| Teamplan Cleaning Services Limited | Administrative & support | 2008 |
| Tech ARM Ltd | Information & communication | 2022 |
| Tech Tronix Centre Limited | Wholesale & retail | 2026 |
| Techbcrypto Limited | Professional & scientific | 2017 |
| Techcaree Ltd | Wholesale & retail | 2022 |
| Techcellent Ltd | Information & communication | 2021 |
| Techdrop Ltd | Information & communication | 2024 |
| Techflix Limited | Information & communication | 2019 |
| Technoviolet Works Limited | Administrative & support | 2022 |
| Technozen Ltd | Information & communication | 2025 |
| Techscheme Limited | Health & social care | 2004 |
| Techtricians Limited | Construction | 2019 |
| Tectonyx Property Company Limited | Households | 2000 |
| Tecturus Group Limited | Construction | 2018 |
| Teddington Logistics Limited | Transport & logistics | 2016 |
| Teefamm Limited | Manufacturing | 2010 |
| Tejani Consulting Ltd | Information & communication | 2025 |
| TEL Boys Ltd | Wholesale & retail | 2026 |
| Telcas Ltd | Construction | 2024 |
| Tele-Connected Limited | Information & communication | 2024 |
| Telefrag Limited | Information & communication | 2024 |
| Telemark Construction Limited | Construction | 2011 |
| Tellypro Ltd | Information & communication | 2016 |
| Temble Consultancy Ltd | Health & social care | 2023 |
| Temble Properties Ltd | Real estate | 2023 |
| Temeraire Limited | Professional & scientific | 1996 |
| Tempest Properties Limited | Professional & scientific | 1962 |
| Temple of the Moth Ltd | Other services | 2023 |
| Temple RTM Company Limited | Real estate | 2013 |
| Temple Stone Limited | Other services | 1989 |
| Temple Stone London Limited | Construction | 2010 |
| TEN Levels Ltd | Real estate | 2014 |
| Tenard Flat Management Limited | Administrative & support | 1995 |
| Tenax Limited | Construction | 2020 |
| Tenbox Electrical Ltd | Construction | 2022 |
| Teodoru IP Ltd. | Professional & scientific | 2015 |
| Terawe Technologies Limited | Information & communication | 2020 |
| Terc Holdco Limited | Financial services | 2023 |
| Terracotta Asset Management Limited | Construction | 2017 |
| Terracotta Properties Limited | Real estate | 2022 |
| Terracourt Holdings Limited | Households | 2021 |
| Territt & Sons Construction Group Ltd | Construction | 2026 |
| Terry's ALL Locks Ltd | Administrative & support | 2019 |
| Test Yantra Software Solutions Limited | Information & communication | 2014 |
| Testaccord Limited | Information & communication | 2012 |
| Testcorp Limited | Information & communication | 2009 |
| TET Tech Ltd | Information & communication | 2022 |
| Tetcad Flat Management Company Limited | Real estate | 1978 |
| Tetragene Bioit and Consulting Limited | Information & communication | 2023 |
| TEW Square Ltd. | Extraterritorial | 2016 |
| TF Atelier Group Limited | Administrative & support | 2025 |
| TF Property Consultancy Ltd | Professional & scientific | 2024 |
| TFN Tech Limited | Wholesale & retail | 2025 |
| TGL Property Services Ltd | Administrative & support | 2025 |
| TGS Group Holdings Ltd | Financial services | 2022 |
| TGS Property Care Limited | Real estate | 2026 |
| Thackray Williams LLP | | 2007 |
| Thai Yoga Massage Nails and Beauty Ltd | Other services | 2020 |
| Thaji Cakes Ltd | Wholesale & retail | 2022 |
| Thamer Ltd | Real estate | 2020 |
| Thames Aegis Security Ltd | Education | 2015 |
| Thames Autos Ltd | Wholesale & retail | 2026 |
| Thames Aviation Limited | Administrative & support | 2009 |
| Thames Brand Consultants Limited | Professional & scientific | 2005 |
| Thames Gate Management Company Limited | Households | 1991 |
| Thamesco Ltd | Real estate | 2019 |
| Thanola Limited | Real estate | 2018 |
| Thany Consulting Ltd. | Professional & scientific | 2009 |
| That Chauffeur Company Limited | Transport & logistics | 2016 |
| That's Marvellous Limited | Information & communication | 2016 |
| Thatcher Builders Ltd | Construction | 2017 |
| Thatcher Property Investments Limited | Real estate | 2020 |
| THE 7 Golden Doves Ltd | Administrative & support | 2022 |
| THE ACB Bar Ltd | Hospitality | 2025 |
| THE Advice Corner - for Public Sector Workers Ltd | Health & social care | 2025 |
| THE Agenc Ltd. | Wholesale & retail | 2011 |
| THE Andes Hockey Project CIC | Arts & recreation | 2025 |
| THE Anim Attic Ltd | Information & communication | 2025 |
| THE Apostles RTM Company Limited | Households | 2017 |
| THE Apostolic Faith Mission International (Gilgal) | Other services | 2008 |
| THE Arise Project Ltd | Manufacturing | 2024 |
| THE ARK Mission at Trinity Limited | Other services | 2021 |
| THE Atarah Group Ltd | Real estate | 2025 |
| THE Athlete Media Group Ltd | Professional & scientific | 2019 |
| THE Atrium (Buckhurst Hill) RTM Company Limited | Households | 2019 |
| THE Avenair Ltd | Real estate | 2023 |
| THE B2B Story Limited | Professional & scientific | 2016 |
| THE Baby Rack Limited | Wholesale & retail | 2024 |
| THE Barbers Lounge Grooming Limited | Other services | 2024 |
| THE Barn P & R Ltd | Hospitality | 2020 |
| THE Bawa's Services Limited | Administrative & support | 2025 |
| THE Beaufort Gate Management Company Limited | Real estate | 2013 |
| THE Beddington Park Flat Management Company Limited | Households | 2013 |
| THE Big Crown Ltd | Wholesale & retail | 2021 |
| THE Big Sparkle Ltd | Other services | 2018 |
| THE Bishop's Court (Bromley) Residents Company Limited | Real estate | 2001 |
| THE Black Economists Network Ltd | Other services | 2019 |
| THE Blackwell Clinic Ltd | Health & social care | 2023 |
| THE Bondwagon Limited | Administrative & support | 2016 |
| THE Boring MAN Ltd | Wholesale & retail | 2026 |