| Income Rebellion Ltd | Professional & scientific | 2024 |
| Incube Consulting Ltd | Information & communication | 2022 |
| Independence Cars Ltd | Transport & logistics | 2017 |
| Independence Clubs CIC | Education | 2020 |
| Independence Project Limited | Health & social care | 1997 |
| Independent Community Heating Limited | Energy | 2005 |
| Independent Connector Services Limited | Manufacturing | 2013 |
| Independent Data Certification Ltd | Information & communication | 2023 |
| Independent Investigations (North East) Ltd | Administrative & support | 2025 |
| Independent Meters Limited | Administrative & support | 2004 |
| Independent Pipelines Limited | Energy | 1993 |
| Independent Power Networks Limited | Energy | 2003 |
| Independent Service Provider Limited | Information & communication | 2005 |
| Independent Water Networks Limited | Water & waste | 2006 |
| India and Millie Limited | Real estate | 2020 |
| Indiana (GB) Limited | Wholesale & retail | 2011 |
| Indigo Horizon Limited | Professional & scientific | 2015 |
| Indiora Limited | Wholesale & retail | 2025 |
| Individual Pathways Shropshire CIC | Education | 2025 |
| Industrial Boiler Services (UK) Ltd | Manufacturing | 2013 |
| Industrial Filtration Ltd | Manufacturing | 2023 |
| Inertia Competitions Ltd | Arts & recreation | 2026 |
| Inertiasoft Holdings Ltd | Financial services | 2016 |
| INET3 Limited | Financial services | 1992 |
| Inevitable Marketing Ltd | Education | 2024 |
| Inexus Connections Limited | Professional & scientific | 2005 |
| Inexus Group (Holdings) Limited | Professional & scientific | 2001 |
| INF Group Holdings Limited | Financial services | 2021 |
| Infantsify Ltd | Wholesale & retail | 2025 |
| Inferno Athletics Ltd | Wholesale & retail | 2026 |
| Infiniflux Ltd | Professional & scientific | 2023 |
| Infinite Edge Ltd | Financial services | 2024 |
| Infinity Dining Ltd | Hospitality | 2022 |
| Infinity PHP Limited | Real estate | 2022 |
| Infinity Real Estate London Limited | Households | 2024 |
| Infinity Supplies Limited | Wholesale & retail | 2020 |
| Infinityedge Ventures Ltd | Extraterritorial | 2024 |
| Infinix Online Ltd | Information & communication | 2024 |
| Influcate Ltd | Education | 2024 |
| Influencer Marketplace Ltd | Professional & scientific | 2025 |
| Info PAG Ltd | Administrative & support | 2026 |
| Informal Marketing Ltd. | Professional & scientific | 2023 |
| Informix Pharma Limited | Professional & scientific | 2023 |
| Infosec Technology Limited | Information & communication | 2022 |
| Infotech UK Solutions Ltd | Professional & scientific | 2025 |
| Infusia Ltd | Wholesale & retail | 2024 |
| INFUSIONS4CHEFS Ltd | Wholesale & retail | 2010 |
| Ingham Developments Limited | Construction | 2015 |
| Inglefast Limited | Wholesale & retail | 2022 |
| INK and More Ltd | Administrative & support | 2024 |
| Inkadink Ltd | Wholesale & retail | 2020 |
| Inkervate Ltd | Professional & scientific | 2026 |
| Inner LUV Ltd | Health & social care | 2022 |
| Innosip Ltd | Information & communication | 2024 |
| Innosphere Ltd | Information & communication | 2024 |
| Innostride Ltd | Information & communication | 2024 |
| Innovatius Ltd | Professional & scientific | 2023 |
| Innovative Build Hub Limited | Information & communication | 2025 |
| Innovators Global Technology Ltd | Information & communication | 2024 |
| Innovist Solutions Ltd | Information & communication | 2025 |
| Inoverx Limited | Information & communication | 2023 |
| Insert Space Ltd | Professional & scientific | 2020 |
| Inside the Wheel Ltd | Administrative & support | 2024 |
| Insideminds Consulting Ltd | Professional & scientific | 2023 |
| Insight and Outcomes Limited | Health & social care | 2026 |
| Insight Digital Limited | Professional & scientific | 2024 |
| Insight Element Ltd | Extraterritorial | 2016 |
| Insightmesh Limited | Information & communication | 2026 |
| Inspect Element Ltd | Information & communication | 2020 |
| Inspector Drain Ltd | Construction | 2023 |
| Inspire 24 Fitness Ltd | Arts & recreation | 2024 |
| Inspired Training Solutions Ltd | Education | 2020 |
| INSPIRIT360 Ltd | Information & communication | 2021 |
| Inspora Tech Ltd | Information & communication | 2025 |
| Instant Build Global Ltd | Manufacturing | 2025 |
| Instant Embroidery Ltd | Professional & scientific | 2021 |
| Instant Trend Ltd | Wholesale & retail | 2025 |
| Instantecom Ltd | Information & communication | 2024 |
| Instasoft Holdings Ltd | Extraterritorial | 2025 |
| Instructor Software Ltd | Information & communication | 2011 |
| Insur Tech Global Ltd | Information & communication | 2023 |
| Intech Developments Limited | Manufacturing | 1999 |
| Integrate AI Advisors Ltd | Information & communication | 2026 |
| Integrated Energy Consultants Ltd. | Manufacturing | 2012 |
| Integrated Energy Contractors LLP | | 2022 |
| Integrated Studies for Natural Hoof Care Practitioners Ltd | Education | 2023 |
| Integration Pathways Ltd | Extraterritorial | 2025 |
| Integritas Diversity Solutions Limited | Professional & scientific | 2010 |
| Integritas Partnership Limited | Information & communication | 2023 |
| Integritas R2R Ltd | Administrative & support | 2024 |
| Integrity Market Ltd | Wholesale & retail | 2026 |
| Integrity Tax Holdings Limited | Financial services | 2024 |
| Integrity Tax Projects Limited | Construction | 2019 |
| Integrivia Limited | Wholesale & retail | 2025 |
| Inteli AI Ltd | Wholesale & retail | 2026 |
| Intelinked Ltd | Professional & scientific | 2024 |
| Intellectio Ltd | Education | 2025 |
| Intelligence Solutions Limited | Professional & scientific | 2012 |
| Intelligent Soaps Ltd | Manufacturing | 2023 |
| Intelligent Stage Installations Limited | Arts & recreation | 2015 |