| J S Wholesalers Limited | Wholesale & retail | 2026 |
| J Storm Fittings Limited | Construction | 2025 |
| J T Solicitors Limited | Professional & scientific | 2021 |
| J V Smith Limited | Construction | 2006 |
| J W Residents Limited | Real estate | 2001 |
| J&D Moves Ltd | Transport & logistics | 2013 |
| J&D Partners Ltd | Real estate | 2013 |
| J&H Capital Management Limited | Real estate | 2023 |
| J&J Holmes Ltd | Real estate | 2022 |
| J&J Plumbing & Heating Limited | Construction | 2024 |
| J&K Developers Ltd | Real estate | 2021 |
| J&Mm Ltd | Wholesale & retail | 2025 |
| J&R Superstore Limited | Wholesale & retail | 2024 |
| J'Marie Collective Ltd | Administrative & support | 2024 |
| J. Hartwell Developments Limited | Construction | 2002 |
| J. Heywood Limited | Agriculture & fishing | 1960 |
| J. Holding Consultancy Ltd | Administrative & support | 2023 |
| J. M. Keenan Limited | Construction | 1976 |
| J. R. Trolleys Limited | Professional & scientific | 1987 |
| J. Smith Flooring Ltd | Construction | 2017 |
| J. Smith Property Investments Ltd | Real estate | 2020 |
| J.A.E Fashion Ltd | Wholesale & retail | 2021 |
| J.A.W.S. Aquatics Limited | Wholesale & retail | 2016 |
| J.Ask Residential Limited | Real estate | 2022 |
| J.Brice Construction Ltd | Construction | 2016 |
| J.C.Brown(Stagsden)Limited | Agriculture & fishing | 1959 |
| J.E. Shayler Limited | | 1989 |
| J.E.S. Heating & Plumbing Ltd | Construction | 2013 |
| J.H.Joyce & Sons Limited | Agriculture & fishing | 1963 |
| J.Hew Property Services Ltd | Construction | 2026 |
| J.J.P. Enterprises Limited | Hospitality | 2008 |
| J.R Hayes Electrical Ltd. | Construction | 2014 |
| J.R.Smith(Transport)Limited | Transport & logistics | 1971 |
| J.Stoch Ltd | Transport & logistics | 2016 |
| J.V. Davies Consultancy Limited | Professional & scientific | 2011 |
| J.Worboys Limited | Real estate | 2022 |
| J27PROPERTY Ltd | Real estate | 2024 |
| JA Fitness Studio Limited | Other services | 2020 |
| Jaaas Properties Ltd | Real estate | 2021 |
| Jaass Ltd | Real estate | 2015 |
| JAB Boxing EC Ltd | Other services | 2018 |
| JAC Enterprise Ltd | Professional & scientific | 2022 |
| Jacek Mazecki Limited | Wholesale & retail | 2015 |
| Jacey Court Limited | Administrative & support | 1984 |
| Jack Laurence Services Ltd | Arts & recreation | 2019 |
| Jack Phillips Developments Ltd | Construction | 2022 |
| Jack Piper's Ltd | Hospitality | 2024 |
| Jack Tudor Racing Limited | Arts & recreation | 2026 |
| Jack Tyler Performance Ltd | Other services | 2021 |
| Jackanory Communications Ltd | Professional & scientific | 2015 |
| Jacket Healthcare Ltd | Health & social care | 2022 |
| Jackies Love Kitchen Limited | Hospitality | 2014 |
| Jackman Limited | Real estate | 2015 |
| Jackson & Gray Properties Limited | Real estate | 2023 |
| Jackson Bedford Limited | Construction | 2009 |
| Jackson Demolition (Bedford) Limited | Extraterritorial | 2005 |
| Jackson Demolition Limited | Extraterritorial | 2005 |
| Jackson Environmental Limited | Water & waste | 2014 |
| Jackson Holdings Limited | Professional & scientific | 2016 |
| Jackson Hose & Hydraulics Ltd | Professional & scientific | 2021 |
| Jackson Investment Bedford Limited | Financial services | 2020 |
| Jacobharris Cleaningservices Limited | Administrative & support | 2026 |
| Jacomia Limited | Real estate | 2005 |
| Jade Buddha Spa Ltd | Other services | 2024 |
| Jadeti Bathrooms Ltd | Construction | 2023 |
| Jadu Creative Limited | Arts & recreation | 2013 |
| Jadu Global Software Ltd | Information & communication | 2011 |
| Jadu Holdings Limited | Financial services | 2022 |
| Jadu Limited | Information & communication | 2003 |
| JAG K Consultancy Ltd | Professional & scientific | 2022 |
| JAG Simply Clean Ltd | Administrative & support | 2024 |
| Jagged Edge Clapham Ltd | Other services | 2024 |
| Jagly Properties Limited | Real estate | 2020 |
| Jags Place Serviced Accommodation Ltd | Real estate | 2024 |
| JAH Education Limited | Education | 2025 |
| Jaizeandhannah Limited | Real estate | 2024 |
| Jakespare Limited | Manufacturing | 2007 |
| Jalandhar Transport Ltd | Wholesale & retail | 2022 |
| Jamag Group Ltd | Financial services | 2024 |
| Jamag Logistics Ltd | Transport & logistics | 2026 |
| James Clark & SON Limited | Professional & scientific | 1899 |
| James Davies Online Coaching Limited | Education | 2026 |
| James Fitness Ltd | Arts & recreation | 2019 |
| James GUY Enterprises Limited | Arts & recreation | 2014 |
| James Lawler Financial Limited | Financial services | 2024 |
| James M Russell Ltd | Information & communication | 2023 |
| James Marlow Limited | Other services | 2020 |
| James Stokes Limited | Extraterritorial | 2005 |
| Jameson Accounting Services Limited | Professional & scientific | 2014 |
| Jamie Catlett Fabrication Limited | Construction | 2014 |
| Jamithea Limited | Information & communication | 2011 |
| Jamuna Spice Limited | Hospitality | 2025 |
| JAN GAS and Electrical Services Limited | Construction | 2023 |
| Janat Elec Ltd | Manufacturing | 2025 |
| Jane Gamiao Sole Ltd | Health & social care | 2025 |
| Jane Southern Ltd | Information & communication | 2013 |
| Jane Young Wellness Limited | Other services | 2025 |
| Janet Jepras Consulting Limited | Health & social care | 2010 |
| Jani Legal Services Ltd | Professional & scientific | 2025 |
| Janine Alli Interiors Limited | Professional & scientific | 2024 |