| Intermediary Communications Ltd | Other services | 2008 |
| Internal Youth Limited | Hospitality | 2018 |
| International Court of Arbitration Limited | Other services | 2024 |
| International Journal of Private HE Limited | Education | 2021 |
| International Open College U.K. Limited | Professional & scientific | 2000 |
| International Organization for Quality and Sports Excellent Ltd | Education | 2025 |
| International Sourcing Group Ltd | Wholesale & retail | 2023 |
| International Sports Management Consultancy Ltd | Professional & scientific | 2022 |
| International Tax Consulting Limited | Professional & scientific | 2017 |
| International Wine Forwarding Limited | Wholesale & retail | 1983 |
| Internationalgt Ltd | Transport & logistics | 2019 |
| Interocept Limited | Health & social care | 2022 |
| Interpham Consulting Services Ltd | Information & communication | 2023 |
| Intersite Developments Ltd | Real estate | 2017 |
| Intersite Technologies Limited | Information & communication | 1999 |
| Intertom Ltd | Information & communication | 2018 |
| Interval Consultants Limited | Professional & scientific | 2012 |
| Intuition Accountancy Limited | Professional & scientific | 2021 |
| Inuda Business Solutions Ltd | Professional & scientific | 2019 |
| Invenith Ltd | Other services | 2024 |
| Inventiff Soft Ltd | Information & communication | 2022 |
| Invento Interiors Ltd | Wholesale & retail | 2025 |
| Inverim Ltd | Professional & scientific | 2025 |
| Inverley IT Limited | Information & communication | 2025 |
| Invest Bedford Ltd | Construction | 2020 |
| Invest Connection Greenland Ltd | Real estate | 2025 |
| Investment Better Future Ltd | Real estate | 2024 |
| Investment DS Limited | Real estate | 2019 |
| Investment Properties (GB) Ltd | Professional & scientific | 2000 |
| Investment Sheff Ltd | Real estate | 2024 |
| Investment Site Services Ltd | Construction | 2021 |
| Investmove Ltd | Financial services | 2022 |
| Investor Alliance Ltd | Financial services | 2016 |
| Invex Ltd | Information & communication | 2025 |
| Invictus Care Group CIC | Health & social care | 2019 |
| Invicuts Ltd | Real estate | 2021 |
| Invisinet Wifi Solutions Ltd | Information & communication | 2014 |
| Iohec Ltd | Information & communication | 2020 |
| Ioma Ventures Limited | Administrative & support | 2020 |
| Iomi Supported Living Ltd | Health & social care | 2016 |
| ION Catering Services Ltd | Hospitality | 2023 |
| ION Locksmith Ltd | Manufacturing | 2025 |
| Iong Ltd | Construction | 2025 |
| Ionic Tech Limited | Information & communication | 2017 |
| Ionut Cleeaner Ltd | Administrative & support | 2025 |
| Ionut Driving Services Ltd | Transport & logistics | 2015 |
| Ionut Radu Limited | Transport & logistics | 2019 |
| Iony Farm Active Ltd | Transport & logistics | 2018 |
| Iordan Services Ltd | Wholesale & retail | 2014 |
| Iordana Soap Limited | Manufacturing | 2023 |
| Iota Tech Solutions Ltd | Information & communication | 2025 |
| IP Automate Ltd | Information & communication | 2026 |
| IPL Enterprises Ltd | Transport & logistics | 2025 |
| IPR Finance Group Limited | Professional & scientific | 2026 |
| Ipropertiesgroup Ltd | Real estate | 2019 |
| Iprovidehealthcare Limited | Health & social care | 2019 |
| Iprox Limited | Administrative & support | 2014 |
| IQ Driver Training Ltd | Education | 2021 |
| Iqra Property Investment Ltd | Real estate | 2025 |
| Iqworks Ltd | Other services | 2019 |
| IRA Builders Ltd | Administrative & support | 2021 |
| IRB Dryliner Ltd | Construction | 2022 |
| IRC Services Ltd | Construction | 2021 |
| Irepair Luton Limited | Wholesale & retail | 2024 |
| Ireva Technologies Limited | Real estate | 2025 |
| Irinel T Ltd | Wholesale & retail | 2022 |
| Iris Care Solutions Ltd | Professional & scientific | 2023 |
| Irmak F&V Limited | Wholesale & retail | 2023 |
| Iron Guard Management Ltd | Administrative & support | 2025 |
| Iron Heights Limited | Construction | 2025 |
| Iron K9 Ltd | Administrative & support | 2025 |
| Iron Spoon Ltd | Hospitality | 2024 |
| Ironclaw Security Limited | Administrative & support | 2025 |
| Ironfort Securities Services Ltd | Administrative & support | 2026 |
| IRS Prime Services Ltd | Construction | 2024 |
| IRS Propertie Services Ltd | Administrative & support | 2015 |
| Irvu Ltd | Other services | 2025 |
| IS IT Damp.Co.Uk Ltd | Construction | 2025 |
| IS Property Simple Ltd | Real estate | 2024 |
| ISA - MAY Limited | Real estate | 2024 |
| Isaac Global Limited | Construction | 2016 |
| Isas Holdings Ltd | Financial services | 2025 |
| Isbah Graphics Ltd | Manufacturing | 2020 |
| ISD Motors Limited | Wholesale & retail | 2022 |
| Isecureinfotech Limited | Information & communication | 2018 |
| Isense Wellness Ltd | Manufacturing | 2022 |
| ISG Plumbing & Heating Ltd | Construction | 2018 |
| Ishaa Holdings Ltd | Financial services | 2025 |
| Ishano Ltd | Wholesale & retail | 2024 |
| Ishmeet Construction Limited | Construction | 2016 |
| Ishmoney Enterprises Limited | Public administration | 2020 |
| Isidor Ltd | Construction | 2024 |
| Isiime Essentials Limited | Wholesale & retail | 2025 |
| ISL Homes Limited | Health & social care | 2024 |
| Islam Travels Ltd | Administrative & support | 2019 |
| Islamic Arts Club Ltd | Information & communication | 2025 |
| Islamic Home Tuition Ltd | Education | 2012 |
| Islamic Inspirations Ltd | Manufacturing | 2012 |
| Islands in the Sun Ltd | Wholesale & retail | 2025 |
| Islebest Holding Company Limited | Financial services | 2024 |