| Imaan Foundation UK | Health & social care | 2023 |
| Imageglen Limited | Hospitality | 1994 |
| Imagewood Limited | | 1986 |
| Imaginative Establishment Ltd | Real estate | 2020 |
| Imagine and Play Limited | Manufacturing | 2007 |
| Imagipaws Ltd | Wholesale & retail | 2025 |
| Imoblockstoys Limited | Wholesale & retail | 2025 |
| Impatien Properties Limited | Real estate | 2000 |
| Imperial Autoworks Limited | Other services | 2017 |
| Imperial First Group Limited | Real estate | 2024 |
| Imperial Hub Ltd | Wholesale & retail | 2021 |
| Imperial Launderette Ltd | Other services | 2024 |
| Imperium Balloons Ltd | Other services | 2020 |
| Impetus Distribution Limited | Wholesale & retail | 1983 |
| Impetus Records Limited | Information & communication | 1982 |
| Imranify Ltd | Wholesale & retail | 2025 |
| IN Still Tree Limited | Administrative & support | 2008 |
| Inclusive Communities Limited | Education | 2008 |
| Indecon Building Limited | Construction | 1979 |
| Indeedcare Partners Limited | Health & social care | 2024 |
| Independent Property Services | | 1994 |
| Independent Therapy Solutions Limited | Arts & recreation | 2005 |
| Indepths Ltd | Administrative & support | 2006 |
| Indigenous Solutions Ltd | Wholesale & retail | 2021 |
| Indigo Abode Limited | Health & social care | 2019 |
| Individual Entrepreneur Vladislav Korolev Limited | Information & communication | 2023 |
| Indivisual Tech Ltd | Wholesale & retail | 2023 |
| Indodex Property Developments Limited | Real estate | 2003 |
| Indulge Ambition Ltd | Wholesale & retail | 2020 |
| Industrial GAS Turbine Consultancy Ltd | Professional & scientific | 2005 |
| Infinite Success Limited | Other services | 2002 |
| Infinity Mojo Ltd | Wholesale & retail | 2025 |
| Infinity Pro Limited | Professional & scientific | 2002 |
| Influential Care Ltd | Health & social care | 2024 |
| Infracomm Solutions Limited | Professional & scientific | 2007 |
| Ingatestone Translations Limited | Professional & scientific | 1999 |
| Ingcebo Holdings Ltd | Professional & scientific | 2017 |
| Ingleby Way Limited | Real estate | 2004 |
| Inipe Limited | Health & social care | 2024 |
| INK Connections Limited | Information & communication | 1996 |
| Inkcraft Hub Ltd | Wholesale & retail | 2026 |
| Inkite Limited | Hospitality | 2017 |
| Innovation Chain Official Ltd | Professional & scientific | 2025 |
| Innovations IT Ltd | Information & communication | 2019 |
| Innovotek Ltd | Information & communication | 2007 |
| Inscite Limited | Information & communication | 2000 |
| Insider Mart Limited | Agriculture & fishing | 2024 |
| Insight Strategic Associates Limited | Professional & scientific | 2003 |
| INSPECT360 Limited | Information & communication | 2025 |
| Inspection and Testing Limited | | 1984 |
| Inspirational Investments Limited | Real estate | 2003 |
| Inspire Beta Limited | Information & communication | 2022 |
| Inspire College of Learning Ltd | Education | 2026 |
| Instasonic Limited | Construction | 2019 |
| Instigate Unknown Ltd | Education | 2019 |
| Insulation Sheet Metal Limited | Construction | 1991 |
| Intaract Ltd | Professional & scientific | 2006 |
| Intasium Limited | | 1985 |
| Integra Accountancy Ltd | Professional & scientific | 2019 |
| Intelligent Business Solutions Limited | Professional & scientific | 2005 |
| Intelligent Lighting Services Limited | Administrative & support | 2003 |
| Inter Thermal Insulation Limited | Construction | 2003 |
| Interactiveweb Ltd | Information & communication | 2024 |
| Interbrit Ltd | Administrative & support | 2024 |
| Interior Exterior Plaster Ltd | Construction | 2016 |
| Intermediaries Transaction Exchange Ltd. | Financial services | 1998 |
| International Assessor Board for Professionals Limited | Education | 2025 |
| International Investment Services Ltd Ltd | Financial services | 2024 |
| International Transport Limited | Financial services | 1991 |
| Interpace Global UK Limited | Wholesale & retail | 2024 |
| Interstate Technical Services Limited | | 1981 |
| Intexis One Ltd | Construction | 2024 |
| Intranet Road MAP Limited | Information & communication | 2004 |
| Intus Business Consultancy Limited | Professional & scientific | 2023 |
| Invasive Limited | Hospitality | 2017 |
| Invest MA Ltd | Real estate | 2017 |
| Investec Associates Limited | Real estate | 1998 |
| Investition Anlage Ltd | Information & communication | 2026 |
| Invisible Plans Limited | Wholesale & retail | 2025 |
| Inworth Accountancy Services Ltd | Professional & scientific | 2002 |
| Ionic Auto Parts Limited | Other services | 2022 |
| IPM Construction Ltd | Construction | 2015 |
| Ippon Management Consulting Ltd | Professional & scientific | 2007 |
| Ipswich Transport Service Limited | Transport & logistics | 2016 |
| IQ Energy Centre Limited | Energy | 2018 |
| Iqaai Technologies Ltd | Wholesale & retail | 2025 |
| IRI Consulting Private Ltd | Information & communication | 2019 |
| Irichna Limited | Wholesale & retail | 2023 |
| Iris House Limited | Real estate | 2001 |
| Iron Fintech Ltd | Wholesale & retail | 2026 |
| Irtaza Kamran Ltd | Wholesale & retail | 2026 |
| Iser Consulting Ltd | Health & social care | 2026 |
| Ishaan Investments Ltd | Real estate | 2020 |
| Isherwoods Fish Wholesalers Ltd | Wholesale & retail | 2006 |
| Isinglass (Coggeshall) Management Company Limited | Real estate | 2004 |
| Isiwa Properties Limited | Real estate | 2025 |
| Island Boys & Girls Football Club Ltd | Arts & recreation | 2006 |
| Island Cyber Limited | Information & communication | 2026 |
| Island Project Management Ltd. | Information & communication | 2006 |
| Island Seafood Limited | Wholesale & retail | 1992 |