| Jcem (MK) Ltd | Other services | 2025 |
| JCM Europe (UK) Limited | Manufacturing | 2004 |
| Jcnek Ltd | Financial services | 2022 |
| Jcnek Properties Limited | Real estate | 2023 |
| JCP Research and Insight Solutions Ltd | Professional & scientific | 2012 |
| JCR Management Services Ltd | Professional & scientific | 2025 |
| Jcrb Investment Limited | Real estate | 2024 |
| JCS MK Plumbing & Heating Services Ltd | Construction | 2020 |
| Jcshaulage Ltd | Transport & logistics | 2025 |
| Jcsid Holdings Ltd | Financial services | 2022 |
| JCT Community Management CIC | Education | 2019 |
| JD & SV Ltd | Professional & scientific | 2020 |
| JD Apparels UK Ltd | Wholesale & retail | 2024 |
| JD Build Projects Ltd | Construction | 2019 |
| JD Construction South Ltd | Construction | 2025 |
| JD Habitats Ltd | Construction | 2023 |
| JD Lawrence Ltd | Real estate | 2024 |
| JD Luxe Services Limited | Other services | 2011 |
| JD Visual Services LLP | | 2009 |
| JDA Heating and Plumbing Ltd | Construction | 2015 |
| JDA Wealth Ltd | Financial services | 2016 |
| JDB Maintenance Ltd | Professional & scientific | 2019 |
| Jdgc Ltd | Health & social care | 2019 |
| JDH Delivery Limited | Information & communication | 2026 |
| Jdjv Ltd | Wholesale & retail | 2024 |
| JDM IT Solutions Limited | Information & communication | 2018 |
| JDN Services Ltd | Professional & scientific | 2006 |
| JDP Window and Building Services Ltd | Construction | 2026 |
| JDR Consultancy Ltd | Information & communication | 2016 |
| JDS Technology Limited | Information & communication | 2020 |
| JDS59 Limited | Wholesale & retail | 2023 |
| Jdsellerhub Limited | Wholesale & retail | 2026 |
| JDT Land and New Homes Limited | Real estate | 2015 |
| Jean Hive Ltd | Wholesale & retail | 2022 |
| Jeanius Bar Atelier UK Ltd | Wholesale & retail | 2021 |
| Jeashan (UK) Ltd | Wholesale & retail | 2018 |
| Jeba Signalling Ltd | Construction | 2025 |
| Jebu Blue Properties Ltd | Real estate | 2025 |
| Jebu Blue Properties Sourcing Ltd | Real estate | 2025 |
| Jedel Limited | Wholesale & retail | 2017 |
| Jedidiah Group Ltd | Wholesale & retail | 2016 |
| Jedny Ltd | Health & social care | 2020 |
| Jedyka Ltd | Real estate | 2025 |
| Jeem Estates Limited | Real estate | 2021 |
| Jeeqore Limited | Information & communication | 2026 |
| Jeeves Close Property Management Company Limited | Administrative & support | 1994 |
| Jeffan Consult Ltd | Professional & scientific | 2026 |
| Jefferies MK Limited | Professional & scientific | 2024 |
| Jeffrey Media Services Limited | Administrative & support | 2011 |
| Jeffrey Powell Associates Limited | Professional & scientific | 2002 |
| Jeffries Lifestyle Ltd | Wholesale & retail | 2023 |
| Jehojireh Limited | Health & social care | 2023 |
| Jeicem Investments Ltd | Real estate | 2017 |
| Jeicemar Style Ltd | Other services | 2017 |
| Jekan Limited | Construction | 2016 |
| Jekoli IT Solutions Ltd | Information & communication | 2017 |
| Jellyfish Theatre | Arts & recreation | 2021 |
| Jemade EHI Care Ltd | Health & social care | 2020 |
| Jemit Ltd | Real estate | 2023 |
| Jemko (UK) Limited | Wholesale & retail | 2025 |
| Jemma Ltd | Real estate | 2015 |
| Jemmasons Property Ltd | Real estate | 2016 |
| Jemolite Limited Limited | Health & social care | 2021 |
| Jems Solutions Limited | Professional & scientific | 2024 |
| JEN Consulting Services Limited | Administrative & support | 2026 |
| JEN Organises Things Ltd | Administrative & support | 2019 |
| Jenaro M Limited | Hospitality | 2025 |
| Jenner Accountants Limited | Professional & scientific | 2004 |
| Jenner Company Secretaries Limited | Professional & scientific | 2007 |
| Jenni Property Ltd | Real estate | 2024 |
| Jennings Court Management Company Ltd | Real estate | 2008 |
| Jennings Heating Limited | Construction | 2005 |
| Jenny Kitchen Limited | Wholesale & retail | 2025 |
| Jensen Brooks Investments Limited | Administrative & support | 2003 |
| Jenshind Limited | Health & social care | 2025 |
| Jenson Forwarding Limited | Other services | 2021 |
| Jepfore Games Ltd | Information & communication | 2024 |
| Jephen Homes Limited | Real estate | 2026 |
| Jeremedo Ltd | Health & social care | 2022 |
| Jeremy Chaston Limited | Construction | 2023 |
| Jeremy D. Stone Consultants Ltd | Professional & scientific | 1999 |
| Jericho Builders Limited | Construction | 2015 |
| Jericho Gate Limited | Health & social care | 2020 |
| JERJEME20 Limited | Health & social care | 2021 |
| Jerome Doherty Bigara Limited | Professional & scientific | 2014 |
| Jersey Road Limited | Professional & scientific | 2010 |
| JES & JAS Limited | Health & social care | 2022 |
| Jesenia Limited | Information & communication | 2017 |
| Jeshe Holdings Ltd | Real estate | 2026 |
| Jesjudy Ltd | Health & social care | 2019 |
| Jesmond IT Ltd | Professional & scientific | 2022 |
| Jessen & Co Holdings Limited | Financial services | 2023 |
| Jessen & Co Ltd | Hospitality | 1996 |
| Jessica Goodyear Design Ltd | Professional & scientific | 2023 |
| Jessica Hawkins Promotions Ltd | Professional & scientific | 2023 |
| Jessica Hill Limited | Wholesale & retail | 2024 |
| Jessie Harris London Ltd | Manufacturing | 2017 |
| Jessons Real Estate Limited | Real estate | 2025 |
| Jess’ Furry Friends Ltd | Agriculture & fishing | 2024 |
| Jestermark Ltd | Construction | 2009 |