| JGC Limited | Professional & scientific | 2016 |
| JH Partners Ltd | Wholesale & retail | 2026 |
| JH Plumbing and Heating Ltd | Construction | 2024 |
| JH Sports and Fitness Ltd | Arts & recreation | 2019 |
| Jhanvi Global Solution Ltd | Professional & scientific | 2023 |
| Jhanvi Infotech Limited | Information & communication | 2023 |
| Jhar Enterprize Ltd | Wholesale & retail | 2025 |
| JHD Foods Ltd | Hospitality | 2024 |
| JHD Ltd | Hospitality | 2024 |
| Jhd&Co Ltd | Administrative & support | 2022 |
| Jhomebase Ltd | Construction | 2026 |
| JHT Trading Ltd | Wholesale & retail | 2025 |
| JI Birmingham Ltd | Hospitality | 2025 |
| Jiap Ltd | Real estate | 2018 |
| JIB Real Estate Ltd | Real estate | 2023 |
| Jiechuan Tourism & Culture Development Ltd | Wholesale & retail | 2022 |
| JIG Pattni Limited | Wholesale & retail | 2015 |
| Jig's Beauty Ltd | Other services | 2023 |
| Jimpro Ltd | Professional & scientific | 2025 |
| Jinn Ltd | Extraterritorial | 2021 |
| Jinsho Construction Ltd | Construction | 2025 |
| Jinsho Housing Ltd | Hospitality | 2025 |
| Jiprin Passion Ltd | Hospitality | 2025 |
| Jiram Properties Limited | Real estate | 2022 |
| Jisha Limited | Construction | 2025 |
| Jishal Goan Restaurant Ltd | Hospitality | 2014 |
| Jison Ltd | Wholesale & retail | 2013 |
| JJ Tokyo Sushi Ltd | Hospitality | 2025 |
| Jj&P Ltd | Administrative & support | 2020 |
| Jjjt Wealthy Limited | Real estate | 2024 |
| Jjkp UK Limited | Real estate | 2026 |
| Jjme Consultancy Services Ltd | Professional & scientific | 2019 |
| Jjopx Ltd | Financial services | 2025 |
| JJP Trades Limited | Wholesale & retail | 2024 |
| JJR Software Limited | Information & communication | 2022 |
| JK & Fast Food Ltd | Hospitality | 2020 |
| JK Aninakwa Group Ltd | Arts & recreation | 2021 |
| JK Banqueting Services Limited | Administrative & support | 2004 |
| JK Distributions Limited | Wholesale & retail | 2018 |
| JK Domestics Services Ltd | Administrative & support | 2026 |
| JK Hair and Training Limited | Other services | 2026 |
| JK London Electrical Services Ltd | Construction | 2020 |
| JK Motorbikes Limited | Wholesale & retail | 2025 |
| JK Saloon Ltd | Other services | 2023 |
| JKL Dining Ltd | Hospitality | 2025 |
| Jklr (3) LLP | | 2005 |
| Jkmk Services Ltd | Health & social care | 2024 |
| Jkmp Ventures Limited | Real estate | 2020 |
| JL Harry Ltd | Construction | 2018 |
| JLB Marketing Ltd | Professional & scientific | 2012 |
| JLK Construction Ltd | Construction | 2018 |
| JLP Interim Limited | Professional & scientific | 2021 |
| JLX Limited | Information & communication | 2010 |
| Jm&M Properties Limited | Real estate | 2022 |
| Jm&M Property Services Limited | Real estate | 2023 |
| JMC Company Ltd | Professional & scientific | 2025 |
| Jmdc Property Services Limited | Construction | 2020 |
| Jmjs Safety Solution Ltd | Manufacturing | 2015 |
| JMP Property Developments Ltd | Real estate | 2018 |
| JMS Metal Works Ltd | Construction | 2017 |
| JMT Works Ltd | Construction | 2023 |
| JMW Coffee Ltd | Hospitality | 2022 |
| JN Studio Limited | Professional & scientific | 2025 |
| JNC Capital Limited | Professional & scientific | 2018 |
| JNC Ceramics Limited | Wholesale & retail | 2003 |
| JNX PC Limited | Wholesale & retail | 2023 |
| Jobs in Adtech Ltd | Administrative & support | 2023 |
| John & LUZ Construction Ltd | Other services | 2016 |
| John Cook & Family Holdings Ltd | Real estate | 2018 |
| John Design Limited | Construction | 2019 |
| John Drylining Ltd | Construction | 2024 |
| John J Howe Plumbing Services Ltd | Construction | 2015 |
| John Lewis & SON World of Kitchens & Kitchen Makeover Store Limited | Wholesale & retail | 2000 |
| John Rafferty Ltd | Wholesale & retail | 2025 |
| John Snow Holdco Ltd | Construction | 2020 |
| John Stallion Schools Ltd | Education | 2024 |
| Johnny Johnny Ltd | Hospitality | 2025 |
| Johns Electrical 24/7 Ltd | Manufacturing | 2026 |
| Johns Paving and Drive Refurbishment Ltd | Construction | 2020 |
| Jointcater Limited | Hospitality | 1992 |
| Joker Nutrition Ltd | Hospitality | 2023 |
| Joker Autos Ltd | Wholesale & retail | 2023 |
| Jolea Property Group Limited | Real estate | 2017 |
| Jolliary Building Services Ltd | Construction | 2005 |
| JON Walsh Ltd | Information & communication | 2023 |
| Jonathan Bach and Associates Ltd | Education | 2011 |
| Jonty Industries Ltd | Wholesale & retail | 2025 |
| Jordan UK Financial Services Ltd | Financial services | 2024 |
| Jordanian Community in the UK Ltd | Health & social care | 2026 |
| Jordanian Forum in the UK | Health & social care | 2022 |
| Joseph George Associates Limited | Health & social care | 2011 |
| Joseph George Properties Ltd | Financial services | 2019 |
| Joseph London Ltd | Transport & logistics | 2025 |
| Joserra Services Ltd | Administrative & support | 2026 |
| Joshi & Sons (Holding) Ltd | Professional & scientific | 2003 |
| Joshitex UK Ltd | Wholesale & retail | 2010 |
| Joul Barber London Limited | Other services | 2025 |
| Jovenes Unidos UK Ltd | Other services | 2022 |
| Joy Sports Academy Limited | Education | 2021 |
| Joya Software House Ltd | Other services | 2017 |