| Swiftrec Limited | Administrative & support | 2013 |
| Swindon Plaza Limited | Real estate | 2024 |
| Swiss Electrics London Ltd | Construction | 2024 |
| Swiss Gallery Ltd | Wholesale & retail | 2016 |
| Switchh Limited | Wholesale & retail | 2024 |
| Sword Constrution UK Ltd | Wholesale & retail | 2026 |
| SY Design Studio Ltd | Professional & scientific | 2022 |
| Syan Law Ltd | Professional & scientific | 2014 |
| Syed Startups Limited | Administrative & support | 2016 |
| Syeda Subrina Akhter Limited | Wholesale & retail | 2022 |
| Syient London Limited | Information & communication | 2016 |
| SYL Communications Limited | Other services | 2018 |
| Symphony Infotech Limited | Information & communication | 2015 |
| Symphony Chauffeurs Ltd | Transport & logistics | 2010 |
| Symphony Landscapes Limited | Construction | 2017 |
| Symstat Ltd | Information & communication | 2025 |
| Syna Consulting Ltd | Information & communication | 2018 |
| Syna Housing Ltd | Real estate | 2022 |
| Sync MD Ltd | Construction | 2024 |
| Synen Limited | Education | 2025 |
| Synergetic Spark PVT. Ltd | Transport & logistics | 2023 |
| Synergy Fulfilment Services Ltd | Wholesale & retail | 2023 |
| Synergy Home & Building Services Ltd | Construction | 2025 |
| Synergy Home Care Ltd | Health & social care | 2024 |
| Synergy UK Corporation Ltd | Real estate | 2022 |
| Synervest Property Sourcing Ltd | Real estate | 2025 |
| Synvora Ltd | Wholesale & retail | 2026 |
| Syon Capital Finance Ltd | Financial services | 2017 |
| Syon OFF Licence Ltd | Wholesale & retail | 2021 |
| Syon Surveyors Ltd | Professional & scientific | 2024 |
| SYS DAX Technology Ltd | Information & communication | 2021 |
| Sysiora Ltd | Information & communication | 2025 |
| Sysol Ltd | Information & communication | 2006 |
| Systematic ICT Services Limited | Information & communication | 2004 |
| SYY Builders Ltd | Construction | 2023 |
| T & J Enterprises Limited | Real estate | 2017 |
| T Build London Ltd | Construction | 2020 |
| T Cons Investments Ltd | Real estate | 2026 |
| T Constantine Associates Limited | Real estate | 2012 |
| T Gill Construction Ltd | Construction | 2023 |
| T S Kaler Construction Limited | Construction | 2014 |
| T Wells Group Ltd | Professional & scientific | 2024 |
| T&D Personal Services Ltd | Administrative & support | 2024 |
| T&K Mobile Ltd | Real estate | 2024 |
| T&S Alliance Limited | Hospitality | 2015 |
| T-Gurus Technologies Ltd | Information & communication | 2013 |
| T.W.Parker(Southgate)Limited | Extraterritorial | 1967 |
| Taas Global Ltd | Wholesale & retail | 2025 |
| Table 11 Hounslow Ltd | Hospitality | 2022 |
| Table 12 Hounslow Ltd | Hospitality | 2024 |
| Tabrez Therapy Ltd | Health & social care | 2023 |
| Tahasan Ahmed UK Ltd | Wholesale & retail | 2025 |
| Tahir Transport Ltd | Transport & logistics | 2018 |
| Tahsin Travels Limited | Administrative & support | 2018 |
| Tailwings Pet Travel Ltd | Transport & logistics | 2020 |
| Taint Ltd | Manufacturing | 2025 |
| TAJ 10 Ltd | Financial services | 2016 |
| TAJ Autos Limited | Wholesale & retail | 2013 |
| TAJ Buffet and Banqueting Ltd | Hospitality | 2024 |
| TAJ Kwick Fit Hounslow Ltd | Wholesale & retail | 2017 |
| TAJ Kwick Fit Limited | Wholesale & retail | 2008 |
| TAJ Kwick Fit London Limited | Wholesale & retail | 2021 |
| TAJ Kwick Fit Middlesex Limited | Wholesale & retail | 2026 |
| TAJ S&A Developments Ltd | Real estate | 2021 |
| Takaa TAK Catering Ltd | Hospitality | 2023 |
| Takaa TAK Ltd | Hospitality | 2016 |
| Takaa TAK Teddington Ltd | Hospitality | 2024 |
| Take OFF Aviation Limited | Transport & logistics | 2017 |
| TAL Estates Ltd | Real estate | 2024 |
| Talent 360 Global Limited | Information & communication | 2021 |
| Talent Manpower Ltd | Administrative & support | 2020 |
| Talha Motors Limited | Wholesale & retail | 2012 |
| Tall Blocks Ltd. | Real estate | 2017 |
| Tamensx Energy Solutions Ltd | Manufacturing | 2026 |
| Tamer Hanen Limited | Construction | 2008 |
| Tamil Community Centre | Extraterritorial | 2007 |
| Tamil National Security Services Limited | Administrative & support | 2021 |
| Tamsons Accountants Ltd | Professional & scientific | 2024 |
| TAN Lodge Ltd | Real estate | 2019 |
| Tanchi Limited | Hospitality | 2007 |
| Tandoori Nation Ltd | Hospitality | 2025 |
| Tangerine London Ltd | Manufacturing | 2025 |
| Tango Candles Ltd | Wholesale & retail | 2025 |
| Tango Souvlakii Ltd | Hospitality | 2024 |
| Taniksh Holdings Ltd | Financial services | 2025 |
| Taniksh Ltd | Wholesale & retail | 2020 |
| Tanishka Enterprises Ltd | Hospitality | 2024 |
| Tanky's Burgers Limited | Hospitality | 2020 |
| Tanmeet Foods Ltd | Wholesale & retail | 2024 |
| Tannaan Limited | Hospitality | 2025 |
| Tapavan Ltd | Transport & logistics | 2026 |
| Taplow Villas Ltd | Real estate | 2023 |
| Taraj Limited | Real estate | 2019 |
| Taran Logistics Limited | Transport & logistics | 2020 |
| Tarang Solutions Ltd | Construction | 2016 |
| Tariq Motors Limited | Wholesale & retail | 2025 |
| Tashazeventz Limited | Wholesale & retail | 2024 |
| Tasicho Limited | Construction | 2020 |
| Tasmozah Ltd | Health & social care | 2022 |
| Taste Craft Ltd | Hospitality | 2026 |