| Tanning 4 U Ltd | Other services | 2025 |
| Tanning Plus Ltd | Other services | 2026 |
| Tanya LEE Ltd | Wholesale & retail | 2005 |
| Taom Capital (UK) Limited | Professional & scientific | 2010 |
| Tapeli Enterprise Ltd | Real estate | 2025 |
| Tara Home Stays Ltd | Real estate | 2024 |
| Tara Homes Ltd | Real estate | 2019 |
| Tara Ltd | Real estate | 2024 |
| Taramati Space Designs Ltd | Professional & scientific | 2025 |
| Tark Consulting Limited | Professional & scientific | 2019 |
| Tarrants Timber Limited | Wholesale & retail | 1994 |
| Tashee Health Ltd | Manufacturing | 2016 |
| Task Based Training Limited | Education | 1998 |
| Tavyaan Limited | Information & communication | 2026 |
| Tax Advice Network LLP | | 2020 |
| Taxrule Limited | Professional & scientific | 1980 |
| TAY Brothers Limited | Construction | 1990 |
| Taylored London Limited | Manufacturing | 2025 |
| Taylorfield Ltd | Construction | 2012 |
| Tbc.Design | Real estate | 2024 |
| Tcfb Ltd | Arts & recreation | 2001 |
| TCH Consult Limited | Real estate | 2013 |
| Teal Property Management Limited | Real estate | 2019 |
| Team Fahey Limited | Education | 2018 |
| TEC+ Consulting Ltd | Information & communication | 2024 |
| Tech Idea Limited | Information & communication | 2012 |
| Techenable Ltd | Information & communication | 2021 |
| Techio Limited | Other services | 2013 |
| Techno Active Ltd | Information & communication | 2014 |
| Technomarch Limited | Information & communication | 2013 |
| Technos Recruitment Ltd | Administrative & support | 2016 |
| Technxt Limited | Information & communication | 2025 |
| Teclaw Construction Technology Ltd | Construction | 2023 |
| Teczie Technologies Limited | Information & communication | 2023 |
| TED TW11 Limited | Real estate | 2026 |
| Teeth Simple Limited | Health & social care | 2019 |
| Teja Developments Ltd | Real estate | 2020 |
| TEK Move Solutions Ltd | Transport & logistics | 2015 |
| Teksun Ltd | Construction | 2026 |
| Telekey Management Limited | Real estate | 1993 |
| Temfield Management Limited | Real estate | 2004 |
| Templar Business Solutions Ltd | Professional & scientific | 2005 |
| Templar Property Ltd | Real estate | 2021 |
| Templar Technologies Ltd | Information & communication | 2022 |
| Temple Comms (UK) Ltd | Information & communication | 2011 |
| Temple Pharmacy (Ealing) Limited | Wholesale & retail | 1998 |
| Tenanty Limited | Real estate | 2022 |
| Tenar Realty Ltd | Real estate | 2022 |
| Tenkū Threads Limited | Wholesale & retail | 2024 |
| Terence James Interiors Ltd | Construction | 2015 |
| Terra Patria Ltd | Professional & scientific | 2023 |
| Terra Purus Ltd | Professional & scientific | 2020 |
| Terrafirma VP Limited | Information & communication | 2024 |
| Terraflora Garden Design Ltd | Administrative & support | 2020 |
| Testing Hub Limited | Information & communication | 2014 |
| Testnet Solutions Limited | Information & communication | 2012 |
| Thai Quarters Pinner Ltd | Other services | 2023 |
| Thame Fitness Limited | Arts & recreation | 2014 |
| Thames Building Control Limited | Professional & scientific | 2009 |
| Thamesdale Roofing Limited | Construction | 2018 |
| Thanki Associates Limited | Professional & scientific | 2006 |
| Thanki Limited | Extraterritorial | 2017 |
| Tharseo Limited | Health & social care | 2012 |
| That Limited | Real estate | 2023 |
| THE Academy of Fitness Professionals Ltd | Education | 2014 |
| THE Acoustic Centre Limited | Extraterritorial | 1988 |
| THE Afrofuturist Diary Ltd | Information & communication | 2026 |
| THE AI GUY Limited | Information & communication | 2020 |
| THE Arab British Corporation Limited | Other services | 2025 |
| THE ARK Post Productions Ltd. | Information & communication | 2000 |
| THE Arti Group Limited | Administrative & support | 2025 |
| THE Arus Properties Limited | Real estate | 2020 |
| THE Aspire Smile Ltd | Health & social care | 2022 |
| THE Aviationist Ltd | Other services | 2013 |
| THE Bathroom Workshop Limited | Construction | 2015 |
| THE Black Belt Head Hunter Ltd | Extraterritorial | 2020 |
| THE British Association of Picture Libraries and Agencies | Arts & recreation | 1993 |
| THE Business Philosopher Ltd | Information & communication | 2015 |
| THE Cake Studio Private Limited | Manufacturing | 2025 |
| THE Carling Partnership Limited | Professional & scientific | 2000 |
| THE Cheebees Limited | Education | 2025 |
| THE Chocotreats Ltd | Manufacturing | 2025 |
| THE Construction Workers Guild Limited | Administrative & support | 1997 |
| THE Cultural Collective Events CIC | Arts & recreation | 2023 |
| THE Cutting Club (Kingston) Limited | Other services | 2025 |
| THE Data Company Group Limited | Information & communication | 2018 |
| THE Digital Product Collective Limited | Professional & scientific | 2024 |
| THE Diocese of Westminster Academy Trust | Education | 2012 |
| THE Divine Laser & Skin Hub Ltd | Other services | 2025 |
| THE Eden Collective Ltd | Manufacturing | 2020 |
| THE Eden Pack Ltd | Other services | 2022 |
| THE Eggfree Cake Box-South Harrow Limited | Wholesale & retail | 2016 |
| THE Eggfree Cakebox - Southgate Limited | Wholesale & retail | 2018 |
| THE Elephant Head Limited | Information & communication | 2012 |
| THE Executive Co-Sourcer Limited | Professional & scientific | 2024 |
| THE Executive Luxury Travel Club Ltd | Administrative & support | 2021 |
| THE Felpham TAP Limited | Real estate | 2017 |
| THE Fertility Coaching Company Limited | Other services | 2021 |
| THE Food Boss Limited | Hospitality | 2017 |
| THE Forresters (Eastcote) Limited | Real estate | 1990 |