| IAN Colman Enterprises Limited | Transport & logistics | 2013 |
| IAN Hyde & Associates Limited | Other services | 2003 |
| IAN James Cooper Consulting Ltd | Professional & scientific | 2021 |
| IAN Moncur Limited | Wholesale & retail | 2003 |
| IAN Norris Architectural Design Ltd | Professional & scientific | 2021 |
| IAN Smalley Caravan Services Limited | Administrative & support | 2020 |
| Iancul Creative Ltd | Information & communication | 2019 |
| IB Group Services Ltd | Construction | 2020 |
| Ibbertson Motorsport Racing Ltd | Arts & recreation | 2017 |
| Ibbotson Group Ltd | Manufacturing | 2012 |
| Ibex ALL Access Ltd | Professional & scientific | 2019 |
| Ibis Computer and Management Services Limited | Information & communication | 1994 |
| IBL Estates Ltd | Real estate | 2024 |
| Ibrand Limitless Ltd | Wholesale & retail | 2021 |
| IC3 Attire Limited | Manufacturing | 2018 |
| Icam Automation Solutions Ltd | Manufacturing | 2019 |
| Icandi Limited | Professional & scientific | 2002 |
| Icars (Swadlincote) Ltd | Transport & logistics | 2012 |
| Icat Solutions Ltd | Administrative & support | 2013 |
| ICD Property Developments Ltd | Other services | 2014 |
| Ice Cream DUB Limited | Hospitality | 2018 |
| Icefresh Foods Limited | Wholesale & retail | 1978 |
| Icelanding Ltd | Health & social care | 2023 |
| Iceni Advisory Limited | Professional & scientific | 2002 |
| Iceni Anglia Limited | Agriculture & fishing | 1979 |
| Iceni Audio Limited | Manufacturing | 2015 |
| Iceni Care Limited | Health & social care | 2011 |
| Iceni Carpentry Ltd | Construction | 2019 |
| Iceni Construction Limited | Construction | 2024 |
| Iceni Court Management Company Limited | Real estate | 2001 |
| Iceni Deer Management Ltd | Professional & scientific | 2019 |
| Iceni Electrical Contractors Ltd | Construction | 2024 |
| Iceni Group Holdings Limited | Real estate | 2026 |
| Iceni Group Property’S Limited | Real estate | 2025 |
| Iceni Ice Cream and Events Ltd | Hospitality | 2025 |
| Iceni International Limited | Financial services | 2003 |
| Iceni Lettings & Property Ltd | Real estate | 2024 |
| Iceni RE Ltd | Real estate | 2026 |
| Iceni Seedcorn Fund LLP | | 2002 |
| Iceni Training Limited | Education | 2019 |
| Iceni Truck & Van Limited | Extraterritorial | 2009 |
| Iceni Warriors Martial Arts Limited | Arts & recreation | 2025 |
| Iceni Watch Repairs Ltd | Other services | 2026 |
| Iceni Wholesale Ltd | Wholesale & retail | 2023 |
| Icenimdt Ltd | Administrative & support | 2019 |
| Ichange Business Solutions Limited | Real estate | 2015 |
| Ichiban Events Limited | Arts & recreation | 2017 |
| ICO Limited | Professional & scientific | 2003 |
| Icon Planning and Environmental Ltd | Professional & scientific | 2016 |
| Iconic Norwich Limited | Real estate | 2021 |
| Iconic Norwich Properties Limited | Real estate | 2023 |
| Iconik Marketing Ltd | Professional & scientific | 2025 |
| Icoriolis Limited | Information & communication | 2015 |
| Icpn Limited | Information & communication | 2024 |
| ICS Beauty Ltd | Health & social care | 2025 |
| ICT Coaches Ltd | Transport & logistics | 2018 |
| ICY Engineering Ltd | Manufacturing | 2025 |
| ID Matters Ltd | Other services | 2022 |
| Idda Courses and Events Limited | Education | 2025 |
| Idea Farm PR Ltd | Arts & recreation | 2019 |
| Ideal Dreams Ltd | Hospitality | 2019 |
| Ideal EA Limited | Administrative & support | 2022 |
| Ideal Hire Ltd | Construction | 2012 |
| Ideal Placement Recruitment Specialists Limited | Extraterritorial | 2012 |
| Ideal Scaffolding (East Anglia) Holdings Ltd | Financial services | 2020 |
| Ideal Scaffolding (East Anglia) Ltd. | Construction | 2002 |
| Idence Limited | Professional & scientific | 2011 |
| Idenfo Limited | Information & communication | 2019 |
| Identity Security Consultancy Ltd | Information & communication | 2019 |
| Idfrailsys Consultant Services Limited | Administrative & support | 2009 |
| Idivide Limited | Information & communication | 2018 |
| Idpt Ltd | Construction | 2024 |
| Idtd Services Limited | Professional & scientific | 2010 |
| Idyll Country Ltd | Construction | 2017 |
| Idyllic Spaces Ltd | Real estate | 2025 |
| IE Solutions Ltd | Education | 2015 |
| IFA Financial Services (UK) Ltd. | Financial services | 2006 |
| IFC Tunstead Limited | Extraterritorial | 2017 |
| Ifinstar Limited | Administrative & support | 2015 |
| Ifis Group Ltd | Wholesale & retail | 2026 |
| IFK Ltd | Transport & logistics | 2020 |
| IFL Business Services Limited | Professional & scientific | 2010 |
| IFM Lettings Ltd | Real estate | 2025 |
| Ifma Healthcare Ltd | Health & social care | 2021 |
| IFP Associates Limited | Financial services | 2006 |
| IFR Enterprises Limited | Professional & scientific | 1997 |
| IFR NRP Capital Limited | Professional & scientific | 2012 |
| IGD Transport Ltd | Transport & logistics | 2026 |
| Ighs Services Limited | Professional & scientific | 2016 |
| Ignite Accelerator Services Limited | Professional & scientific | 2025 |
| Ignite Heating Spares Ltd | Other services | 2010 |
| Ignite Martial Arts Ltd | Arts & recreation | 2023 |
| Ignite Music Ltd | Arts & recreation | 2022 |
| Ignition Holdings Ltd | Extraterritorial | 2022 |
| Igzalt Limited | Real estate | 2022 |
| Ihalo Limited | Professional & scientific | 2007 |
| II6 Ltd | Professional & scientific | 2016 |
| Iicon Limited | Information & communication | 1990 |
| IJL Motor Sport Limited | Real estate | 2013 |
| Ikafkias Limited | Professional & scientific | 2022 |