| IB Heating & Renewables Ltd | Construction | 2025 |
| IB Heating Ltd | Construction | 2016 |
| IBC2GO Limited | Wholesale & retail | 2017 |
| Ibex International Forwarding Limited | Professional & scientific | 1982 |
| Ibless Limited | Health & social care | 2019 |
| IBS Investments Limited | Real estate | 2024 |
| IC EDU Solutions Ltd | Education | 2017 |
| Ican Fire Solution Limited | Public administration | 2023 |
| ICARE24 Healthcare Limited | Health & social care | 2022 |
| Ice Cold Electronics Ltd | Construction | 2023 |
| Iceni Financial Advisers Limited | Financial services | 2012 |
| Iceni IFA Limited | Financial services | 2023 |
| Icenine Drinks Ltd | Manufacturing | 2019 |
| Ickburgh Road Limited | Real estate | 2016 |
| ICM (Kent) Ltd | Manufacturing | 2014 |
| Icmh Limited | Administrative & support | 2012 |
| Iconology Ltd | Information & communication | 1998 |
| ICU Medical (SM) Limited | Manufacturing | 1970 |
| ICU Medical 2020 Limited | Professional & scientific | 2019 |
| ICU Medical Bidco Ltd | Manufacturing | 2021 |
| ICU Medical Group Limited | Professional & scientific | 2004 |
| ICU Medical International Limited | Manufacturing | 1940 |
| ICU UK Medical Limited | Manufacturing | 2016 |
| ID8 Concepts Limited | Professional & scientific | 2023 |
| Ideal Design Flooring Limited | Wholesale & retail | 2005 |
| Ideal Estimating Limited | Other services | 2014 |
| Ideal Health Solutions Ltd | Health & social care | 2022 |
| Ideas Infinity Limited | Information & communication | 2009 |
| Ideas Kitchen and Bedrooms Ltd | Construction | 2017 |
| Ideaworks Marine Limited | Professional & scientific | 2006 |
| Idental Care 24 Ltd | Health & social care | 2007 |
| Identify Building Services Limited | Construction | 2015 |
| Idream Limited | Real estate | 2019 |
| Idyllic Holidays Limited | Professional & scientific | 2016 |
| IEB Estates Limited | Construction | 2022 |
| IF Design & Build Ltd | Construction | 2026 |
| If&I Ltd | Health & social care | 2025 |
| Ifetedo Descendants' Association Ltd | Other services | 2022 |
| Ifini Limited | Information & communication | 2014 |
| Ifix 4 YOU Limited | Wholesale & retail | 2019 |
| Ifixwindows Ltd | Construction | 2022 |
| Igaming Marketing Solutions Ltd | Professional & scientific | 2025 |
| Igard Limited | Professional & scientific | 2018 |
| IGC Civils Ltd | Construction | 2019 |
| Ignish Publishing House Ltd | Information & communication | 2014 |
| Ignite Heating (Kent) Limited | Administrative & support | 2012 |
| Ignorant Bliss Limited | Hospitality | 2018 |
| IGO Group Limited | Financial services | 2020 |
| Igoe Financial Ltd | Administrative & support | 2015 |
| IK Spatial Design Ltd | Professional & scientific | 2013 |
| Ikigai Holistic Ltd | Arts & recreation | 2018 |
| Ikon Global Ltd | Professional & scientific | 2017 |
| Ikon Residentials Ltd | Real estate | 2018 |
| Ikra UK Ltd. | Transport & logistics | 2006 |
| Ilhan (Kent) Ltd | Hospitality | 2011 |
| Iliyan Cleaning Limited | Administrative & support | 2018 |
| Illum ATE Ltd | Other services | 2025 |
| Illustrious Properties Limited | Real estate | 2019 |
| IM & T UK Limited | Information & communication | 2011 |
| Image Canada Group Limited | Financial services | 2025 |
| Image Court Management Company Ltd | Households | 2019 |
| Image Playgrounds Limited | Manufacturing | 2022 |
| Image Source Limited | Professional & scientific | 2022 |
| Imagine This (UK) Limited | Construction | 2001 |
| IMB Capital Ltd | Financial services | 2022 |
| IMC Enterprises Limited | Other services | 1998 |
| Imhotep Music Investments Limited | Financial services | 2016 |
| Imhotep Music Limited | Information & communication | 2010 |
| Imhotep Productions Ltd | Information & communication | 2021 |
| Imhotep Publishing Limited | Arts & recreation | 2016 |
| Imhotep Records Limited | Information & communication | 2025 |
| Imhotep Touring LLP | | 2013 |
| Imka Technologies Ltd | Information & communication | 2016 |
| Imli Cash & Carry Ltd | Wholesale & retail | 2024 |
| Immaculate Cleaning and Maintenance Services (Icms) Ltd | Construction | 2014 |
| Immanuel Solutions Ltd | Information & communication | 2015 |
| Immortal Film Ltd | Information & communication | 2024 |
| Immortal-Insects Ltd | Wholesale & retail | 2024 |
| Imnos Developments Limited | Real estate | 2021 |
| Imnos Properties Limited | Real estate | 2017 |
| Imperial Green Limited | Construction | 2010 |
| Imperial Green Management Company Limited | Real estate | 2010 |
| Imperial Green Wisley RTM Company Limited | Real estate | 2010 |
| Imperial Healthcare Solutions Ltd | Health & social care | 2025 |
| Imperial Metal Recycling Ltd | Water & waste | 2023 |
| Imperial Vending Services Limited | Administrative & support | 1991 |
| Imperium (Pest Control) Limited | Administrative & support | 2021 |
| Impero Capital Limited | Financial services | 2021 |
| Implanden Limited | Health & social care | 2024 |
| Impressive Media Ltd | Professional & scientific | 2025 |
| IMR Properties Limited | Construction | 2010 |
| IMS Transport Services Ltd | Transport & logistics | 2024 |
| IN & CZ Limited | Construction | 2014 |
| IN Focus News Ltd | Professional & scientific | 2007 |
| IN Living Memories Limited | Information & communication | 2025 |
| Incartigo Limited | Transport & logistics | 2020 |
| Incense Themes and Decor Limited | Administrative & support | 2016 |
| Includes US 2 | Health & social care | 2010 |
| Inclusion Ignite Limited | Education | 2025 |
| Inclusive Talent Ltd | Administrative & support | 2020 |