| IAN Wootton Pallets & Packing Cases Ltd | Manufacturing | 2023 |
| IBA Property Services Ltd | Professional & scientific | 2026 |
| IBA Property Solutions Ltd | Real estate | 2021 |
| IBC Adapters Limited | Construction | 2015 |
| IC 2 UK Ltd | Administrative & support | 2006 |
| Icaps Europe Ltd | Manufacturing | 2011 |
| Iconics UK Services Limited | Information & communication | 2008 |
| Iconicshift AI Limited | Other services | 2025 |
| ID Mechanical Engineering Services Limited | Professional & scientific | 2022 |
| Idac 2.5 Ltd | Construction | 2023 |
| Idac Development Services Ltd | Real estate | 2025 |
| Idrive 24-7 Ltd | Transport & logistics | 2024 |
| IE Burke Ltd | Administrative & support | 2021 |
| Ifly Spitfire Simulator Ltd | Arts & recreation | 2024 |
| Ignite Media Prod Ltd | Information & communication | 2026 |
| IH Travels Ltd | Wholesale & retail | 2020 |
| IKA Traders Ltd | Wholesale & retail | 2013 |
| Ikesinachi and Son’S Limited | Health & social care | 2023 |
| Ikon Barbers Great Western Limited | Other services | 2015 |
| Ikon Barbers Hagley Limited | Other services | 2019 |
| Ilanila Limited | Wholesale & retail | 2024 |
| Ilyas Services (GB) Ltd | Professional & scientific | 2013 |
| Imaan Travel & Car Hire Ltd | Transport & logistics | 2026 |
| Imajico Ltd | Professional & scientific | 2002 |
| Imarius Limited | Transport & logistics | 2017 |
| Immajed Ventures Ltd | Wholesale & retail | 2025 |
| Immb Ltd | Wholesale & retail | 2026 |
| Imperial Kilt Products Limited | Wholesale & retail | 2022 |
| Impex Bulk Ltd | Transport & logistics | 2025 |
| Improvement Systems Limited | Professional & scientific | 2006 |
| Impulseintack Ltd | Wholesale & retail | 2019 |
| Independent Occupational Therapy Services NLE Ltd | Health & social care | 2022 |
| Index Mortgages Limited | Financial services | 2004 |
| Indiro Trading Ltd | Wholesale & retail | 2025 |
| Industrial Labels & Nameplates Limited | Manufacturing | 2015 |
| Industrial Relations & Development Consultancy Ltd | Hospitality | 2005 |
| Infinite Futures Limited | Health & social care | 2021 |
| Infinity Investors Ltd | Real estate | 2023 |
| Infinity Mortgages Limited | Financial services | 2023 |
| Inform & Perform Limited | Arts & recreation | 2015 |
| Ingospec Commercial Limited | Manufacturing | 2000 |
| Ingram (Foundry) Industries Limited | Manufacturing | 1990 |
| Inkersole Limited | Construction | 2016 |
| Inlite Ltd | Wholesale & retail | 2021 |
| INNOV4TE CIC | Education | 2021 |
| Innovating Better Healthcare (IBH) Ltd | Education | 2025 |
| Innovoffice Ltd | Wholesale & retail | 2023 |
| Inovativ Ltd | Transport & logistics | 2024 |
| Inshore Support Holdings Limited | Financial services | 2015 |
| Inshore Support Limited | Health & social care | 1999 |
| Insightel Limited | Extraterritorial | 2013 |
| Insolation Solar Ltd | Construction | 2020 |
| Inspection & Packaging Solutions Ltd | Professional & scientific | 2014 |
| Inspiral Solutions Ltd | Professional & scientific | 2012 |
| Inspired Accountancy Services Ltd | Professional & scientific | 2017 |
| Inspired Business Development Ltd | Professional & scientific | 2024 |
| Inspired by Isaiah & Friends CIC | Education | 2026 |
| Inspired Roofing Solutions Ltd | Construction | 2024 |
| Instant Business Manager Limited | Financial services | 2010 |
| Insulation Wall Solution Ltd | Construction | 2014 |
| Integral Propco Ltd | Real estate | 2024 |
| Integral Roofing and Maintenance Services Ltd | Construction | 2014 |
| Integral Roofing Maintenance Services Ltd | Construction | 2015 |
| Integral Windows and Conservatories Ltd | Construction | 2019 |
| Integrated Management Systems Limited | Professional & scientific | 2007 |
| Integrated Renewables Ltd | Construction | 2020 |
| Integrity Eco Solutions Ltd | Administrative & support | 2021 |
| Interior Contractors (Midland) Ltd | Construction | 2023 |
| International Wire Industries Limited | Financial services | 2022 |
| Interplas Coatings (Holdings) Limited | Other services | 2017 |
| Interplas Coatings Limited | Manufacturing | 1991 |
| Intertech Holdings & Investments Ltd | Financial services | 2024 |
| Invell Limited | Real estate | 2024 |
| Inventdecor Limited | Extraterritorial | 1995 |
| Investa Limited | Real estate | 2000 |
| Investment 2026 Limited | Financial services | 2025 |
| Investments 2025 Limited | Real estate | 2024 |
| Ionut Logistic Group Ltd | Transport & logistics | 2018 |
| IP Corp Ltd | Extraterritorial | 2025 |
| IPL (UK) Limited | Administrative & support | 1997 |
| Iqbal Builders Midlands Ltd | Construction | 2025 |
| IRP (2010) Limited | Administrative & support | 2010 |
| Isaacs Properties Limited | Professional & scientific | 2016 |
| Isabella's Homes Limited | Health & social care | 2014 |
| Isaiah Preston Limited | Professional & scientific | 1917 |
| ISK Imperial Ltd | Construction | 2026 |
| Ispark Data & Electrical Services Limited | Construction | 2014 |
| Isquared EPI Ltd | Professional & scientific | 2024 |
| Issuecrown Limited | Professional & scientific | 1981 |
| IT Inspired Solutions Ltd | Information & communication | 2018 |
| IT River Ltd | Information & communication | 2026 |
| Italian Connections & Affinities UK Limited | Construction | 2024 |
| Italian Stallion Ltd | Hospitality | 2026 |
| ITC Electrical Services (Dudley) Limited | Construction | 2010 |
| ITS Guru Ltd | Information & communication | 2014 |
| It’S a Catch Ltd | Hospitality | 2025 |
| Iverley Pastures Limited | Extraterritorial | 2016 |
| Iveryscenes Media Ltd | Administrative & support | 2023 |
| IVY Wild Ltd | Wholesale & retail | 2018 |
| IW Baldwin Ltd | Administrative & support | 2022 |