| T. and S. Heating Limited | Construction | 1975 |
| T. Bailey Asset Management Limited | Financial services | 1999 |
| T. C. Morley & SON Ltd. | Wholesale & retail | 1994 |
| T. Fletcher and Sons Limited | Wholesale & retail | 2021 |
| T. Galvin Haulage Limited | Transport & logistics | 2005 |
| T. Jackson Limited | Real estate | 2026 |
| T. Wood Joinery Services Limited | Construction | 2003 |
| T.A. Electrical Limited | Construction | 2013 |
| T.A.D. Limited | Information & communication | 2000 |
| T.Ace’S Electronics Ltd | Wholesale & retail | 2025 |
| T.B.I. Trading Limited | Construction | 2013 |
| T.B.S FM Limited | Construction | 2014 |
| T.D Auto Motors Ltd | Wholesale & retail | 2026 |
| T.E.P. Adams & Company Limited | Other services | 2020 |
| T.Fraser Utilities Ltd | Professional & scientific | 2020 |
| T.H Doors & Installations Ltd | Construction | 2025 |
| T.H.E.M. Limited | Administrative & support | 1999 |
| T.J. Glazer Ltd | Manufacturing | 2026 |
| T.J. Vickers Ltd | Real estate | 1989 |
| T.K. Building Management Consultants Limited | Real estate | 1974 |
| T.L.C. Electrical Distributors Limited | Wholesale & retail | 1989 |
| T.M.S. (Analysis) Limited | Administrative & support | 1988 |
| T.N.S Resin Driveways Ltd | Construction | 2024 |
| T.S Rentals Limited | Real estate | 2022 |
| T.T.N.A Limited | Manufacturing | 2008 |
| T.W. Boorman Funeral Services Limited | Extraterritorial | 2004 |
| T.W.A. & A.S. Cundy Limited | Agriculture & fishing | 1981 |
| T12 PJ Limited | Hospitality | 2020 |
| T1D Fire Door Solutions Limited | Public administration | 2023 |
| T4W Henpicked Limited | Education | 2016 |
| T8'S Bar Limited | Hospitality | 2023 |
| T8'S Cafe Limited | Hospitality | 2023 |
| T8'S Wine Bar Limited | Hospitality | 2018 |
| TA Cullum Holdings Ltd | Financial services | 2024 |
| TA Motors Limited | Wholesale & retail | 2026 |
| TA VU Ltd | Transport & logistics | 2022 |
| Ta-Consulting.Com Ltd | Information & communication | 1999 |
| TA8 Consultants Ltd | Professional & scientific | 2026 |
| TAA Live Ltd | Arts & recreation | 2024 |
| Taaklands Limited | Real estate | 2022 |
| Taaksbury Property Ltd | Real estate | 2024 |
| TAB Property Maintenance Services Ltd | Construction | 2022 |
| Tablehaus Catering Ltd | Hospitality | 2026 |
| Tabletting Science Limited | Extraterritorial | 1992 |
| Tabp Ltd | Information & communication | 2023 |
| Tabs Bodyworks Ltd | Wholesale & retail | 2025 |
| Tabtool Limited | Extraterritorial | 1946 |
| Tachie Services Private Limited | Health & social care | 2026 |
| Tacktiller Limited | Information & communication | 2021 |
| Tact Consult Ltd | Administrative & support | 2023 |
| Tact Money Ltd | Administrative & support | 2024 |
| Tactical Edge Consultancy Ltd | Professional & scientific | 2023 |
| Taekwon-Do 303 LLP | | 2009 |
| TAF Bar Ltd | Hospitality | 2025 |
| TAF Developments Ltd | Construction | 2025 |
| Tafeen Ltd | Wholesale & retail | 2025 |
| TAG Electrical Ltd | Construction | 2024 |
| TAG Logistics Limited | Transport & logistics | 2016 |
| TAG Partnership LLP | | 2005 |
| TAG Plates UK Ltd | Manufacturing | 2012 |
| TAG Property Management Limited | Real estate | 2020 |
| TAG UK Property Investments Limited | Real estate | 2022 |
| Taget Care Ltd | Public administration | 2021 |
| Taggth Ltd | Manufacturing | 2025 |
| Tagio Market Ltd | Wholesale & retail | 2024 |
| Tags Compliance Group Limited | Professional & scientific | 2025 |
| Tags Creative Ltd | Professional & scientific | 2025 |
| Tahseen Noor Ltd | Wholesale & retail | 2025 |
| TAI YEE White Holdings Ltd | Real estate | 2017 |
| Taiki Tea Ltd | Wholesale & retail | 2017 |
| Tailor Group Ltd | Financial services | 2025 |
| Tailor One Ltd | Real estate | 2026 |
| Tailored Education and Community Consulting Service Limited | Information & communication | 2020 |
| Tailored Meds Limited | Health & social care | 2022 |
| Tailored Timberworks Ltd | Professional & scientific | 2024 |
| Tailormade Racking Limited | Wholesale & retail | 2008 |
| Tailorspace Limited | Information & communication | 2026 |
| Tailwind Digital Limited | Information & communication | 2021 |
| Tailwind Digital Services Limited | Information & communication | 2021 |
| Taiwo Timothy Oyesiji Ltd | Health & social care | 2024 |
| Taizz Holdings Limited | Extraterritorial | 2024 |
| TAJ Notts Limited | Hospitality | 2026 |
| TAJ Projects Ltd | Construction | 2026 |
| Tajima Embroidery Solutions Limited | Extraterritorial | 2017 |
| Tajima UK Limited | Extraterritorial | 2017 |
| Tajoora Ltd | Wholesale & retail | 2015 |
| Takasara Ltd | Wholesale & retail | 2021 |
| Takbeer Travel Ltd | Administrative & support | 2013 |
| Take 1 Studios Limited | Education | 2005 |
| Take a Call Flavour of Spice Ltd | Hospitality | 2018 |
| Take Flight Asset Management Limited | Other services | 2024 |
| Takeaway Litaliano Ltd | Hospitality | 2024 |
| Takeflight Digital Ltd | Information & communication | 2024 |
| Takt Project Management Services Ltd | Professional & scientific | 2025 |
| Tal&Zak Limited | Households | 2025 |
| Talana Limited | Professional & scientific | 1993 |
| Talavera Estates Asfordby Limited | Administrative & support | 2017 |
| Talavera Estates Limited | Administrative & support | 1999 |
| Talavera Holdings Limited | Financial services | 2022 |
| Talavera Properties Limited | Extraterritorial | 2009 |