| Industrial Racking Supplies Limited | Wholesale & retail | 2009 |
| Industrial Refrigeration Services (Northern) Limited | Construction | 2006 |
| Industrial Salt Supplies Limited | Wholesale & retail | 1981 |
| Industrial Supplies (Hull) Limited | Wholesale & retail | 1974 |
| Indy 1 (UK) Limited | Manufacturing | 2025 |
| Infinics Broadband Limited | Information & communication | 2022 |
| Infinics Limited | Information & communication | 2019 |
| Infinite Finds Ltd | Wholesale & retail | 2026 |
| Infiniti Infrastructure Solutions Ltd | Construction | 2024 |
| Infiniti Test and Inspection Limited | Professional & scientific | 2013 |
| Infinity Dimensions Limited | Education | 2026 |
| Infinity Social Media Ltd | Professional & scientific | 2026 |
| Infinity VIP Barber 1 Ltd | Other services | 2024 |
| Influence Incorporated Ltd | Professional & scientific | 2018 |
| Information by Design Ltd | Information & communication | 1998 |
| Infuze Limited | Information & communication | 2006 |
| Ingenious Group Limited | Professional & scientific | 2000 |
| Ingleby Distribution Limited | Transport & logistics | 2025 |
| Ingleton Joinery & Construction Limited | Construction | 2008 |
| Ings Lane Garden and Water Garden Centre Limited | Wholesale & retail | 2001 |
| Ings Pet Store & Grooming Limited | Wholesale & retail | 2025 |
| Init Creative Limited | Information & communication | 2019 |
| Initob Limited | Wholesale & retail | 2026 |
| Inkerman Tavern Ltd | Hospitality | 2025 |
| Inkigai Arts Ltd | Information & communication | 2026 |
| Inkquirey Ltd | Information & communication | 2026 |
| Inmans Road Management Company Limited | Professional & scientific | 2002 |
| INN2BARS (UK) Limited | Transport & logistics | 2007 |
| Inna Exports and Finance Ltd | Transport & logistics | 2021 |
| Inner Athlete Coaching Limited | Other services | 2023 |
| Inner Serenity Ltd | Education | 2023 |
| Inner Style Fitted Furniture Limited | Construction | 2015 |
| Innestec Limited | Information & communication | 2021 |
| INNOV8 Investments Ltd | Real estate | 2024 |
| Innova Technologies Group Limited | Information & communication | 2026 |
| INNOVATE0 Limited | Information & communication | 2020 |
| Innovation Building Products Ltd | Wholesale & retail | 2022 |
| Innovation Construction & Training Consultancy Ltd | Construction | 2017 |
| Innovation Entertainment Limited | Arts & recreation | 2019 |
| Innovation Supplies Limited | Administrative & support | 2009 |
| Innovations and More Ltd | Wholesale & retail | 2018 |
| Innovations in Care (Staffing) Ltd | Administrative & support | 2019 |
| Innovations in Care Ltd | Professional & scientific | 2018 |
| Innovations in Care Psychosocial Training Ltd | Health & social care | 2018 |
| Innovative Camper Solutions Limited | Wholesale & retail | 2016 |
| Innovative Fotography Ltd | Professional & scientific | 2025 |
| Innovator Partners Limited | Wholesale & retail | 2025 |
| Innovcare Clinical Services Limited | Health & social care | 2025 |
| Innovcare Limited | Health & social care | 2023 |
| Ino-Plaz Limited | Manufacturing | 2004 |
| Inotec Barcode Security Limited | Manufacturing | 1999 |
| Inotive Ltd | Real estate | 2025 |
| Inoventive Fire and Security Limited | Administrative & support | 2020 |
| Inpharma Ltd | Health & social care | 2013 |
| Inphase Electrical Solutions Limited | Construction | 2007 |
| Inpronet Ltd | Administrative & support | 2014 |
| Inscribe Engraving and Signs Limited | Manufacturing | 1988 |
| Insignia Signs & Engraving Ltd. | Manufacturing | 1992 |
| Inspec Systems Limited | Administrative & support | 2004 |
| Inspectionuk Ltd | Construction | 2024 |
| Inspire Communities Ltd | Education | 2010 |
| Inspire Images Dunswell Limited | Professional & scientific | 2013 |
| Inspired Drives Ltd | Construction | 2024 |
| Inspired Press Limited | Information & communication | 2020 |
| Inspired Spaces (East Yorkshire) Ltd | Construction | 2011 |
| Inspiring Better Limited | Administrative & support | 2023 |
| Inspiring Breakthrough Limited | Professional & scientific | 2003 |
| Inspiring Mums in Business Network Limited | Administrative & support | 2022 |
| Instamod Group Ltd | Professional & scientific | 2019 |
| Instamod Off-Site Solutions Limited | Manufacturing | 2023 |
| Instco Property Services Limited | Administrative & support | 2008 |
| Institch Patches Limited | Wholesale & retail | 2025 |
| Insure Assist Limited | Extraterritorial | 2020 |
| Intandem Accountancy Limited | Professional & scientific | 2012 |
| Integra Tech Limited | Information & communication | 2025 |
| Integral Utility Services Ltd | Construction | 2018 |
| Integrated Damage Solutions Limited | Professional & scientific | 2014 |
| Integrated Smart Tech Ltd | Information & communication | 2019 |
| Intelec Electrical Limited | Construction | 2016 |
| Intelligible PVT Limited | Wholesale & retail | 2023 |
| Inter Ship (U.K.) Limited | Transport & logistics | 1998 |
| Interactive Gift Voucher Limited | Arts & recreation | 2000 |
| Interactive Grottos Limited | Professional & scientific | 2019 |
| Interactive Management Group Limited | Financial services | 2022 |
| Interactive Management Services Limited | Wholesale & retail | 2023 |
| Interactive Management Solutions Limited | Wholesale & retail | 1998 |
| Intercontinental Leisure Homes Limited | Manufacturing | 2017 |
| Interdoor Limited | Manufacturing | 1985 |
| Interlab Products Limited | Manufacturing | 1987 |
| Interlex Trading Ltd | Wholesale & retail | 2024 |
| International Education Camp Ltd | Education | 2020 |
| International Flight Solutions Ltd | Administrative & support | 2013 |
| International Gro-Do Federation | Education | 2020 |
| International Store Hull Limited | Wholesale & retail | 2025 |
| International Support and Services Ltd | Professional & scientific | 2022 |
| Intertech Contracts UK Limited | Other services | 2017 |
| Intertech Holdings Limited | Financial services | 2020 |
| Intertech Media UK Limited | Professional & scientific | 1999 |
| Intimatelingeriehull Limited | Wholesale & retail | 2024 |
| Into Gear Ltd | Wholesale & retail | 2010 |