| Ikie Solicitors LLP | | 2006 |
| IL Primo (Hayes) Limited | Hospitality | 2026 |
| IL Primo (WW) Limited | Hospitality | 2018 |
| IL Primo Caffe Limited | Hospitality | 2015 |
| Image Studio (Chislehurst-Beaverwood) Limited | Administrative & support | 2012 |
| Imagepost Ltd | Wholesale & retail | 2010 |
| Imaging Medias Limited | Professional & scientific | 2010 |
| Imagymnastics Ltd | Arts & recreation | 2025 |
| IMC Consulting Limited | Professional & scientific | 2024 |
| IME Services Kent Limited | Administrative & support | 2019 |
| Immatty (UK) Ltd | Information & communication | 2016 |
| Immatty Properties Limited | Real estate | 2020 |
| Immavill Ltd | Health & social care | 2022 |
| Immoral London Limited | Wholesale & retail | 2022 |
| Impact Health Limited | Professional & scientific | 2024 |
| Imperial Ductwork Services Holdings Limited | Financial services | 2013 |
| Imperial Ductwork Services Limited | Construction | 1997 |
| Imperial Fire Solutions Limited | Construction | 2020 |
| Imperial Homes Holdings Limited | Extraterritorial | 2017 |
| Imperial Homes London Limited | Extraterritorial | 2017 |
| Imperial Homes Tonbridge Ltd | Construction | 2004 |
| Imperial Hygiene Solutions Limited | Administrative & support | 2020 |
| Imperial Mechanical Consultancy Services Limited | Administrative & support | 2017 |
| Imperial Software Solutions Limited | Extraterritorial | 2008 |
| Império DA Rainha CIC | Education | 2025 |
| IMV Dryliner Ltd | Construction | 2022 |
| IN Safe Hands Management Ltd | Professional & scientific | 2026 |
| Incurable CUT Limited | Information & communication | 2025 |
| Independence Way Ltd | Hospitality | 2016 |
| Independent Homecare Team Limited | Health & social care | 2011 |
| Independent Spanish Restaurant Company (South) Limited | Hospitality | 2019 |
| Indian Gossip Limited | Hospitality | 2025 |
| Infamous Supplies Ltd | Wholesale & retail | 2023 |
| Infection Prevention Group Limited | Manufacturing | 2020 |
| Infinitas Group Ltd | Information & communication | 2021 |
| Infrastructure One Limited | Construction | 2024 |
| Inimi Media Limited | Information & communication | 2025 |
| Inina Nouar Limited | Administrative & support | 2018 |
| Innersculpt Pilates Limited | Arts & recreation | 2023 |
| Inngenii Limited | Professional & scientific | 2014 |
| Innovative NRG Ltd | Professional & scientific | 2021 |
| Innovative Property Management Ltd | Financial services | 2022 |
| INP (UK) Ltd | Manufacturing | 2014 |
| Inside OUT Decorating Services Limited | Construction | 2015 |
| Inspire Community Trust | Manufacturing | 2004 |
| Inspire Medicare Ltd. | Wholesale & retail | 2018 |
| Inspirisk Limited | Professional & scientific | 2018 |
| Instructor Locator Ltd | Administrative & support | 2022 |
| Instyle Developments (London) Limited | Construction | 2018 |
| Instyle Developments Limited | Financial services | 2013 |
| Insurance Management (Hldgs) Limited | Financial services | 1981 |
| Integral Construction (SE) Limited | Administrative & support | 2017 |
| Integral Sponsorship and Experimental Marketing Limited | Professional & scientific | 2012 |
| Integrity Fibre Limited | Administrative & support | 2024 |
| Inter Cargo Surveyors Limited | Professional & scientific | 2011 |
| Inter-Build AID | Other services | 2007 |
| Interaxis Events Limited | Professional & scientific | 2019 |
| Interaxs Global Limited | Administrative & support | 2018 |
| Interior Craft Solutions (UK) Limited | Administrative & support | 2011 |
| Interlink Marketing and Services Limited | Professional & scientific | 1983 |
| International ADM Services Limited | Wholesale & retail | 2019 |
| International Distribution Partners Limited | Professional & scientific | 2024 |
| International Security and Surveillance Limited | Administrative & support | 2013 |
| International Therapy Learning Centre Ltd. | Health & social care | 2025 |
| Internet Computer Bureau Limited | Information & communication | 1996 |
| Intra London Limited | Professional & scientific | 2025 |
| Intrali Limited | Information & communication | 2010 |
| Inventory Force Limited | Administrative & support | 2014 |
| Investaway Ltd | Professional & scientific | 2019 |
| Investella Property Ltd | Real estate | 2024 |
| Invicta Engineering Services Ltd | Professional & scientific | 2022 |
| Invicta Model Rail Limited | Wholesale & retail | 2013 |
| Invictus Development Holdings Limited | Financial services | 2024 |
| Invictus Property Construction Ltd | Construction | 2026 |
| Invremovals Ltd | Transport & logistics | 2019 |
| Ipej Ltd | Administrative & support | 2023 |
| IPL Direct Ltd | Wholesale & retail | 2020 |
| IR Training Assessment Consulting Limited | Other services | 2018 |
| Isaac Automotives Limited | Wholesale & retail | 2022 |
| Isbec Construction Management Ltd | Professional & scientific | 2024 |
| Isco Properties Limited | Real estate | 2001 |
| Isla Stone Restoration Ltd | Manufacturing | 2022 |
| IT Cycle Ltd | Water & waste | 2020 |
| Itcc Holdings Ltd | Other services | 2021 |
| Itfitz.Com Limited | Wholesale & retail | 2000 |
| Itproto Ltd | Information & communication | 2014 |
| Itsm London Limited | Information & communication | 2012 |
| It’S ALL About the Change. Limited | Health & social care | 2025 |
| Ivory Hair Limited | Other services | 2008 |
| IVY League Scholars Ltd | Information & communication | 2017 |
| Iwash Mobile Valeting Ltd | Administrative & support | 2019 |
| J & B Building and Design Limited | Other services | 2015 |
| J & C UK Cleaning Limited | Administrative & support | 2013 |
| J & K Plumbing & Heating Ltd | Construction | 2005 |
| J & R Edwards Ltd | Real estate | 2023 |
| J & R Investment Properties Ltd | Real estate | 2022 |
| J a Cooper Electrics Limited | Construction | 2018 |
| J a Cooper Properties Limited | Real estate | 2016 |
| J a S Electrical Services Limited | Construction | 2011 |
| J a Simmonds Electrical Limited | Construction | 2017 |