| Jankowska Psychology Limited | Health & social care | 2023 |
| Jannat Packaging Limited | Wholesale & retail | 2026 |
| Jansys UK Ltd | Extraterritorial | 2008 |
| Janta Supermarket Ltd | Wholesale & retail | 2018 |
| Janus Construction Ltd | Construction | 2021 |
| Janus Property Maintenance Ltd | Construction | 2026 |
| JAP Commercial Ltd | Real estate | 2021 |
| JAP Holdings Limited | Financial services | 2017 |
| Japec Limited | Information & communication | 2010 |
| JAR & TP Consultancy Limited | Professional & scientific | 2025 |
| Jardan Pension & Reward Services Limited | Administrative & support | 2016 |
| Jarman Accountancy Services Limited | Professional & scientific | 2000 |
| Jarvis Productions Ltd | Other services | 2025 |
| Jarvis Solutions Company Limited | Professional & scientific | 1962 |
| JAS Boutique Ltd | Manufacturing | 2025 |
| JAS Building and Landscaping Limited | Administrative & support | 2023 |
| Jasfu Real Estate Limited | Real estate | 2026 |
| Jasmin Divine Ltd | Health & social care | 2020 |
| Jasmine Lillian Benson Ltd | Extraterritorial | 2025 |
| Jasmine Lillian Etheridge Ltd | Extraterritorial | 2024 |
| Jasmine Meadow Limited | Construction | 2015 |
| Jasmine Sophia Aesthetics Ltd | Other services | 2021 |
| Jasmine Therapy Centre Ltd | Health & social care | 2024 |
| Jasneet Trans Ltd | Administrative & support | 2017 |
| Jass and Gill LLP | | 2026 |
| Jassal Planning Services Ltd | Professional & scientific | 2024 |
| Javed Cutzz Ltd | Other services | 2025 |
| Javeria Media Ltd | Wholesale & retail | 2018 |
| Jawfish Limited | Professional & scientific | 2014 |
| Jawhar Properties Ltd | Real estate | 2019 |
| JAX International Limited | Wholesale & retail | 2022 |
| Jaxi Consulting Ltd | Construction | 2022 |
| JAY ESS Transport Ltd | Transport & logistics | 2023 |
| Jayden Heating Engineers Ltd | Construction | 2023 |
| JAYDENXPRESS247 Ltd | Transport & logistics | 2025 |
| Jaydon Express Limited | Information & communication | 2025 |
| Jaylin of Bedford Limited | Real estate | 2019 |
| Jaymor Ltd | Professional & scientific | 2025 |
| Jayne Beard Associates Limited | Real estate | 1985 |
| Jazati Ltd | Administrative & support | 2023 |
| JB & Co Logistics Ltd | Transport & logistics | 2024 |
| JB & MO Property Holdings Ltd | Financial services | 2025 |
| JB Carpentry Bedfordshire Ltd | Construction | 2021 |
| JB Change Services Limited | Professional & scientific | 2026 |
| JB Interiors LUT Ltd | Construction | 2020 |
| JB Marketing Consultancy Ltd | Other services | 2013 |
| JB of Service (Jbos) Ltd | Administrative & support | 2021 |
| JB Tanning Limited | Other services | 2005 |
| JB Utilities Services Ltd | Construction | 2025 |
| Jbfm Group Ltd | Administrative & support | 2026 |
| Jbmd London Ltd | Professional & scientific | 2021 |
| JBS Tech Ltd | Information & communication | 2007 |
| Jbuachie Company Ltd | Administrative & support | 2016 |
| JC (Bedford) Carpentry Ltd | Manufacturing | 2024 |
| JC Electrical Bedford Limited | Construction | 2023 |
| JC Gough Consultancy Ltd | Professional & scientific | 2016 |
| JC Music Ltd | Arts & recreation | 2026 |
| JC Network Solutions Limited | Information & communication | 2025 |
| JC Percussion Ltd | Arts & recreation | 2025 |
| JC Property Developments Ltd | Real estate | 2012 |
| JC24 Limited | Health & social care | 2019 |
| JCB Holdings Ltd | Financial services | 2017 |
| JCH Building Contractors Ltd | Construction | 2025 |
| JCH Heating & Plumbing Ltd | Construction | 2019 |
| JCM Tattoo Studio Limited | Arts & recreation | 2015 |
| JCQ Homes Ltd | Real estate | 2019 |
| JCQ Management Services Ltd | Professional & scientific | 2020 |
| JD Dwellings Ltd | Households | 2024 |
| JD Electrical Controls Limited | Manufacturing | 2014 |
| JD Nightlife Ltd | Other services | 2019 |
| Jdcg Ltd | Professional & scientific | 2020 |
| Jdcvia Ltd | Wholesale & retail | 2021 |
| Jdeco Contracts Limited | Real estate | 2006 |
| JDH Journalism Cartoons Limited | Information & communication | 2005 |
| JDK Property Group Limited | Real estate | 2022 |
| JDM Testing Limited | Information & communication | 2014 |
| JDS Coatings Ltd | Construction | 2023 |
| JDS Saunders Property Ltd | Real estate | 2025 |
| Jdsi Limited | Construction | 2014 |
| JE Glazing Group Ltd | Construction | 2023 |
| Jebe Holdings UK Ltd | Wholesale & retail | 2024 |
| Jecal Limited | Health & social care | 2019 |
| Jedfink Limited | Information & communication | 2014 |
| Jedich Trading Company Ltd | Administrative & support | 2022 |
| JEE Consulting Ltd | Professional & scientific | 2023 |
| Jeepaz Creepaz Music Limited | Information & communication | 2016 |
| Jeffrey Utilities Ltd | Construction | 2025 |
| Jeg&Co Limited | Construction | 2024 |
| Jeldacre Limited | Real estate | 1982 |
| Jelian Support Services Ltd | Health & social care | 2018 |
| Jellis Agricultural Engineers Ltd | Manufacturing | 2013 |
| JEM Bookkeeping Ltd | Professional & scientific | 2008 |
| JEM Connect Ltd | Extraterritorial | 2022 |
| Jember Ltd | Hospitality | 2011 |
| Jemmdx Limited | Professional & scientific | 2023 |
| Jemz Ltd | Hospitality | 2015 |
| Jena Express Ltd | Wholesale & retail | 2025 |
| Jenerise Limited | Wholesale & retail | 2024 |
| Jenkins Holdings Ltd | Professional & scientific | 2020 |
| Jenkota Limited | Professional & scientific | 1999 |