| Symington Solutions Ltd | Construction | 2025 |
| Symphony Nominees Limited | Administrative & support | 2004 |
| Symy Construction Limited | Construction | 2016 |
| Syncron IT Limited | Real estate | 2019 |
| Synectiv Holdings Limited | Information & communication | 2011 |
| Synectiv Limited | Information & communication | 1999 |
| Synergi Ventures Ltd | Administrative & support | 2020 |
| Synergos Limited | Professional & scientific | 2011 |
| Synergy Structures & Shelters Ltd | Real estate | 2025 |
| Syon Global Limited | Information & communication | 2014 |
| Syspath Ltd | Professional & scientific | 2025 |
| System Connect Ltd | Administrative & support | 2020 |
| Systronics Ltd | Information & communication | 2017 |
| SZT Limited | Hospitality | 2021 |
| T & E Decor Ltd | Construction | 2025 |
| T & G Design Limited | Other services | 2004 |
| T & M Bakers Ltd | Hospitality | 2012 |
| T & V Cuaresma-Tacbi Limited | Real estate | 2017 |
| T J Griffin Ltd | Construction | 2020 |
| T K a Style Interiors Limited | Professional & scientific | 2026 |
| T K V Limited | Professional & scientific | 2019 |
| T Lampert Ltd | Health & social care | 2025 |
| T Wells Cars Limited | Transport & logistics | 2022 |
| T&F Electrical Ltd | Construction | 2026 |
| T&N Holdings (UK) Ltd | Real estate | 2015 |
| T. Martin + Co Limited | Professional & scientific | 2004 |
| T. Mcfadden Plant Limited | Construction | 2001 |
| T.J Hairstylist Limited | Other services | 2022 |
| Tabnova Ltd | Information & communication | 2019 |
| TAD 126 Consulting Limited | Professional & scientific | 2025 |
| TAG Visual Media Ltd | Information & communication | 2023 |
| TAG Visuals Ltd | Information & communication | 2021 |
| Taguri Ltd | Other services | 2011 |
| Tagzou Limited | Wholesale & retail | 2017 |
| Taha Ahmedyar Ltd | Hospitality | 2026 |
| Taha Khalil Ltd | Wholesale & retail | 2025 |
| Taiba Welfare Foundation | Other services | 2015 |
| Tailor Solutions Limited | Real estate | 2009 |
| TAJ Sultan Ltd | Wholesale & retail | 2024 |
| Takeaway Croydon Limited | Hospitality | 2026 |
| Talent Tech Ltd | Information & communication | 2024 |
| Taleva Limited | Professional & scientific | 2024 |
| Tali Residential Limited | Real estate | 2020 |
| Talinum Limited | Professional & scientific | 2015 |
| Tallann Limited | Administrative & support | 2012 |
| Talmor Property Developments Limited | Construction | 2004 |
| TAM Grup Ltd | Wholesale & retail | 2025 |
| Tambrin Limited | Professional & scientific | 2025 |
| Tambuzi Limited | Real estate | 2013 |
| Tamil Illam Ltd | Construction | 2026 |
| Tamizi Construction Limited | Construction | 2019 |
| Tamlar Limited | Professional & scientific | 2025 |
| Tampoora Retail Ltd | Wholesale & retail | 2018 |
| Tamridge Limited | Professional & scientific | 2026 |
| TAN & Co London Ltd | Professional & scientific | 2017 |
| TAN Sales (London) Limited | Wholesale & retail | 1982 |
| TAN Sales Real Estate One Limited | Real estate | 2019 |
| Tanase Repair Ltd | Construction | 2020 |
| Tanforth Limited | Professional & scientific | 2025 |
| Tang Audio Productions Limited | Professional & scientific | 1997 |
| Tannergard Music Limited | Information & communication | 2020 |
| Tannharsh Engineering Consultancy Limited | Administrative & support | 2012 |
| TANO7 Ltd | Information & communication | 2021 |
| Tanta Lounge Ltd | Hospitality | 2019 |
| Tanush Trading Ltd | Wholesale & retail | 2023 |
| Tapasweny Limited | Wholesale & retail | 2022 |
| Tapesh Signs Ltd | Manufacturing | 2024 |
| Tapit Capital Limited | Real estate | 2022 |
| Tapton Ltd | Real estate | 2024 |
| Tara Clinic Limited | Health & social care | 2010 |
| Tara Training Limited | Education | 2025 |
| Tara-Leigh Afternoon Tea Limited | Hospitality | 2025 |
| Tarastar Silver Limited | Arts & recreation | 2020 |
| Tarci Atlantic Ltd | Wholesale & retail | 2021 |
| Target Alliance Limited | Administrative & support | 2008 |
| Target Infotech Limited | Information & communication | 2008 |
| Taritan Ltd | Construction | 2025 |
| Tarlway Limited | Professional & scientific | 2026 |
| Tarwon Limited | Professional & scientific | 2025 |
| Taryag Trading Ltd | Wholesale & retail | 2021 |
| Tasellari Construction Ltd | Construction | 2020 |
| Tasha's Lashes Ltd | Other services | 2016 |
| Tashbar of Edgware Limited | Education | 2005 |
| Tashu Investments Ltd | Real estate | 2017 |
| Task Homes Trading Ltd | Real estate | 2025 |
| Task Processing Limited | Administrative & support | 2014 |
| Task Recruitment Services Ltd | Administrative & support | 2017 |
| Taspar Limited | Professional & scientific | 2023 |
| Taste of Fish Limited | Hospitality | 2023 |
| Taste of Karachi Ltd | Hospitality | 2011 |
| Tastea Limited | Professional & scientific | 2010 |
| Tasty Pizza (Colchester) Ltd | Hospitality | 2024 |
| Taswick Limited | Professional & scientific | 2025 |
| Tathaastu Restaurant Ltd | Hospitality | 2023 |
| Tatra Rope Access Ltd | Professional & scientific | 2012 |
| Tatvayog Limited | Real estate | 2020 |
| Tawax Limited | Hospitality | 2019 |
| Taycan Ventures Ltd | Information & communication | 2024 |
| Taysha Fine Art Ltd | Wholesale & retail | 2024 |
| Tayyab & Brothers Ltd | Wholesale & retail | 2024 |