| Jonnycab Limited | Transport & logistics | 2026 |
| Jonre Ltd | Transport & logistics | 2022 |
| Jordan Bros Ltd | Extraterritorial | 2021 |
| Josah Drive Limited | Administrative & support | 2025 |
| Josan Collective Ltd | Financial services | 2023 |
| Josango Limited | Administrative & support | 2023 |
| Joseph Automotive Limited | Wholesale & retail | 2025 |
| Joseph Lawrence Homes Ltd | Construction | 2025 |
| Joseph Property Agency Group Ltd | Real estate | 2020 |
| Joseph Property Lettings Ltd | Real estate | 2020 |
| Joseph Property Resi Ltd | Real estate | 2020 |
| Joseph Read Lighting Limited | Wholesale & retail | 2012 |
| Josh Cole QS Ltd | Professional & scientific | 2025 |
| Joshua C Limited | Other services | 2002 |
| Joshualukehair Ltd | Other services | 2022 |
| Josiah Holding Ltd | Financial services | 2023 |
| Josip Haydnstrasse 2 Ltd | Other services | 2018 |
| Jothaka Ltd | Real estate | 2006 |
| Jouie Ltd | Construction | 2024 |
| Jourdain Bistro Ltd | Hospitality | 2019 |
| Jovart Ltd | Transport & logistics | 2023 |
| Jove Properties Limited | Real estate | 2024 |
| Jowers Production Limited | Arts & recreation | 2020 |
| Joy IP Ltd | Hospitality | 2025 |
| JP & CL Welham Ltd | Wholesale & retail | 2017 |
| JP Capital Solutions Limited | Financial services | 2025 |
| JP Cosmo Limited | Manufacturing | 2021 |
| JP Intech Solutions Limited | Information & communication | 2016 |
| JP Metalworks Ltd | Manufacturing | 2022 |
| JPE Financial Limited | Financial services | 2019 |
| JPG Homes Limited | Real estate | 2019 |
| Jpka Property Ltd | Real estate | 2020 |
| JPL Properties LLP | | 2009 |
| Jpmg Holdings Limited | Real estate | 2017 |
| JPS Car Sales Limited | Wholesale & retail | 2003 |
| Jpxd Ltd | Information & communication | 2025 |
| JR Barbour Pharmacies Limited | Wholesale & retail | 2002 |
| JRK Drylining Limited | Construction | 2019 |
| JRL Developments & Investments Ltd | Construction | 2026 |
| JRM Recruitment Services Ltd | Administrative & support | 2025 |
| JRM Services Ltd | Transport & logistics | 2016 |
| Jrprf Shop Limited | Wholesale & retail | 2024 |
| JRT London Limited | Administrative & support | 2025 |
| JS (East Suffolk) Limited | Real estate | 2022 |
| JS Global Rentals Ltd | Real estate | 2021 |
| JS Hospitality LDN Ltd | Hospitality | 2023 |
| Jsalltrades Ltd | Construction | 2025 |
| JSC Services Ltd | Administrative & support | 2025 |
| JSC Software Limited | Information & communication | 2025 |
| JSD CAD Draught & Design Ltd | Professional & scientific | 2022 |
| JSD Transport Limited | Transport & logistics | 2021 |
| JSE Ventures Ltd | Real estate | 2026 |
| JSH2 Ltd | Financial services | 2021 |
| Jsjtlj 2017 Limited | Arts & recreation | 2010 |
| JSR Developments Ltd | Construction | 2021 |
| JSR Driver Hire Ltd | Transport & logistics | 2018 |
| JSR02 Limited | Real estate | 2020 |
| JSR27 Limited | Health & social care | 2020 |
| JSW Installations Ltd | Manufacturing | 2020 |
| JT TM Ltd | Construction | 2025 |
| JT Wealth Ltd | Financial services | 2021 |
| JT Wilding Limited | Manufacturing | 1981 |
| Jt.Huggins Ltd | Construction | 2025 |
| JTA Air Handling Services Ltd | Other services | 2019 |
| Jtml.Com Limited | Manufacturing | 1996 |
| JTS Equity Capital Ltd | Construction | 2026 |
| JTS Holding Company Limited | Financial services | 2022 |
| JTS Maintenance Ltd | Construction | 2013 |
| JTS Plumbing and GAS Ltd | Construction | 2013 |
| JTS Properties Cumbria Limited | Real estate | 2019 |
| JTS Rentals Ltd | Real estate | 2016 |
| JU Vans Ltd | Transport & logistics | 2024 |
| Jual Cloud Services Ltd | Professional & scientific | 2021 |
| Jubilee Property Solutions Limited | Real estate | 2016 |
| Jubilee Tunbridge Wells Ltd | Hospitality | 2025 |
| Jubz Private Hire Ltd | Transport & logistics | 2026 |
| Juicy Mici Ltd | Hospitality | 2025 |
| Juju Digital Ltd | Information & communication | 2011 |
| Julie Consultancy Ltd | Information & communication | 2023 |
| Julie Technologies Ltd | Information & communication | 2024 |
| Julien Design Ltd | Professional & scientific | 2021 |
| Juliette John Limited | Health & social care | 2014 |
| Julony Properties LLP | | 2021 |
| Julony Residential Properties Ltd | Real estate | 2021 |
| Juma Thobe Limited | Wholesale & retail | 2026 |
| Jump Start Holiday Clubs Limited | Arts & recreation | 2026 |
| Jungle Run Ltd | Education | 2024 |
| Junglist Movie Ltd | Information & communication | 2024 |
| Junides Ltd | Health & social care | 2024 |
| Junkers Solution Limited | Construction | 2026 |
| Jussara Design Limited | Wholesale & retail | 2026 |
| Just Fomo Ltd | Information & communication | 2025 |
| Just Kitchens and Bathrooms Limited | Construction | 2022 |
| Just Lets (East Anglia) Limited | Real estate | 2023 |
| Just-Consulting Ltd | Professional & scientific | 2021 |
| Justbin Limited | Information & communication | 2019 |
| Justeka Ltd | Wholesale & retail | 2018 |
| Justin’S Removals Ltd | Transport & logistics | 2024 |
| Juszt Capital Ltd | Real estate | 2011 |
| JV Hospitality Ltd | Hospitality | 2025 |