| Iceman Refrigeration Services.Uk Ltd | Manufacturing | 2025 |
| ICH Vehicle Technicians Ltd | Wholesale & retail | 2012 |
| Ickle Pickles Day Nursery Limited | Education | 2005 |
| ICL Media Limited | Professional & scientific | 2025 |
| Icli Digital Solutions Ltd | Information & communication | 2020 |
| Icloud Rental Ltd | Real estate | 2019 |
| ICN Corporate Limited | Administrative & support | 2010 |
| ICN Group Ltd | Real estate | 2024 |
| Icon Automotive (Nottinghamshire) Limited | Wholesale & retail | 2025 |
| Icon Education UK Ltd | Education | 2012 |
| Icon Electrical Solutions Ltd | Construction | 2013 |
| Icon Lounge Ltd | Hospitality | 2021 |
| Icon Music Records Limited | Manufacturing | 2022 |
| Iconic Ministry Limited | Wholesale & retail | 2024 |
| Icons Festival Ltd | Arts & recreation | 2019 |
| ICP Educare Group Limited | Financial services | 2023 |
| ICP Educare Holdings Limited | Financial services | 2023 |
| ICP Educare Limited | Financial services | 2023 |
| ICS Electrical Limited | Construction | 2023 |
| ICU Services Limited | Health & social care | 2023 |
| Icube Limited | Professional & scientific | 2002 |
| Icwebpro Ltd | Information & communication | 2019 |
| ICY Healthcare Limited | Health & social care | 2019 |
| ID Architecture Solutions Limited | Construction | 2019 |
| ID Direct Cleaning Ltd | Administrative & support | 2020 |
| ID Music Ltd | Arts & recreation | 2009 |
| Idaco Consulting Limited | Health & social care | 2015 |
| Idameneo (UK) Limited | Extraterritorial | 1959 |
| IDC Education-Uk Ltd | Education | 2024 |
| IDD Commercial Limited | Construction | 2017 |
| Idea Cabin Ltd | Information & communication | 2013 |
| Idea Fairy Limited | Professional & scientific | 2024 |
| Idea IS Good Ltd | Manufacturing | 2016 |
| Idea MAC Ltd | Manufacturing | 2023 |
| Idea Vision UK Ltd | Professional & scientific | 2018 |
| Ideagen Huddle Ltd | Administrative & support | 2006 |
| Ideagen Limited | Information & communication | 1993 |
| Ideagen Opsbase Limited | Information & communication | 2018 |
| Ideagen Software Limited | Information & communication | 1973 |
| Ideagen Technology Limited | Information & communication | 2006 |
| Ideal Car Ltd | Wholesale & retail | 2015 |
| Ideal Dairies Ltd | Hospitality | 2013 |
| Ideal FM Services Limited | Households | 2023 |
| Ideal Home Solutions (Nottingham) Ltd | Administrative & support | 2017 |
| Ideal Pristine Cleaners Ltd | Administrative & support | 2025 |
| Ideal Property Consultancy Ltd | Real estate | 2017 |
| Ideal Realty Ltd | Real estate | 2025 |
| Ideal Services Group Limited | Extraterritorial | 2007 |
| Ideal Shutters & Shades Ltd | Wholesale & retail | 2020 |
| Ideapower Designs Limited | Wholesale & retail | 1994 |
| IDEAS4CAREERS (UK) Ltd | Education | 2012 |
| Ideavent Ltd | Information & communication | 2008 |
| Identity Protect Limited | Information & communication | 2010 |
| IDI Property Limited | Real estate | 2025 |
| Idio Limited | Information & communication | 2026 |
| IDL Art Ltd | Other services | 2019 |
| Idmann Group UK Limited | Real estate | 2023 |
| Idrilay Ltd | Wholesale & retail | 2025 |
| IDS Enterprises Limited | Professional & scientific | 2024 |
| Idwal Investments | Financial services | 2020 |
| IEF Holdings Ltd | Financial services | 2025 |
| Ieffects Ltd | Arts & recreation | 2012 |
| IEH Consulting Limited | Professional & scientific | 2015 |
| IEL Property Ltd | Real estate | 2026 |
| IES Lean Systems Limited | Professional & scientific | 2012 |
| Ieso Limited | Professional & scientific | 2025 |
| IET Limited | Professional & scientific | 2013 |
| IF Civils Ltd | Construction | 2017 |
| IF SHE SO Pleases Ltd | Wholesale & retail | 2021 |
| IF the Shoe Fits Limited | Wholesale & retail | 2011 |
| IFA.1 Limited | Financial services | 2003 |
| Ifaaco Ltd | Arts & recreation | 2024 |
| Ifgautomotive Ltd | Wholesale & retail | 2022 |
| Ifigeneia Vergoulia Limited | Health & social care | 2025 |
| Ifit-Bts Limited | Construction | 2018 |
| Ifix Technologies Ltd | Information & communication | 2017 |
| Iflooring Ltd | Wholesale & retail | 2019 |
| Iform Legal Limited | Professional & scientific | 2025 |
| Iftec Ltd. | Information & communication | 2014 |
| Iftf Holding Limited | Financial services | 2019 |
| Ifti's Medical Services Limited | Health & social care | 2015 |
| Iftime Ltd | Transport & logistics | 2016 |
| Iftone Limited | Information & communication | 2026 |
| IG Fisheries Limited | Agriculture & fishing | 2009 |
| IG Golf Limited | Wholesale & retail | 2020 |
| IG Loft Solutions Limited | Professional & scientific | 2020 |
| IGB Investments Ltd | Real estate | 2021 |
| Igenix Holdings Ltd | Professional & scientific | 2019 |
| Iggy.Ltd.Uk Ltd | Transport & logistics | 2011 |
| Igloo Digs Limited | Hospitality | 2014 |
| Igloo Plumbing and Heating Services Ltd | Construction | 2016 |
| Igloo Property Consultancy Limited | Real estate | 2021 |
| IGM Property Investments Limited | Real estate | 2025 |
| IGM Solutions Limited | Other services | 2022 |
| Igma Properties Ltd | Real estate | 2025 |
| Ignalina Bidco Limited | Financial services | 2026 |
| Ignite Alternative Provision Ltd | Education | 2024 |
| Ignite Films Limited | Professional & scientific | 2020 |
| Ignite Futures Ltd | Education | 2006 |
| Ignite GAS Plumbing and Electrics Ltd | Construction | 2019 |