| Idle Properties Ltd | Financial services | 2023 |
| Idle White Hart Ltd | Hospitality | 2022 |
| IDM Courier Ltd | Transport & logistics | 2021 |
| Idoc Solutions Ltd | Information & communication | 2020 |
| Idrees Khan Ltd | Wholesale & retail | 2025 |
| Idyllic Developments Ltd | Construction | 2020 |
| IE Safety Solutions Limited | Construction | 2024 |
| IF Collective Ltd | Arts & recreation | 2018 |
| Ifddw Limited | Construction | 2025 |
| Ifgl Monocon Holdings Limited | Professional & scientific | 2005 |
| Ifix Interiors Limited | Construction | 2018 |
| Iflow Limited | Manufacturing | 2013 |
| Ifp-Labs UK South Yorkshire Limited | Professional & scientific | 2004 |
| IFS (Lincolnshire) Ltd | Health & social care | 2015 |
| IFS (Yorkshire) Ltd | Health & social care | 2015 |
| IFS Property Traders Ltd | Real estate | 2025 |
| IFS Risk Solutions (UK) Limited | Financial services | 2004 |
| IGB Comms Limited | Administrative & support | 2018 |
| Igloo Construction Group Ltd | Financial services | 2025 |
| Igloo Contractors Ltd | Construction | 2023 |
| Igloo Surfaces Limited | Construction | 2012 |
| Igma 22 Ltd | Transport & logistics | 2023 |
| Ignas S Limited | Transport & logistics | 2016 |
| Ignite Auto Studio Ltd | Wholesale & retail | 2025 |
| Ignite Homes Limited | Construction | 2012 |
| Ignite Property Development Ltd | Real estate | 2017 |
| Ignition Skills Limited | Education | 2026 |
| IGO Walkies Ltd | Wholesale & retail | 2019 |
| Igors Deliveries Ltd | Transport & logistics | 2025 |
| Ihandle Ltd | Construction | 2023 |
| Ihus Group Ltd | Professional & scientific | 2020 |
| Ihus Homes Limited | Professional & scientific | 2014 |
| IJB Rentals Limited | Real estate | 2020 |
| Ikconn Healthcare Group Limited | Health & social care | 2024 |
| IKD Law Consultancy Ltd | Professional & scientific | 2014 |
| Ikiz Ltd | Hospitality | 2024 |
| Ikonyc Ltd | Real estate | 2025 |
| Ilbay Catering Ltd | Hospitality | 2022 |
| Ilber Limited | Hospitality | 2025 |
| Ilie Gheorghe Ltd | Construction | 2025 |
| Ilie Stefan Limited | Construction | 2025 |
| Iline Ltd | Real estate | 2003 |
| Illingworth Fire Protection Ltd | Construction | 2009 |
| Illis Limited | Real estate | 2019 |
| Illuma-Tech Ltd | Construction | 2014 |
| Illumibox Ltd | Professional & scientific | 2022 |
| Illuminate Care Group Limited | Hospitality | 2024 |
| Illuminate Holdings Limited | Hospitality | 2025 |
| Ilyas Catering Ltd | Hospitality | 2024 |
| IM Care Limited | Health & social care | 2014 |
| IM Fast Ltd | Transport & logistics | 2025 |
| Im&A Limited | Professional & scientific | 2019 |
| IMA Logistics Ltd | Transport & logistics | 2024 |
| Iman Zain Consultancy Ltd | Real estate | 2003 |
| Iman Zain Investments Ltd | Real estate | 2007 |
| IMJ Construction Services Ltd | Construction | 2025 |
| IMJ Estates Ltd | Real estate | 2026 |
| Immaculate Spaces Ltd | Administrative & support | 2025 |
| Immersiai Ltd | Information & communication | 2026 |
| Immotech Ltd | Administrative & support | 2019 |
| Impact 4 YOU LLP | | 2018 |
| Impact Club CIC | Arts & recreation | 2025 |
| Impact Media Management Ltd | Administrative & support | 2020 |
| Impact Project Services Ltd | Construction | 2019 |
| Imperial Automotive & Property Limited | Wholesale & retail | 2001 |
| Imperial Imports Ltd | Wholesale & retail | 2015 |
| Imperium Structures Ltd | Real estate | 2025 |
| Impilo Living Services Limited | Transport & logistics | 2025 |
| Impossible Polymers Ltd | Manufacturing | 2022 |
| Improvement in School Through Handwriting and Art Limited | Education | 2019 |
| Imran Dental Ltd | Health & social care | 2023 |
| Imrie Jones Limited | Manufacturing | 2012 |
| IMS (North) Limited | Information & communication | 2005 |
| IMS Maisons Limited | Real estate | 2020 |
| Imship Netherlands Ltd | Transport & logistics | 2004 |
| Imyco Construction Limited | Construction | 2006 |
| IN & OUT Building Solutions Ltd | Construction | 2025 |
| IN Parallel Productions CIC | Arts & recreation | 2024 |
| IN Rovers WE Trust CIC | Health & social care | 2024 |
| In-Play Online Ltd | Extraterritorial | 2016 |
| In-Play Sports Analysis Ltd | Arts & recreation | 2015 |
| In-Play Sports Ltd | Arts & recreation | 2016 |
| IN2D Ltd | Transport & logistics | 2018 |
| Inativ Limited | Transport & logistics | 2020 |
| Inavision Limited | Education | 2011 |
| Inci Foods Ltd | Hospitality | 2025 |
| Incision-Uk Ltd | Extraterritorial | 2022 |
| Inclusive Education Training and Support Limited | Education | 2015 |
| Incomecentre Limited | Wholesale & retail | 1992 |
| Indago Clinical Management Ltd | Professional & scientific | 2025 |
| Indah-Lotus Limited | Wholesale & retail | 2026 |
| Indemnisure Ltd | Information & communication | 2020 |
| Independent Cigarette Company Limited | Professional & scientific | 1983 |
| Independent Food Services Limited | Professional & scientific | 1967 |
| Independent Football Coaching (IFC) Ltd | Arts & recreation | 2024 |
| Independent Living Housing Solutions Ltd | Hospitality | 2015 |
| Independent Measuring Services Limited | Administrative & support | 2005 |
| Independent Service Bookings Ltd | Administrative & support | 2008 |
| Independent-Therapies Ltd | Health & social care | 2019 |
| Index Construction Ltd | Construction | 2023 |