| Ikarovec Limited | Professional & scientific | 2018 |
| IKB Consulting Ltd | Information & communication | 2017 |
| IKE and Linda Limited | Education | 2012 |
| Ikechukwu Limited | Real estate | 2022 |
| Ikigai Motor Company Ltd | Wholesale & retail | 2025 |
| Ikos EA Limited | Professional & scientific | 2021 |
| Ilaria Weddings Ltd | Hospitality | 2024 |
| Ilevels Instant Limited | Real estate | 2022 |
| Ilex Computing Limited | Information & communication | 1989 |
| Ilexir Limited | Information & communication | 2003 |
| Iliyan IT Solution Limited | Construction | 2022 |
| Illi Consulting Ltd | Professional & scientific | 2024 |
| Illingworth Haigh Associates Limited | Professional & scientific | 2007 |
| Illumineat Ltd | Administrative & support | 2022 |
| Illumis Lights Limited | Wholesale & retail | 2012 |
| Illusions (NFK) Ltd | Other services | 2013 |
| Illusions Spa (NFK) Ltd | Other services | 2017 |
| Ilson Kebabs Limited | Hospitality | 2023 |
| Image Coffee Co Ltd | Hospitality | 2025 |
| Image Development Marketing Ltd | Professional & scientific | 2020 |
| Image Display & Graphics Ltd. | Professional & scientific | 1997 |
| Image Ideation Limited | Manufacturing | 2013 |
| Image Improvements Ltd | Construction | 2012 |
| Imagine Health and Spa Limited | Arts & recreation | 1987 |
| Imans Enterprises Ltd | Wholesale & retail | 2026 |
| IMD Services Ltd | Construction | 2016 |
| IMF Trustees 2019 Ltd | Public administration | 2019 |
| IMF Trustees Ltd | Other services | 2014 |
| Imho Limited | Financial services | 2021 |
| Imjlaw Ltd | Education | 2013 |
| IMM Holding Ltd | Real estate | 2026 |
| Immaculate Management Solutions (UK) Ltd | Administrative & support | 2011 |
| Immedia Creative Limited | Information & communication | 2006 |
| Immerse in Nature Ltd | Education | 2022 |
| Immobiliare (Europe) Ltd | Professional & scientific | 2016 |
| Immogee Limited | Information & communication | 2024 |
| Immy Productions Ltd | Information & communication | 2024 |
| Impact Associates Limited | Information & communication | 2010 |
| Impact Energy Consulting Ltd | Administrative & support | 2022 |
| Impact Making Entrepreneurs Ltd | Professional & scientific | 2020 |
| Impact Renewable Energy Limited | Construction | 2012 |
| Impact Souvenirs Limited | Manufacturing | 2020 |
| Impeccable Healthcare Services Limited | Education | 2013 |
| Imperem Ltd | Professional & scientific | 2021 |
| Imperial (EA) Limited | Administrative & support | 2023 |
| Imperial House Management Company (Norwich) Limited | Households | 2018 |
| Imperial Valeting Ltd | Administrative & support | 2017 |
| Imperial Wheels Ltd | Administrative & support | 2023 |
| Import DAO Limited | Wholesale & retail | 2017 |
| Import Export Support Ltd | Professional & scientific | 2018 |
| Import Warehouse UK Limited | Extraterritorial | 2007 |
| Importers Agencies Limited | Wholesale & retail | 2013 |
| Impresario Investments Limited | Real estate | 2015 |
| Improve Hygiene Limited | Professional & scientific | 2008 |
| Improvise Holdings Ltd | Extraterritorial | 2022 |
| IMS Plus Ltd | Information & communication | 2017 |
| IMT Apex Ltd | Financial services | 2025 |
| Imus Design Associates Limited | Professional & scientific | 2010 |
| IMW Holdings Ltd | Financial services | 2024 |
| IN a Spin Laundry Engineers Limited | Other services | 2017 |
| IN Business Computer Services Ltd | Information & communication | 2011 |
| IN Development Studios Limited | Manufacturing | 2014 |
| IN School Media Ltd | Administrative & support | 2011 |
| IN Tandem Aviation Services Ltd | Transport & logistics | 2021 |
| IN to - Care Communications Limited | Manufacturing | 2008 |
| IN Xile Ltd | Wholesale & retail | 2015 |
| In-Difference Limited | Professional & scientific | 2025 |
| In-Spec Quality Assurance Ltd | Professional & scientific | 2012 |
| In-Sync Finance Ltd | Administrative & support | 2019 |
| IN2THEFUTURE Limited | Administrative & support | 2007 |
| Inaccess Limited | Information & communication | 2012 |
| Inari Carbon Ltd | Manufacturing | 2024 |
| Inaxx Ltd | Information & communication | 2024 |
| Inayah Transport Services Ltd | Transport & logistics | 2021 |
| Inbox Self Storage Limited | Transport & logistics | 2025 |
| Inbox Self Storage Ware Limited | Transport & logistics | 2026 |
| Inceptio Consulting Limited | Other services | 2023 |
| Inceptum Energy Ltd | Real estate | 2024 |
| Inclusive Schools Trust | Education | 2017 |
| Inco-Mol Limited | Professional & scientific | 1972 |
| Incorporated Society of Organ Builders(The) | Professional & scientific | 1947 |
| Incredible Eggs East Ltd | Other services | 2019 |
| Indalo Strategy Limited | Professional & scientific | 2023 |
| Independence Matters C.I.C. | Health & social care | 2013 |
| Independence Staff Matters Limited | Health & social care | 2013 |
| Independent AGE Assessment Limited | Health & social care | 2011 |
| Independent Engineering Services Ltd | Professional & scientific | 2025 |
| Independent House Ltd | Real estate | 2022 |
| Independent Legal Advice Services Ltd | Professional & scientific | 2018 |
| Independent Mortgages and Financial Solutions Limited | Financial services | 2004 |
| Independent Property Solutions Ltd | Real estate | 2010 |
| Independent Speech & Language Therapy Services Ltd. | Health & social care | 2004 |
| Independent Taxation Solutions Limited | Professional & scientific | 2003 |
| India & Mills Limited | Wholesale & retail | 2024 |
| India Estate Ltd | Administrative & support | 2019 |
| Indian Chillies Limited | Hospitality | 2025 |
| Indian Empress Balti Limited | Hospitality | 2019 |
| Indianspoon Wroxham Limited | Hospitality | 2024 |
| Indigo Healthcare Ltd | Health & social care | 2018 |
| Indigo Illusions Limited | Information & communication | 2018 |