| Icarus RLE Limited | Other services | 2021 |
| Icat Interiors Ltd | Construction | 2021 |
| Icat Property Ltd | Real estate | 2024 |
| Ice Investments Limited | Financial services | 2016 |
| Icelend Ltd | Energy | 2025 |
| ICG Smart Cosmetics Ltd | Information & communication | 2020 |
| Icharge Technology Ltd | Other services | 2026 |
| ICO Tourist Businesses Limited | Administrative & support | 2018 |
| Ideal Design West Midland Ltd | Construction | 2016 |
| IDG Estates Limited | Construction | 2025 |
| Idl-Bg Ltd | Professional & scientific | 2013 |
| Idler Group Ltd | Financial services | 2024 |
| Idler Property Ltd | Real estate | 2025 |
| Idlg Ltd | Manufacturing | 2022 |
| IF Only They Knew Ltd | Other services | 2022 |
| Iglobe Consultancy Limited | Information & communication | 2016 |
| Iglobe Technologies Limited | Information & communication | 2010 |
| Igloo Consultancy Services Ltd | Information & communication | 2018 |
| Ignis Limited | Administrative & support | 1988 |
| Igr.Nrr. Ltd | Hospitality | 2026 |
| Iguru Technology Limited | Information & communication | 2024 |
| Ijale Holdings Ltd | Real estate | 2025 |
| Ijia Electrics Ltd | Construction | 2021 |
| IJP Investments Ltd | Administrative & support | 2025 |
| IKO Cleaning Service Ltd | Administrative & support | 2018 |
| Ikuloburu Holdings Limited | Transport & logistics | 2017 |
| Ilari EYE Solutions Limited | Health & social care | 2026 |
| Ilex Studio Limited | Wholesale & retail | 2019 |
| ILF Property Company Limited | Real estate | 2023 |
| Ilhan Property Investments Limited | Real estate | 2025 |
| Illyrian Power PLC | Financial services | 2018 |
| Imac Building Services Ltd | Construction | 2008 |
| Image Retrieval Ltd | Administrative & support | 2019 |
| Imaging Services(Uk) Ltd | Health & social care | 2022 |
| IMB Logistics Ltd | Transport & logistics | 2025 |
| Imigongo Labs Ltd | Information & communication | 2024 |
| Imilce Gardens Limited | Other services | 2010 |
| Iminka Ltd | Professional & scientific | 2019 |
| Imisepden Inc Ltd | Health & social care | 2019 |
| Immaculate Skin Ltd | Other services | 2023 |
| Impact Foods International Ltd | Hospitality | 2016 |
| Impact Life International Ltd | Financial services | 2021 |
| Impactivise Advisors Limited | Professional & scientific | 2022 |
| Impera Opus Group Ltd | Professional & scientific | 2026 |
| Imperial Media London Ltd | Professional & scientific | 2026 |
| Imperium Parts Limited | Wholesale & retail | 2025 |
| Impress Communications Limited | Professional & scientific | 1994 |
| Impulse Music Travel Limited | Transport & logistics | 2001 |
| IMR Property and Investments Limited | Professional & scientific | 1995 |
| IN 2 Image Marketing Ltd | Professional & scientific | 2006 |
| Inanya Limited | Information & communication | 2026 |
| Inasa Ltd | Hospitality | 2024 |
| IND Business Consultancy Limited | Information & communication | 2022 |
| Indi Bakes Cakes Ltd | Wholesale & retail | 2023 |
| Indian Takeaway Petts Wood Ltd | Hospitality | 2024 |
| Indiya Catering Ltd | Hospitality | 2025 |
| Indiya Cloud Kitchen Limited | Hospitality | 2025 |
| Indiya Food Limited | Hospitality | 2023 |
| Indoors & Outdoors Construction Ltd | Construction | 2016 |
| Indukara Limited | Professional & scientific | 2011 |
| Indukara Property Ltd | Real estate | 2019 |
| Indus Advisors Limited | Professional & scientific | 2025 |
| Infinite Property Investment Ltd | Real estate | 2019 |
| Infinity B&D Ltd | Construction | 2024 |
| Inflecta Consulting Limited | Professional & scientific | 2025 |
| Infosec IT Solutions Ltd | Information & communication | 2025 |
| Infra Europe Limited | Other services | 2012 |
| Inhype Wraps Ltd | Wholesale & retail | 2024 |
| Inicio Advisory Limited | Professional & scientific | 2022 |
| Innerground Music Limited | Manufacturing | 2003 |
| Innocence Ltd | Administrative & support | 2022 |
| Innovate Parking Ltd | Other services | 2025 |
| Innovations Hair & Beauty Unisex Studio Limited | Other services | 2004 |
| Innovative Thermoanalytic Instruments Limited | Manufacturing | 2010 |
| Inoconnect Ltd | Information & communication | 2021 |
| Inovtech IT Limited | Information & communication | 2018 |
| Inquisitive HR Ltd | Administrative & support | 2022 |
| Inside Build Ltd | Construction | 2020 |
| Insolum Projects Ltd | Construction | 2010 |
| Inspection and Consultancy Services Limited | Professional & scientific | 1998 |
| Inspirational Landscapes & Maintenance Ltd | Professional & scientific | 2017 |
| Inspirational Talks Limited | Education | 2018 |
| Inspire Locums Limited | Health & social care | 2016 |
| Inspire Property Partners Ltd | Real estate | 2019 |
| Inspired by the Game Ltd | Arts & recreation | 2026 |
| Inspired Lane HQ Ltd | Financial services | 2011 |
| Inspirit Back to Nature Ltd | Manufacturing | 2025 |
| Inspyre Property Ltd | Real estate | 2025 |
| Install Archive Ltd. | Professional & scientific | 2013 |
| Instinct Films Limited | Professional & scientific | 2018 |
| Intaway Resourcing Ltd | Administrative & support | 2004 |
| Integra AI Ltd | Information & communication | 2025 |
| Intelliblocks Ltd | Manufacturing | 2017 |
| Inter-Trans Global Limited | Transport & logistics | 2010 |
| Interco Contracts Ltd | Construction | 2020 |
| Interior Creations UK Limited | Manufacturing | 2022 |
| Interior Shopfitters (Kent) Limited | Construction | 2015 |
| Interior World Limited | Professional & scientific | 2025 |
| Interiors at SIX Limited | Professional & scientific | 2025 |
| Interiors UP Ltd | Construction | 2018 |