| Ijka Ltd | Real estate | 2025 |
| IJY Limited | Wholesale & retail | 2019 |
| IK Oncology Ltd | Health & social care | 2025 |
| Ikara Limited | Wholesale & retail | 2025 |
| Ikervans Ltd | Transport & logistics | 2018 |
| Ikhan Consultancy Limited | Financial services | 2013 |
| Ikigai Medical Development Ltd | Professional & scientific | 2026 |
| Ikigai Technology Limited | Information & communication | 2024 |
| Ikim Ltd | Transport & logistics | 2020 |
| IKO Design Studio Ltd | Information & communication | 2019 |
| Ikon Furniture Ltd | Manufacturing | 2013 |
| Ikroh Limited | Information & communication | 2011 |
| IL Borro Tuscan Bistro Mayfair Ltd | Hospitality | 2021 |
| IL Ciobanu Limited | Transport & logistics | 2018 |
| Ilad Construction Ltd | Construction | 2025 |
| Ilet Northampton Ltd | Real estate | 2019 |
| Ilex Health Products Ltd | Health & social care | 2007 |
| ILF Utilities Ltd | Construction | 2018 |
| Ilie Drylining Limited | Construction | 2019 |
| Iline Technologies Ltd | Construction | 2012 |
| Ilioiu Trans Ltd | Other services | 2019 |
| ILK1 Ltd | Construction | 2021 |
| Illicit Skate Shop Limited | Wholesale & retail | 2018 |
| Illooma Limited | Information & communication | 2020 |
| Illumident Ltd | Health & social care | 2011 |
| Illycaffè UK Limited | Wholesale & retail | 2019 |
| Illyrian Enterprises Ltd | Wholesale & retail | 2024 |
| ILT Estates Limited | Real estate | 2024 |
| Ilumo Limited | Wholesale & retail | 2022 |
| Ily’S CUT Ltd | Other services | 2026 |
| Ilzite Briede Ltd | Wholesale & retail | 2018 |
| IM Construction Ltd | Construction | 2017 |
| IM Premium Ltd | Construction | 2023 |
| IM Property Solutions & Care Ltd | Manufacturing | 2026 |
| Imacsecurity Ltd | Professional & scientific | 2008 |
| Imad BED & Breakfast Ltd | Hospitality | 2020 |
| Image Gym Limited | Arts & recreation | 1996 |
| Imagen Property Solutions Limited | Households | 2021 |
| Imaginati Ltd | Wholesale & retail | 2003 |
| Imagination INK CIC | Education | 2024 |
| Imagine Building Services (Restorations) Ltd | Administrative & support | 2023 |
| Imagine Building Services Ltd | Real estate | 2013 |
| Imagine Group Holdings Ltd | Financial services | 2023 |
| Imagine Property Holdings Ltd | Real estate | 2023 |
| Imaging First Limited | Health & social care | 2012 |
| Imak Bakery Ltd | Manufacturing | 2026 |
| Imak Transport Ltd | Transport & logistics | 2021 |
| Imba Yedu Limited | Other services | 2017 |
| Imeva Consult Limited | Administrative & support | 2020 |
| Imex International Services Limited | Administrative & support | 1993 |
| IMH Electrical Services Limited | Construction | 2007 |
| IMI Traders Ltd | Construction | 2025 |
| Imkon Limited | Professional & scientific | 2020 |
| IMM Fiber Ltd | Information & communication | 2023 |
| Immaculate Grace and Glory Ltd | Health & social care | 2023 |
| Immar Capital Ltd | Real estate | 2021 |
| Immersive Bureau Ltd | Information & communication | 2021 |
| Immigration Advice Office Ltd | Professional & scientific | 2024 |
| Immigration and Nationality Services Limited | Administrative & support | 2010 |
| Immobiliser Direct Limited | Wholesale & retail | 2017 |
| Immortal Rose Limited | Other services | 2017 |
| Immortale Ltd | Wholesale & retail | 2025 |
| IMP Group Ltd | Wholesale & retail | 2020 |
| Impact Bridge Ltd | Administrative & support | 2024 |
| Impact Design and Build Ltd | Construction | 2026 |
| Impact Holdings (Northampton) Limited | Financial services | 2026 |
| Impact Performance Consulting Ltd | Professional & scientific | 2026 |
| Impact Recruitment Holdings Limited | Financial services | 2019 |
| Impact Recruitment Limited | Administrative & support | 2002 |
| Impactmatch Limited | Extraterritorial | 2023 |
| Impala Risk Consulting Limited | Professional & scientific | 2015 |
| Impeccable Homes Group Ltd | Real estate | 2021 |
| Imperial Bodies Limited | Arts & recreation | 2016 |
| Imperial Civil Enforcement Solutions Limited | Information & communication | 1986 |
| Imperial Consultancy Services PVT. Ltd | Information & communication | 2019 |
| Imperial DDA Ltd | Construction | 2018 |
| Imperial Mews Management Company Limited | Households | 2020 |
| Imperial RAJ Ltd | Hospitality | 2019 |
| Imperial Services Ltd | Administrative & support | 2017 |
| Imperial Style Limited | Hospitality | 2025 |
| Imperial Sylhet Ltd | Hospitality | 2024 |
| Imperial Yipin Food Ltd | Manufacturing | 2017 |
| Imperium Fire Consultancy Ltd | Professional & scientific | 2020 |
| Imperium Limited | Real estate | 2005 |
| Imperium Wheels Ltd | Wholesale & retail | 2025 |
| Import Prestige Cars Ltd | Wholesale & retail | 2026 |
| Impress Games Ltd | Wholesale & retail | 2013 |
| Impression Graphics & Installations Ltd | Administrative & support | 2016 |
| Impression Services Ltd | Health & social care | 2022 |
| Impression Services Property Ltd | Real estate | 2026 |
| Improve Projects Ltd | Information & communication | 2009 |
| Improving Lives Ltd | Other services | 2021 |
| Impulse Electrical (Bedford) Ltd | Construction | 2021 |
| Imran Balti Restaurant Ltd | Hospitality | 2024 |
| Imun Brickwork Ltd | Construction | 2025 |
| IMV Estates Ltd | Real estate | 2026 |
| Imza 12 Ltd | Hospitality | 2025 |
| IN 'N' OUT Centres (Holdings) Limited | Wholesale & retail | 2010 |
| IN 'N' OUT Centres Limited | Wholesale & retail | 2010 |
| IN 'N' OUT Centres Plus Limited | Wholesale & retail | 2018 |