| Sycamore Street Limited | Real estate | 2025 |
| Symbisys Ltd | Information & communication | 2023 |
| Symonds Rare Books Ltd | Wholesale & retail | 2018 |
| Synora Logistics Ltd | Transport & logistics | 2019 |
| Synthelligence Software Ltd | Information & communication | 2025 |
| Syon Homes Limited | Real estate | 2017 |
| Syon Homes Steeplands Limited | Real estate | 2021 |
| System 3 Software Limited | Information & communication | 2004 |
| System Control (UK) Limited | Other services | 1993 |
| System Sound & Light Limited | Other services | 1986 |
| System Sound (UK) Limited | Professional & scientific | 1993 |
| SZ Properties Limited | Real estate | 2015 |
| T & K Fabrics Limited | Real estate | 1989 |
| T and L Ibiza Limited | Real estate | 2023 |
| T M H Developments Limited | Professional & scientific | 2002 |
| T&M Plumbing and Heating Ltd | Construction | 2017 |
| T.B. Limited | Arts & recreation | 1984 |
| T.F. Carpets Ltd | Construction | 2002 |
| T.I.S. Group Investments Limited | Financial services | 2020 |
| T.I.S. Group Limited | Financial services | 1998 |
| T.I.S. Holdings Limited | Professional & scientific | 2007 |
| T.Safer Limited | Professional & scientific | 2003 |
| T2T Consumables Limited | Administrative & support | 2016 |
| T9 Professionals Limited | Information & communication | 2011 |
| T9 Properties Limited | Real estate | 2016 |
| TA & AA Ventures Limited | Real estate | 2022 |
| TA Colive London Ltd | Construction | 2024 |
| TA8 Ltd | Transport & logistics | 2026 |
| Tabs Footwear Ltd | Wholesale & retail | 2025 |
| Tachbrook 1 Ltd | Real estate | 2019 |
| Tahan Property Investment Limited | Real estate | 2019 |
| Talism Holding Limited | Financial services | 2025 |
| Tall Building Ltd | Real estate | 2003 |
| Tallagh Limited | Real estate | 2020 |
| Tallagh Property Services Limited | Other services | 2020 |
| Talmish Investments UK Ltd | Real estate | 2022 |
| Tamannah Limited | Hospitality | 2023 |
| Tamarind Wood Limited | Financial services | 2025 |
| Tamebrook Limited | Construction | 1994 |
| Tamils Rehabilitation Organisation Limited | Construction | 2011 |
| Tamluck Limited | Real estate | 2024 |
| Tandam Estates Limited | Real estate | 2020 |
| Tandyl Capital Ltd | Real estate | 2021 |
| Tanglewood Productions Limited | Information & communication | 2012 |
| Tanka Management Limited | Hospitality | 2006 |
| Taoist Group Limited | Construction | 2019 |
| Tapestry Sangha Ltd | Professional & scientific | 2025 |
| Tara Caplan Ltd | Health & social care | 2020 |
| Tara Transport Ltd | Transport & logistics | 2025 |
| Target Transmissions (London) Limited | Wholesale & retail | 2002 |
| Target Z100 UK Limited | Professional & scientific | 2022 |
| Tarraig Limited | Construction | 2003 |
| Tasktrak Ltd. | Administrative & support | 2025 |
| Taste of Bamyan Valley Ltd | Hospitality | 2025 |
| Tasty Tables London Ltd | Real estate | 2003 |
| Tatco Limited | Professional & scientific | 2011 |
| Tate Communications Ltd | Information & communication | 2024 |
| Tate Group (Projects) Limited | Professional & scientific | 2010 |
| Tate Rail Limited | Administrative & support | 2000 |
| Tathaastu Stanmore Ltd | Hospitality | 2026 |
| Tatva Wellness Ltd | Information & communication | 2024 |
| Tawafi Ltd | Professional & scientific | 2021 |
| Taxdoc Limited | Professional & scientific | 2025 |
| Taxmemo Limited | Professional & scientific | 2002 |
| Taylor MAC Solutions Limited | Administrative & support | 2007 |
| Taylor Silk Properties Ltd | Real estate | 2019 |
| TBD Investments Ltd | Construction | 2024 |
| TCD Construct Ltd | Construction | 2018 |
| TCM Healthcare Limited | Health & social care | 1998 |
| TD Consulting Limited | Professional & scientific | 2025 |
| TDF Investments Limited | Construction | 1983 |
| TDI Building Solutions Ltd | Construction | 2026 |
| Tea Post Limited | Hospitality | 2025 |
| TEA40 Ltd | Other services | 2023 |
| Teague & Co Limited | Administrative & support | 2020 |
| Team Gorilla Music Limited | Extraterritorial | 2014 |
| Teamdale Limited | Professional & scientific | 1999 |
| Tech in Care Limited | Information & communication | 2021 |
| Techcessories Ltd | Wholesale & retail | 2024 |
| Techgenix Innovations Limited | Information & communication | 2025 |
| Techno Sharp Solutions Ltd | Information & communication | 2015 |
| Techno TIP Solutions Limited | Information & communication | 2011 |
| Technoinfo Limited | Professional & scientific | 1999 |
| Techqube Ltd | Information & communication | 2023 |
| Techstore 99P Ltd | Wholesale & retail | 2017 |
| TEE Jewels Limited | Wholesale & retail | 2018 |
| Teeba London Limited | Wholesale & retail | 2023 |
| Teenrise Academy Ltd | Professional & scientific | 2024 |
| Teetime Productions Limited | Information & communication | 2004 |
| Teez Parts Ltd | Wholesale & retail | 2025 |
| TEG Repairs Ltd | Wholesale & retail | 2024 |
| TEJ IT Solutions Ltd | Information & communication | 2015 |
| Telemedical World Ltd | Wholesale & retail | 2013 |
| Telu Properties Ltd | Real estate | 2015 |
| Templeco 634 Limited | Households | 2004 |
| Tenjin Consultants Limited | Information & communication | 2017 |
| Tentpole Distribution Ltd | Information & communication | 2019 |
| TEP Management Services Limited | Financial services | 1962 |
| Teravo Ltd | Real estate | 2021 |
| Terence Firrell Limited | Construction | 2005 |