| TM (Eastleigh) Limited | Manufacturing | 1994 |
| TM Brothers Transport Ltd | Transport & logistics | 2013 |
| TM Squared Limited | Administrative & support | 2020 |
| TMB Locksmiths Ltd | Manufacturing | 2023 |
| TMC 175 Hullbridge Road Limited | Households | 2010 |
| TMH Christian Media Limited | Professional & scientific | 2012 |
| TMH Digital Ltd | Professional & scientific | 2023 |
| TMH Media Limited | Professional & scientific | 2012 |
| TMH Outdoor Ltd | Professional & scientific | 2009 |
| TMH Residential Ltd | Real estate | 2015 |
| TMK Therapy Limited | Health & social care | 2023 |
| TMP Consultants Ltd | Professional & scientific | 2025 |
| Tmsr Associates Ltd | Administrative & support | 2019 |
| TN Milling Ltd | Manufacturing | 2024 |
| TN Summit Consulting Ltd | Public administration | 2023 |
| TND Future Limited | Professional & scientific | 2014 |
| TND Future Services Ltd | Construction | 2006 |
| TNG Lifestyle Ltd | Wholesale & retail | 2019 |
| Tnmc Mediical Devices (UK) Limited | Wholesale & retail | 2000 |
| TNS Care Limited | Health & social care | 2017 |
| Toad Hall Construction Limited | Construction | 2008 |
| Toad Hall Free Range Eggs Limited | Agriculture & fishing | 2008 |
| Toaotpo Ltd | Professional & scientific | 2021 |
| Toat Agency Limited | Professional & scientific | 2022 |
| Toby & Family Ltd | Health & social care | 2020 |
| Toby Kemp International Limited | Transport & logistics | 2024 |
| Together WE Grow Community Interest Company | Administrative & support | 2017 |
| Toggle Tools Limited | Professional & scientific | 1989 |
| Togglers Arms Ltd | Real estate | 2026 |
| Toit Ltd | Information & communication | 2025 |
| Tojom Resourcing Ltd | Health & social care | 2023 |
| Tokentower Ltd | Real estate | 2023 |
| Tollgate Court (Numbers 22 to 33) Colchester Management Company Limited | Households | 1990 |
| Tollgate Court Management Company Limited | Households | 1987 |
| Tollgate Partnership (Holdings) Limited | Professional & scientific | 2011 |
| Tollgate Partnership Limited | Construction | 1987 |
| Tolly Paving Limited | Construction | 2003 |
| Tolworth Properties Ltd | Real estate | 2026 |
| TOM Bunting Vineyard Management Limited | Agriculture & fishing | 2016 |
| TOM Canham Plant & Hose Limited | Manufacturing | 2007 |
| TOM Jepson Consulting Ltd | Professional & scientific | 2022 |
| TOM Oliver Motorcycles Limited | Wholesale & retail | 2022 |
| TOM Robinson Landscaping Limited | Administrative & support | 2020 |
| Tom's Food Lounge Ltd | Hospitality | 2024 |
| Tomd.Transport Limited | Transport & logistics | 2016 |
| Tomline Properties Ltd | Real estate | 2020 |
| Tomline Services Ltd | Financial services | 2016 |
| Tomo Barber's Ltd | Other services | 2023 |
| Tomsta Limited | Transport & logistics | 2017 |
| Tony Mason Services Ltd | Construction | 2014 |
| Tonys Transport Limited | Transport & logistics | 2024 |
| TOO Angry FOX Ltd | Professional & scientific | 2023 |
| Top Class Landscaping & Fencing Ltd | Administrative & support | 2019 |
| Top Dynamics Ltd | Wholesale & retail | 2026 |
| Top Indian Curry Ltd | Hospitality | 2025 |
| Top JOB Employment Agency Limited | Administrative & support | 2018 |
| Top Shelf Detailing Limited | Administrative & support | 2025 |
| Topdoc Service Limited | Health & social care | 2021 |
| Topfield Management Limited | Administrative & support | 2007 |
| Topflite Commercial Cleaning Limited | Administrative & support | 2019 |
| Topgradeautographs Ltd | Wholesale & retail | 2022 |
| Toppillar Ltd | Wholesale & retail | 2026 |
| Topson Limited | Administrative & support | 2024 |
| Topson Property Ltd | Real estate | 2025 |
| Topteach Ltd | Education | 2022 |
| Tor's Story Limited | Wholesale & retail | 2024 |
| Toran Limited | Hospitality | 2022 |
| Torch on Ltd | Construction | 2017 |
| Torque Force Limited | Manufacturing | 2025 |
| Total Access Group Ltd | Construction | 2016 |
| Total Access Scaffolding Limited | Construction | 2012 |
| Total Car Parks Ltd | Other services | 2007 |
| Total Care Cleaning Ltd | Administrative & support | 2018 |
| Total Chauffeur Service Ltd | Extraterritorial | 2013 |
| Total Gaming Essex Limited | Arts & recreation | 2023 |
| Total Information Technology Solutions Limited | Information & communication | 2015 |
| Total Knockout Limited | Manufacturing | 2003 |
| Total Repair UK Ltd | Water & waste | 2026 |
| Total Roofing Supplies Limited | Construction | 2017 |
| Total Solution (UK) Limited | Construction | 2009 |
| Total Sports Therapy Limited | Health & social care | 2012 |
| Total Tech Services Ltd | Professional & scientific | 2018 |
| Total Training Logistics Limited | Transport & logistics | 2017 |
| Total Transportation Limited | Transport & logistics | 2005 |
| Total Woodworks Limited | Administrative & support | 2017 |
| Totalairconditioning Limited | Energy | 2020 |
| Totally EPC Ltd | Professional & scientific | 2008 |
| Totalsoft IT Solutions Ltd | Information & communication | 2025 |
| Touches"Z Limited | Other services | 2018 |
| Tour Consultants Ltd | Administrative & support | 2019 |
| Tourcloud Ltd | Professional & scientific | 2012 |
| Tourcloud Xclusive Ltd | Transport & logistics | 2023 |
| Tourky Medical Ltd | Health & social care | 2025 |
| Tower Pet & Animal Feeds Ltd | Wholesale & retail | 2010 |
| Towmate Trailers Ltd | Manufacturing | 2017 |
| Town & Village Properties (Boxford) Ltd | Real estate | 2023 |
| Town & Village Properties Ltd | Real estate | 2011 |
| Town Carpets Limited | Wholesale & retail | 2019 |
| Town Wall Executor and Trustee Company Limited | Professional & scientific | 1988 |
| Towns Green Farm Ltd | Agriculture & fishing | 2018 |