| Inspired Gaming (Holdings) Limited | Financial services | 2004 |
| Inspired Gaming (International) Limited | Arts & recreation | 2000 |
| Inspired Gaming (Italy) Limited | Professional & scientific | 2010 |
| Inspired Gaming (UK) Limited | Manufacturing | 1998 |
| Inspired Gaming Group Limited | Professional & scientific | 2006 |
| Inspired Gaming Limited | Extraterritorial | 2000 |
| Inspired Gaming Pension Trustees Limited | Administrative & support | 1999 |
| Inter Theatre C.I.C. | Arts & recreation | 2016 |
| Interior Gifts Limited | Wholesale & retail | 2015 |
| International Occupational Hygiene Association | Other services | 2007 |
| International Pile Croppers Limited | Extraterritorial | 2020 |
| International Power and Marine Ltd | Professional & scientific | 2017 |
| Introup Ltd | Manufacturing | 2024 |
| Intuitive Property Limited | Extraterritorial | 2007 |
| IPF Invest Ltd | Real estate | 2026 |
| IPP (Aberdeen) Limited | Wholesale & retail | 2023 |
| IPP (Carbon & Alloy) Limited | Wholesale & retail | 2016 |
| IPP (Europe) Limited | Manufacturing | 2018 |
| IPP Global Holdings Limited | Professional & scientific | 2024 |
| IPP Holdings (Cyprus) Limited | Manufacturing | 2018 |
| IPP Holdings (Europe) Limited | Manufacturing | 2018 |
| IPP Plant & Equipment Leasing Limited | Manufacturing | 2018 |
| IPP Property Holdings Limited | Manufacturing | 2018 |
| IPP Scomark (Europe) Limited | Manufacturing | 2018 |
| IPP Stock Holdings Limited | Manufacturing | 2018 |
| Ipp-Leda Limited | Wholesale & retail | 2023 |
| IQ Electrical Contractors Ltd | Construction | 2019 |
| IQ Mortgage Solutions Ltd | Financial services | 2020 |
| IQS Development Ltd | Construction | 2025 |
| IRB Ultrasound Ltd | Health & social care | 2026 |
| Iregen Limited | Professional & scientific | 2021 |
| Irfan Vest Company Ltd | Transport & logistics | 2026 |
| Iron Duck Limited | Construction | 2014 |
| Ironmongery Services Limited | Wholesale & retail | 1998 |
| Irtza Associates Limited | Transport & logistics | 2024 |
| IS Logic Ltd | Information & communication | 2013 |
| ISA 24/7 Services Ltd | Administrative & support | 2018 |
| ISA Couriers Ltd | Administrative & support | 2020 |
| ISA Hand Car Wash Ltd | Wholesale & retail | 2025 |
| Isabela Trans Ltd | Transport & logistics | 2026 |
| Ischebeck Titan Limited | Construction | 1990 |
| Isoframe Exhibitions Limited | Manufacturing | 1981 |
| Isoframe Limited | Extraterritorial | 2024 |
| Istanbul Shawarma & Grill Ltd | Hospitality | 2025 |
| IT Helpdesk Burton Ltd | Information & communication | 2013 |
| IT Space Traders Limited | Wholesale & retail | 2015 |
| IT7 Audio Limited | Wholesale & retail | 2016 |
| Ital Sardo Limited | Wholesale & retail | 2015 |
| Itech DNA Ltd | Other services | 2020 |
| Izegbeoya Juliet Ejere Limited | Health & social care | 2025 |
| J & K Scaffolding (Midlands) Limited | Construction | 2013 |
| J a Chadwick Ltd | Extraterritorial | 2016 |
| J a Civils & Surfacing Ltd | Construction | 2025 |
| J Carroll Plumbing & Heating Limited | Construction | 2022 |
| J Co Accountancy Ltd | Professional & scientific | 2022 |
| J Contracts Ltd | Manufacturing | 2025 |
| J Dexter Electrical Services Ltd | Construction | 2014 |
| J Howells Heating and Plumbing Ltd | Construction | 2026 |
| J J Autobodies Ltd. | Wholesale & retail | 2000 |
| J Knight Electrical Ltd | Construction | 2026 |
| J Mills Plumbing & Heating Ltd | Construction | 2025 |
| J P and M Hambleton Limited | Agriculture & fishing | 2016 |
| J P Palmer Limited | Construction | 2019 |
| J P S Refrigeration Limited | Manufacturing | 2006 |
| J P Walker Ltd | Real estate | 2026 |
| J Rice Fabrications Ltd | Manufacturing | 2024 |
| J Richards & Co Property Services Limited | Real estate | 2022 |
| J Verni Foods Ltd | Wholesale & retail | 2022 |
| J W Scrivens and Co Limited | Professional & scientific | 2003 |
| J&R Gadek Ltd | Real estate | 2025 |
| J&T Landscaping Ltd | Professional & scientific | 2025 |
| J. T. Leavesley (Alrewas) Limited | Wholesale & retail | 1968 |
| J.A.B. Testing Centre Ltd | Wholesale & retail | 2022 |
| J.A.B. Welding Ltd | Manufacturing | 2022 |
| J.A.C. Supplies (Derby) Limited | Manufacturing | 2024 |
| J.B.E Electrical Services and Contractors Ltd | Construction | 2017 |
| J.Gouldthorp Properties Ltd | Real estate | 2025 |
| J.M.P. 2000 Limited | Manufacturing | 1999 |
| J.S.Simnett Photographers Ltd | Other services | 2023 |
| J.T. Leavesley Limited | Professional & scientific | 1950 |
| J.T.A. Diamond Ltd | Transport & logistics | 2022 |
| J2 Equipment Services Ltd | Administrative & support | 2022 |
| Jack Leason Ltd | Agriculture & fishing | 2015 |
| Jackson Software Solutions Ltd | Information & communication | 2005 |
| Jagb Holdings Ltd | Financial services | 2023 |
| Jaguar TXA Ltd | Transport & logistics | 2024 |
| James Dodds Solutions Ltd | Professional & scientific | 2013 |
| James Watson Limited | Professional & scientific | 2010 |
| Jameson Holdings Group Ltd | Wholesale & retail | 2024 |
| Jannel Cruisers Chandlery Ltd | Wholesale & retail | 2012 |
| JAS Burton Transport Limited | Transport & logistics | 2022 |
| JAS Collectives Ltd | Hospitality | 2025 |
| Jasim Transport Limited | Transport & logistics | 2019 |
| Jasmine House Burton Ltd | Health & social care | 2024 |
| Jason Mart Ltd | Wholesale & retail | 2025 |
| Jason RO & Co Limited | Financial services | 2014 |
| JAY C Designs Ltd | Extraterritorial | 2014 |
| Jayb Ltd | Health & social care | 2021 |
| Jaykay Holdings Ltd | Construction | 2025 |
| JB Bespoke Buys Ltd | Other services | 2025 |