagreat Services Ltd | Administrative & support | 2022 |
| Tour Pitch Limited | Information & communication | 2025 |
| Tower Supplies Limited | Wholesale & retail | 2025 |
| Tower View Construction Consultants Limited | Professional & scientific | 2016 |
| Towers Drylining Ltd. | Construction | 2008 |
| Towerview Guildford Limited | Administrative & support | 2018 |
| Towex Automotive Ltd | Wholesale & retail | 2025 |
| Towex Ltd | Transport & logistics | 2025 |
| Town Hall East Ltd | Real estate | 2025 |
| Town Hall Salford Right to Manage Company Ltd | Households | 2024 |
| Townsend Carpentry & Construction Ltd | Construction | 2022 |
| Toy Soldier Pictures Ltd | Arts & recreation | 2014 |
| Toy Testers Ltd | Arts & recreation | 2013 |
| TP (Evenlode) LLP | | 2006 |
| Tpcpainting Limited | Construction | 2026 |
| TPH Renewables Group CIC | Construction | 2025 |
| TPS Plumbing (Dorset) Ltd | Construction | 2005 |
| TPS Sailing Limited | Arts & recreation | 2018 |
| Trackman Ltd | Construction | 2011 |
| Traction Sports Limited | Professional & scientific | 2016 |
| Trad Couples Limited | Other services | 2025 |
| Trade & Business Consulting Ltd | Professional & scientific | 2019 |
| Trade & Travel Consulting Ltd | Information & communication | 2017 |
| Trade Boiler Spares Ltd | Wholesale & retail | 2010 |
| Trade Fair International Limited | Wholesale & retail | 2006 |
| Trade Finder Holdings Ltd | Information & communication | 2025 |
| Trade Price (UK) Conservatories, Windows & Doors Limited | Construction | 2001 |
| Trade Winds Property Group Ltd | Construction | 2017 |
| TRADE2WIN Limited | Information & communication | 2002 |
| Tradeline Windows Ltd | Construction | 2022 |
| Trademedica UK Ltd | Wholesale & retail | 2025 |
| Tradepod Limited | Administrative & support | 2024 |
| Tradesun Limited | Information & communication | 2020 |
| Trading Coast Limited | Financial services | 2012 |
| Trading Online Ltd | Wholesale & retail | 2018 |
| Tradingmarks Limited | Information & communication | 2000 |
| Traditional Plastering Ltd | Construction | 2011 |
| Traditional Shipwright Services Ltd | Manufacturing | 2006 |
| Traditional Touch 4 Cleaning Ltd | Administrative & support | 2024 |
| Tragor Limited | Professional & scientific | 2003 |
| Trail Treks Ltd | Manufacturing | 2023 |
| Train Hard Parkour Limited | Arts & recreation | 2014 |
| Training Pathways Limited | Education | 2024 |
| Trajectory Training Ltd | Professional & scientific | 2019 |
| Tralee Bournemouth Ltd | Construction | 2007 |
| Trance Party Ltd | Arts & recreation | 2023 |
| Tranquillity (Alton Road) Management Company Limited | Households | 2011 |
| Tranquillity RTM Company Limited | Households | 2020 |
| Tranquilspot Limited | Information & communication | 2022 |
| Trans-Mech Ltd | Transport & logistics | 2026 |
| Transcarpathian Ltd | Other services | 2013 |
| Transcend Estates Ltd | Real estate | 2019 |
| Transcontinental Sports Agency Limited | | 1977 |
| Transform Home Improvements Limited | Construction | 2007 |
| Transformative Coaching and Consulting Ltd | Professional & scientific | 2022 |
| Transforming Asset Management CIC | Real estate | 2020 |
| Transforming Business Services Limited | Administrative & support | 2021 |
| Transforming Capital Limited | Financial services | 2019 |
| Transforming Care Solutions Limited | Health & social care | 2019 |
| Transforming Developments Limited | Construction | 2019 |
| Transforming Group Limited | Financial services | 2019 |
| Transforming Housing Limited | Real estate | 2021 |
| Transforming Investments Limited | Real estate | 2019 |
| Transforming Partnerships Limited | Health & social care | 2021 |
| Transforming PLC | Construction | 2021 |
| Transforming Support (Birmingham) Ltd | Administrative & support | 2022 |
| Transforming Support (Coulsdon) Limited | Administrative & support | 2021 |
| Transforming Support (Croydon) Ltd | Administrative & support | 2023 |
| Transforming Support (Liverpool) Ltd | Administrative & support | 2022 |
| Transforming Support (Manchester) Ltd | Administrative & support | 2022 |
| Transforming Support (North London) Ltd | Administrative & support | 2023 |
| Transforming Support (Peterborough) Ltd | Administrative & support | 2025 |
| Transforming Support (South London) Ltd | Administrative & support | 2022 |
| Transforming Support (Surrey) Ltd | Administrative & support | 2022 |
| Transforming Support (Sussex) Ltd | Administrative & support | 2022 |
| Transforming Support (West Berkshire) Ltd | Administrative & support | 2023 |
| Transforming Support Ltd | Health & social care | 2021 |
| Transition Drilling Limited | Administrative & support | 2012 |
| Transliteria Polish Translations Limited | Professional & scientific | 2017 |
| Translogic Systems Limited | Manufacturing | 2001 |