| Industrial Cleaning Consultants Limited | Administrative & support | 2009 |
| Industrial Controls Limited | Administrative & support | 2018 |
| Industrial Glow Limited | Wholesale & retail | 2020 |
| Industrial Rewinds Limited | Manufacturing | 2007 |
| Industrial Self Adhesives Limited | Wholesale & retail | 1972 |
| Industrial Technology International Limited | Information & communication | 1989 |
| Industrial Textile Solutions Ltd | Manufacturing | 2022 |
| Industry Automation Limited | Manufacturing | 2022 |
| Industry Pro Ltd | Wholesale & retail | 2025 |
| Ineedbroadband Limited | Information & communication | 2007 |
| Inest Living Limited | Households | 2020 |
| Infero Training Ltd | Education | 2013 |
| INFIN8 Energy Lifestyle Ltd | Administrative & support | 2026 |
| Infinite Wholesale Ltd | Wholesale & retail | 2019 |
| Infinity & Beyond Ecom Ltd | Wholesale & retail | 2026 |
| Infinity Beauty Room Ltd | Other services | 2025 |
| Infinity Care Solutions (Nottingham) Ltd | Health & social care | 2024 |
| Infinity Drilling Ltd | Construction | 2024 |
| Infinity Events Group Limited | Arts & recreation | 2021 |
| Infinity Focus Limited | Wholesale & retail | 2013 |
| Infinity FUN Events Ltd | Arts & recreation | 2026 |
| Infinity Group Investments Limited | Financial services | 2011 |
| Infinity Group Solutions Ltd | Wholesale & retail | 2021 |
| Infinity Health Group Ltd | Health & social care | 2018 |
| Infinity Highway Design Limited | Construction | 2008 |
| Infinity Homes (Midlands) Limited | Construction | 2022 |
| Infinity Outdoor Digital Limited | Extraterritorial | 2017 |
| Infinity Outdoor Limited | Professional & scientific | 2006 |
| Infinity Outdoor Media Limited | Extraterritorial | 2011 |
| Infinity Payroll Ltd | Administrative & support | 2026 |
| Infinity Plastering Limited | Construction | 2020 |
| Infinity Solar Energy Ltd | Manufacturing | 2023 |
| Infinity Switch Ltd | Professional & scientific | 2026 |
| Infinity Vapes Ltd | Manufacturing | 2023 |
| Infinityflora Ltd | Wholesale & retail | 2026 |
| Infinnity Solutions Ltd | Information & communication | 2013 |
| Infl Ltd | Information & communication | 2013 |
| Inflatable World (Leisure) Limited | Manufacturing | 1999 |
| Inflowing Ltd | Professional & scientific | 2017 |
| Infocus Solutions Limited | Extraterritorial | 2023 |
| Infofairy Ltd | Education | 2018 |
| Infohub Ltd | Information & communication | 2003 |
| Inforhousing Ltd | Professional & scientific | 2018 |
| Informed Recruitment Ltd | Information & communication | 2019 |
| Infotech Limited | Information & communication | 2019 |
| Infotech Solutions (UK) Limited | Information & communication | 1998 |
| Infra and Designs Construction UK Ltd | Construction | 2025 |
| Infrabyte Solutions Ltd | Wholesale & retail | 2026 |
| Infrastructure and Reinstatement Solutions Ltd | Construction | 2017 |
| Infrastructure Support Solutions Limited | Construction | 2007 |
| Infrax Build Ltd | Construction | 2026 |
| Ingenio Construction Ltd | Construction | 2015 |
| Ingenio Education Limited | Education | 2017 |
| Ingenious Fools Ltd | Professional & scientific | 2024 |
| Ingenious Stuff Ltd | Wholesale & retail | 2013 |
| Ingham Doherty Limited | Financial services | 2013 |
| Ingles Developments LLP | | 2017 |
| Ingles Property Management Ltd | Real estate | 2016 |
| Ingoldmells 1915 Ltd | Wholesale & retail | 2017 |
| Ingoldmells Ice Cream Ltd | Wholesale & retail | 2025 |
| Ingredients 2 Connect Limited | Hospitality | 2016 |
| INH Property Development Limited | Real estate | 2026 |
| Inhabitory Ltd | Real estate | 2024 |
| Inhouse Corporate Services Limited | Administrative & support | 2002 |
| Inhwa Ltd | Construction | 2024 |
| INI Jones Ltd | Wholesale & retail | 2023 |
| Inikea Ltd | Wholesale & retail | 2023 |
| Inishative & Co Limited | Administrative & support | 2023 |
| Init Innovations in Transportation Limited | Administrative & support | 2010 |
| Initial D Transporting Limited | Transport & logistics | 2026 |
| Initial Energy Limited | Professional & scientific | 2018 |
| Initoms Limited | Wholesale & retail | 2025 |
| Inject & Connect Ltd | Wholesale & retail | 2025 |
| Inject-A-Therm Ltd | Construction | 2025 |
| Injected Media Ltd | Information & communication | 2006 |
| Injured Claims Limited | Other services | 2019 |
| INK and Chips Limited | Manufacturing | 2022 |
| INK Fairy Limited | Other services | 2013 |
| Inkaya Prime Solutions Ltd | Wholesale & retail | 2024 |
| Inkdelible Crafts by SK Ltd | Arts & recreation | 2026 |
| Inkerman Management Ltd | Professional & scientific | 2026 |
| Inkland Limited | Wholesale & retail | 1979 |
| Inkland Tattoos and Body Pearcing Studio Ltd | Arts & recreation | 2010 |
| Inklined UK Limited | Arts & recreation | 2016 |
| Inklusive Health Consulting Limited | Education | 2024 |
| Inkomin Solutions Limited | Information & communication | 2023 |
| Inkpin Investments Ltd | Financial services | 2023 |
| Inkpin Medical Services Limited | Health & social care | 2018 |
| Inkpot Communications Limited | Professional & scientific | 2010 |
| Inkweaver Ltd | Information & communication | 2025 |
| INL (Holdings) Limited | Financial services | 2021 |
| Inld Limited | Information & communication | 2019 |
| Inline Fencing Ltd | Administrative & support | 2023 |
| Inman Properties Limited | Real estate | 2006 |
| Inmotionuk Limited | Manufacturing | 2016 |
| Inna Metta Ltd | Health & social care | 2022 |
| Inneco Pro Limited | Wholesale & retail | 2022 |
| Inner City Care Limited | Other services | 2017 |
| Inner State Properties Limited | Construction | 2007 |
| Innerwise BIO Ltd | Information & communication | 2025 |