| I H S Carpentry Limited | Construction | 2019 |
| I Mushayi Limited | Health & social care | 2014 |
| I W Martin & Sons Ltd | Construction | 2009 |
| I&A Protint Ltd | Wholesale & retail | 2025 |
| I.A.B Health Ltd | Health & social care | 2024 |
| I2CDESIGN Ltd | Construction | 2012 |
| Iadr Ltd | Professional & scientific | 2020 |
| IAK Construction Ltd | Construction | 2016 |
| IAN R Smith Consulting Ltd | Professional & scientific | 2024 |
| IAN Tremain Electrical Consultant Limited | Wholesale & retail | 2005 |
| Iassist Apps Ltd | Information & communication | 2020 |
| Ibdd Limited | Administrative & support | 2022 |
| Ibef Care Services Limited | Health & social care | 2023 |
| Ibi's Kitchen Ltd | Hospitality | 2015 |
| Ibiza Glow (Mottingham) Ltd | Other services | 2026 |
| IC Mini Digger and Plant Hire Ltd | Administrative & support | 2024 |
| Icare Connect Services Ltd | Administrative & support | 2026 |
| Icomera UK Limited | Information & communication | 2007 |
| Icon Inspire Ltd | Other services | 2023 |
| Icon Modular Limited | Professional & scientific | 2001 |
| Icon Theatre | Arts & recreation | 2002 |
| Iconz Fashion Ltd | Wholesale & retail | 2025 |
| Icoros Limited | Administrative & support | 2006 |
| ICY Calls Limited | Manufacturing | 2009 |
| IDE Real Estate Limited | Real estate | 2014 |
| Ideal Home & Garden Improvements Ltd | Construction | 2020 |
| Ideashacks Ventures Limited | Real estate | 2024 |
| Identity Detailing Ltd | Wholesale & retail | 2026 |
| Identity Graphic Innovation Ltd | Wholesale & retail | 2014 |
| Identity Wraps Ltd | Wholesale & retail | 2015 |
| IDL Joinery Limited | Manufacturing | 2021 |
| IDO Transport Ltd | Transport & logistics | 2021 |
| Ien-Cuiod Limited | Professional & scientific | 2003 |
| Iequos Group Limited | Information & communication | 2021 |
| Iese C.I.C. | Information & communication | 2011 |
| Iese Innovation Ltd | Information & communication | 2013 |
| Igamingxl Limited | Professional & scientific | 2018 |
| Igboma Associate Ltd | Construction | 2023 |
| Igrid Solutions Ltd | Wholesale & retail | 2014 |
| IHT Trans Ltd | Transport & logistics | 2026 |
| IL Palio Removals Ltd | Transport & logistics | 2024 |
| ILG & Sons Properties Ltd | Real estate | 2024 |
| ILG Properties Ltd | Real estate | 2023 |
| ILG Properties Management Limited | Real estate | 2023 |
| Iliev Logistic Ltd | Transport & logistics | 2019 |
| Illumination Jetwashing Ltd | Administrative & support | 2023 |
| Illumination Properties Ltd | Extraterritorial | 2020 |
| Illumination Utilities Ltd | Transport & logistics | 2025 |
| ILT Consultancy Ltd | Information & communication | 2021 |
| Image Branding Consultancy Limited | Education | 2011 |
| Imaginative Catering Ltd | Hospitality | 2013 |
| Imagine Play (Medway) LLP | | 2025 |
| Imagine Play Ltd | Hospitality | 2024 |
| IMI Maintenance & Service Ltd | Construction | 2026 |
| Immblossoms Limited | Real estate | 2025 |
| Impact Business Consulting Limited | Professional & scientific | 2001 |
| Imperf Consulting Limited | Information & communication | 2009 |
| Imperial Doctors Limited | Health & social care | 2016 |
| Imperial Horizons Limited | Real estate | 2022 |
| Imperium Cosmetics UK Ltd | Wholesale & retail | 2024 |
| Impress IT Limited | Professional & scientific | 1997 |
| Impulsiv Ltd | Professional & scientific | 2019 |
| Impuriti Limited | Manufacturing | 2021 |
| IMS DC Services Limited | Professional & scientific | 2026 |
| IN & OUT Building Services Limited | Construction | 2026 |
| IN & OUT Cleaning Co Limited | Administrative & support | 2025 |
| IN & OUT Lifts Ltd | Professional & scientific | 2020 |
| IN & OUT Property 1 Ltd | Construction | 2026 |
| IN & OUT Property Limited | Real estate | 2025 |
| IN and OUT the Box Ltd | Wholesale & retail | 2023 |
| Inari Distributions Ltd | Other services | 2025 |
| Incartus Development South East Ltd | Construction | 2013 |
| Incasud Group Ltd | Wholesale & retail | 2023 |
| Incorporate Solutions Limited | Information & communication | 2006 |
| Incsol Limited | Information & communication | 2013 |
| Indaluk Ltd | Construction | 2022 |
| Independent Federation for Safeguarding Limited | Other services | 2025 |
| Indiana Jones Limited | Extraterritorial | 2022 |
| Indie Film Rocket Ltd | Professional & scientific | 2020 |
| Indiejude Limited | Administrative & support | 2024 |
| Indratech Network Solutions Ltd | Information & communication | 2018 |
| Industrial Competency Training Limited | Education | 2025 |
| Industrial Flooring (UK) Limited | Construction | 2012 |
| Industrial Gearbox Repairs Limited | Manufacturing | 2024 |
| Ineo Systrans UK Ltd | Professional & scientific | 2022 |
| Infinity Comfort Ltd | Transport & logistics | 2026 |
| Infinity Fitness Ltd | Arts & recreation | 2023 |
| Infinity Networks Limited | Administrative & support | 2002 |
| Information Management Solutions and Services Ltd | Information & communication | 2010 |
| Infoseq Limited | Administrative & support | 2013 |
| Infrafit Ltd | Arts & recreation | 2022 |
| Inked Stitchez Ltd. | Other services | 2017 |
| Inkfinity Print Solutions Ltd | Manufacturing | 2024 |
| Inkie Winkie Ltd | Arts & recreation | 2019 |
| Inload Limited | Transport & logistics | 2022 |
| Innes Property Solutions Ltd | Real estate | 2026 |
| Innovation Flooring & Facilities Ltd | Construction | 2026 |
| Innovation Software Ltd. | Information & communication | 1982 |
| Innovation Workshop Limited | Professional & scientific | 2017 |
| INNOVATION4RECRUITMENT Ltd | Manufacturing | 2024 |