| J B Smarts Limited | Construction | 2024 |
| J Berry Holdings Ltd | Real estate | 2017 |
| J C Gill Developments Limited | Construction | 2014 |
| J C Gill Property Rentals Limited | Real estate | 2021 |
| J F Barron Limited | Professional & scientific | 2008 |
| J F S Estates Ltd | Financial services | 2015 |
| J Hoque Ltd | Construction | 2022 |
| J J Food & Wine Luton Limited | Wholesale & retail | 2018 |
| J J M Civil Engineering Ltd | Construction | 2018 |
| J K Young Limited | Hospitality | 2018 |
| J L Audio Visual Ltd | Construction | 2015 |
| J L Property Letting Limited | Real estate | 2017 |
| J LEE Properties Limited | Construction | 2019 |
| J M Ayres Flooring Ltd. | Wholesale & retail | 2010 |
| J M C 81 Property Ltd | Real estate | 2018 |
| J M Electrical LTN Ltd | Construction | 2019 |
| J M W Design Services Limited | Professional & scientific | 1996 |
| J MAL Construction Ltd | Construction | 2023 |
| J N M Enterprises Limited | Professional & scientific | 1997 |
| J P Creations Limited | Real estate | 2024 |
| J R Hardy Properties Ltd | Construction | 2014 |
| J R Sawyer Transport Ltd | Transport & logistics | 2019 |
| J S Auker & SON Limited | Transport & logistics | 2002 |
| J S Chiltern Electrical Ltd | Construction | 2015 |
| J S Motoring Group Ltd | Wholesale & retail | 2020 |
| J S Optics Ltd | Health & social care | 2017 |
| J Singh Assets Limited | Real estate | 2024 |
| J Suja Transport Ltd | Transport & logistics | 2015 |
| J V Price Limited | Administrative & support | 2003 |
| J W Supplies Ltd | Wholesale & retail | 2026 |
| J&A Training Ltd | Construction | 2020 |
| J&C Building & Maintenance Ltd | Construction | 2026 |
| J&C Drylining Limited | Construction | 2021 |
| J&D Superstore Ltd | Wholesale & retail | 2025 |
| J&F Fast Fulfilled Ltd | Wholesale & retail | 2021 |
| J&F Traders Limited | Wholesale & retail | 2022 |
| J&G Construction Ltd | Construction | 2026 |
| J&J Kalappurackal Limited | Hospitality | 2023 |
| J&J Robinson Ltd | Professional & scientific | 2023 |
| J&J’S Lettings Ltd | Real estate | 2026 |
| J&K Immigration Services Ltd | Professional & scientific | 2025 |
| J&K Mccafferty Limited | Real estate | 2021 |
| J&K Private Limited | Real estate | 2024 |
| J&L Thermal Limited | Construction | 2017 |
| J&M Chhina Limited | Construction | 2024 |
| J&M Resale Ltd | Wholesale & retail | 2025 |
| J&N Pharm Limited | Health & social care | 2014 |
| J&N Solutions Ltd | Administrative & support | 2019 |
| J&Ps Services UK Ltd | Information & communication | 2021 |
| J&R Coaching Limited | Education | 2017 |
| J&S 0203 Ltd | Real estate | 2025 |
| J&S Transport Global Ltd | Transport & logistics | 2024 |
| J&Sdatasolutions Ltd | Information & communication | 2025 |
| J&Sons Solutions Ltd | Wholesale & retail | 2024 |
| J&T Developments Services Ltd | Real estate | 2022 |
| J&T Partnerships Limited | Construction | 2015 |
| J. Connors Mobile Home Parks Ltd | Administrative & support | 2017 |
| J.C.Hickling Ltd | Construction | 2019 |
| J.E.Z Property Investments Ltd | Real estate | 2025 |
| J.F. Fennelly Groundworks Ltd | Construction | 2020 |
| J.H. Consultancy Ltd | Agriculture & fishing | 2017 |
| J.M Prestige Motors Ltd | Wholesale & retail | 2024 |
| J.R Anderson Painting & Decorating Ltd | Construction | 2019 |
| J.W. Stockwell Limited | Construction | 2008 |
| J2B Autos Ltd | Wholesale & retail | 2024 |
| J2SC Holdings Limited | Real estate | 2017 |
| JA Investment Group Ltd | Information & communication | 2014 |
| JA Law Ltd | Professional & scientific | 2017 |
| JA Law Solicitors Ltd | Professional & scientific | 2025 |
| JA North Investments Ltd | Real estate | 2020 |
| JA Ophthalmic Services Ltd | Health & social care | 2016 |
| JA Rentals Ltd | Administrative & support | 2025 |
| JA Transportation Ltd | Transport & logistics | 2025 |
| JAA Trading Ltd | Construction | 2019 |
| Jaat Transport Ltd | Transport & logistics | 2024 |
| Jaat Transportation Ltd | Transport & logistics | 2025 |
| Jabir Ltd | Wholesale & retail | 2024 |
| Jack Oliver Limited | Wholesale & retail | 2014 |
| Jack Simpson Tennis Ltd | Education | 2025 |
| Jackdaw Consulting Services Limited | Professional & scientific | 2011 |
| Jackmans Group Ltd | Real estate | 2024 |
| Jackmans Peri Peri Ltd | Hospitality | 2024 |
| Jackmens Ltd | Professional & scientific | 2025 |
| Jackoexpress Limited | Information & communication | 2019 |
| Jackson Insulation Ltd | Construction | 2017 |
| Jack’S Phone Repair Ltd | Other services | 2021 |
| Jacmilia Ltd | Administrative & support | 2026 |
| Jacob Consulting Limited | Construction | 2023 |
| Jacobs Enterprises Ltd | Administrative & support | 2018 |
| Jada Investments Limited | Professional & scientific | 2008 |
| Jade Henry Ltd | Other services | 2025 |
| Jademni Limited | Health & social care | 2026 |
| JAE Artistry Limited | Other services | 2024 |
| Jafar Chauffeurs Ltd | Transport & logistics | 2023 |
| Jaflong Indian Take Away Ltd | Hospitality | 2008 |
| JAG Heating Ltd | Construction | 2026 |
| JAG Maintenance Ltd | Construction | 2015 |
| Jagbajwa Construction Limited | Construction | 2016 |
| Jagdrive Limited | Transport & logistics | 2014 |
| Jaggedford Promotions Limited | Other services | 2002 |