| Tarmay Properties Limited | Real estate | 1976 |
| TAS Online Services Ltd | Other services | 2022 |
| Tatlock Design Associates Ltd | Administrative & support | 2004 |
| Tattvam Inc Limited | Real estate | 2024 |
| Tavaroes Holdings Limited | Financial services | 2026 |
| Taxbright Ltd | Professional & scientific | 2025 |
| Taxnova Ltd | Information & communication | 2024 |
| TAY Excelsior Limited | Real estate | 2020 |
| Taylor Foster Trading Ltd | Wholesale & retail | 2023 |
| Tayyiba Beauty Limited | Wholesale & retail | 2025 |
| TBS Publications Ltd | Information & communication | 2011 |
| TBW Asset Management Limited | Real estate | 2020 |
| TCG Initiatives Ltd | Real estate | 2025 |
| TCS Automotives Ltd | Wholesale & retail | 2025 |
| TDC Limited | Administrative & support | 2009 |
| Teac Jack Ltd | Real estate | 2020 |
| Teaera Limited | Manufacturing | 2024 |
| Teak & Teal Ltd | Other services | 2022 |
| Tech House Consulting Ltd | Professional & scientific | 2025 |
| Tech Pilot Services Limited | Information & communication | 2006 |
| Tech Plumbing Ltd | Construction | 2024 |
| Tech Spinals Ltd | Information & communication | 2013 |
| Tech Tonic Ltd | Information & communication | 2025 |
| Tech-Elec (Southern) Ltd | Professional & scientific | 1998 |
| Tech-Led Science Ltd | Education | 2025 |
| TECH2USALES Ltd | Wholesale & retail | 2019 |
| Technical H20 Ltd | Professional & scientific | 2014 |
| Technologies for Space Travel Limited | Professional & scientific | 2016 |
| Techtin IT Solutions Ltd | Information & communication | 2025 |
| Techxin Limited | Information & communication | 2015 |
| Tecmach Limited | Manufacturing | 1988 |
| TED Cain Limited | Real estate | 2004 |
| TEE Shot Events Limited | Arts & recreation | 2012 |
| TEK I-Consulting Limited | Information & communication | 2023 |
| Tektrick Productions Limited | Information & communication | 2017 |
| Televidia Ltd | Information & communication | 2024 |
| Telford Engineering Limited | Professional & scientific | 2017 |
| Tellett Engineering Consultants Limited | Professional & scientific | 2008 |
| Telm Services Ltd | Information & communication | 2025 |
| Telyco Limited | Information & communication | 2010 |
| Templar Consultancy Services Limited | Professional & scientific | 2015 |
| Temple Wave Ltd | Wholesale & retail | 2023 |
| Templeton Court (ST Albans) Limited | Households | 2011 |
| Templum Medical Ltd | Wholesale & retail | 2023 |
| Tempus Strategies Ltd | Professional & scientific | 2011 |
| TEN Crowns Touring Limited | Arts & recreation | 2024 |
| TEN Teeny Toes Limited | Arts & recreation | 2017 |
| TEN X Technologies Ltd | Information & communication | 2024 |
| Tenebris Canis Ltd | Wholesale & retail | 2022 |
| Tenfold Audio Limited | Arts & recreation | 2012 |
| Tenki Limited | Wholesale & retail | 2008 |
| Tenrec Analytics Limited | Professional & scientific | 2023 |
| Tergeo Holdings Limited | Other services | 2023 |
| Terminal Jive Limited | Extraterritorial | 2022 |
| Terra Scholaris Ltd | Information & communication | 2026 |
| Terrazzo Business Solutions Limited | Agriculture & fishing | 2007 |
| Terry Dempsey Ltd | Construction | 2016 |
| TES Motors Ltd | Wholesale & retail | 2017 |
| Tesh Homecare & Recruitment Ltd | Transport & logistics | 2022 |
| Tessera Mercator Ltd | Wholesale & retail | 2025 |
| Tessitura Ltd | Arts & recreation | 2013 |
| Test Partnership Ltd | Administrative & support | 2012 |
| Tested Right Electrical Ltd | Construction | 2025 |
| Testy Limited | Health & social care | 2020 |
| Texture AI Ltd | Professional & scientific | 2017 |
| TF Consulting Ltd | Information & communication | 2012 |
| Tflc Ltd | Information & communication | 2016 |
| TG Project Solutions Ltd | Professional & scientific | 2025 |
| Thai Star Enterprise Limited | Hospitality | 2020 |
| Thaismile Media Limited | Information & communication | 2005 |
| Thames Driving School Ltd | Education | 2013 |
| Thames Short Stays Management Limited | Hospitality | 2024 |
| Thanos Renovations Ltd | Construction | 2021 |
| That Happy Place Ltd | Professional & scientific | 2020 |
| That’S Right Clothing Ltd | Wholesale & retail | 2025 |
| THC (Hitchin) Limited | Other services | 2020 |
| THE 2K Project Ltd | Real estate | 2022 |
| THE 70 Heath Road Management Company Limited | Households | 2004 |
| THE a List Styling Limited | Administrative & support | 2021 |
| THE AB Construction Group Ltd | Construction | 2021 |
| THE AD HOC Partnership Limited | Other services | 2018 |
| THE African Heritage Festival CIC | Administrative & support | 2026 |
| THE Alpaca Ranch Limited | Agriculture & fishing | 2024 |
| THE Arbuthnott Charitable Trust | Professional & scientific | 2008 |
| THE Art HUT Studio Ltd | Education | 2023 |
| THE ART2 Ltd | Wholesale & retail | 2020 |
| THE Artists' Socks Ltd | Wholesale & retail | 2016 |
| THE Association of Noise Consultants | Other services | 2004 |
| THE Barbershed Limited | Other services | 2021 |
| THE Barefoot Accountant Limited | Professional & scientific | 2015 |
| THE Big Fixture Ltd | Professional & scientific | 2007 |
| THE Bijou Bride Ltd | Other services | 2009 |
| THE Bishops Cave Limited | Wholesale & retail | 2015 |
| THE Blue Pulse Limited | Information & communication | 2025 |
| THE Bold Mindset Blueprint Ltd | Wholesale & retail | 2026 |
| THE Brand Building Business Limited | Professional & scientific | 2013 |
| THE Brand Identity Ltd | Professional & scientific | 2024 |
| THE Bread BIN (Bakers) Ltd | Manufacturing | 1986 |
| THE Brewed Canvas Limited | Manufacturing | 2024 |
| THE Built in Studio Limited | Manufacturing | 2026 |