| Impossible Brief Limited | Administrative & support | 2015 |
| Imprsv Technologies Limited | Wholesale & retail | 2026 |
| Imtfx Group Ltd | Information & communication | 2023 |
| IN Dressage Ltd | Wholesale & retail | 2015 |
| IN Rainbows Creative Limited | Professional & scientific | 2025 |
| IN2 Recruitment Ltd | Administrative & support | 2016 |
| IN2 Resourcing Ltd | Administrative & support | 2015 |
| Inav Ventures Ltd | Real estate | 2017 |
| Incaro Limited | Wholesale & retail | 2024 |
| Inch Industry Ltd | Manufacturing | 2022 |
| Inclusive Leadership Coaching Ltd | Professional & scientific | 2025 |
| Inconcept Ltd | Construction | 2016 |
| Incroft Solutions Limited | Information & communication | 2025 |
| Independent Chauffeurs Group Ltd | Transport & logistics | 2024 |
| Independent Engineering Consultant Ltd | Other services | 2015 |
| Independent Rehabilitation Medicine Assessments Limited | Health & social care | 2018 |
| Indian Cuisine (Bromley) Ltd | Hospitality | 2018 |
| Industrial Asset Resources Limited | Professional & scientific | 2015 |
| Industrial Asset Solutions Limited | Financial services | 2008 |
| Infinite Health Ltd | Health & social care | 2012 |
| Infinite Investment Group Limited | Real estate | 2024 |
| Infinity Buying Group Ltd | Wholesale & retail | 2022 |
| Infinity Kitchens Ltd | Construction | 2016 |
| Infinity Painting Serviceuk Ltd | Construction | 2026 |
| Infinitycleaningserviceuk Ltd | Administrative & support | 2024 |
| Influencers 1 Limited | Administrative & support | 2023 |
| Infomed Research & Training Limited | Administrative & support | 2004 |
| Informatics Direct Limited | Information & communication | 2019 |
| Information Horizons Limited | Information & communication | 1990 |
| Infrastructure Management and Engineering Services Limited | Construction | 2006 |
| Infratel Limited | Construction | 2024 |
| Ingleside Close Estate Limited | Real estate | 1996 |
| Inhand London Limited | Information & communication | 2023 |
| Inheritax Limited | Professional & scientific | 2003 |
| Initial Care Homes and Care Services Ltd | Health & social care | 2019 |
| INK23 Finance Ltd | Administrative & support | 2026 |
| Inkline Marketing Limited | Professional & scientific | 2025 |
| Inman Media Services Limited | Information & communication | 2011 |
| Inner-Soul Group Limited | Health & social care | 2016 |
| Innes Lodge RTM Company Limited | Households | 2013 |
| Innjobs Ltd | Administrative & support | 2021 |
| Innocentee & Sons Ltd | Other services | 2024 |
| Innohill Limited | Professional & scientific | 2016 |
| INNOVA-24 Ltd | Real estate | 2024 |
| Innovate Interiors Property Services Ltd | Construction | 2025 |
| Innovative Marketing Solutions Limited | Professional & scientific | 2017 |
| Innovo Labs Limited | Information & communication | 2016 |
| Inscape Projects Ltd | Construction | 2020 |
| Inside & OUT Solutions Ltd | Professional & scientific | 2023 |
| Insight HR Consulting Ltd | Administrative & support | 2025 |
| Inspect Electrical Ltd | Construction | 2020 |
| Inspirational Teaching Limited | Agriculture & fishing | 2018 |
| Inspire Futsal Academy Limited | Arts & recreation | 2015 |
| Inspire Wholsale Ltd | Wholesale & retail | 2025 |
| Inspired Polygons Ltd | Professional & scientific | 2017 |
| Inspired Venues & Events Ltd | Administrative & support | 2025 |
| Inspiring Teaching Ltd | Administrative & support | 2019 |
| Insta Holdings Ltd | Financial services | 2020 |
| Instaflame Property Services Limited | Construction | 2013 |
| Install My Fireplace Limited | Construction | 2014 |
| Installations (Southern) Limited | Real estate | 2011 |
| Instanishan Ltd | Real estate | 2026 |
| Institute of Public Sector Management | Other services | 1982 |
| Integer Picture Company Limited | Arts & recreation | 2014 |
| Integrated Acquisitions & Business Bureau Ltd | Energy | 2025 |
| Integrated Office Solutions Limited | Information & communication | 1997 |
| Integrated Projex Management Ltd | Professional & scientific | 2023 |
| Intelligent Business Finance Ltd | Extraterritorial | 2003 |
| Intelligent FM Limited | Information & communication | 2026 |
| Intelligent Innovations & Iterations Ltd | Information & communication | 2020 |
| Intellingo Ltd | Education | 2025 |
| Inten Limited | Construction | 2008 |
| Inter-Psyche Counselling Training Ltd | Extraterritorial | 2024 |
| Intercultural Network ALB Ltd | Other services | 2024 |
| Interior Smart Solutions Ltd | Construction | 2021 |
| Interlect Services Limited | | 1982 |
| Intermark Medical Innovations Limited | Manufacturing | 1997 |
| International Certified Risk Management Professionals | Administrative & support | 2016 |
| International Conference on Human Rights, Sustainability and Climate Change Ltd | Real estate | 2025 |
| International Numismatic Agency Limited | Manufacturing | 1998 |
| International Real Estate Investor Ltd | Administrative & support | 2016 |
| International Way (Sunbury) Management Company Limited | Households | 2023 |
| International Way Block AA (Sunbury) RTM Company Limited | Real estate | 2020 |
| International Way Block AB (Sunbury) RTM Company Limited | Real estate | 2020 |
| International Way Block AC (Sunbury) RTM Company Limited | Real estate | 2020 |
| International Way Block AD (Sunbury) RTM Company Limited | Real estate | 2021 |
| International Way Block B (Sunbury) RTM Company Limited | Real estate | 2021 |
| International Way Block CD (Sunbury) RTM Company Limited | Real estate | 2020 |
| International Way Block K (Sunbury) RTM Company Limited | Real estate | 2021 |
| Intersol UK Limited | Wholesale & retail | 2022 |
| Interstar Solutions Ltd | Professional & scientific | 2018 |
| Intexo Ltd | Construction | 2025 |
| Intouch Inventory Ltd | Administrative & support | 2020 |
| Intracell Medical UK Limited | Manufacturing | 2018 |
| Intraeuro Limited | Professional & scientific | 1991 |
| Intrepid Universe Limited | Information & communication | 2013 |
| Inventory Clerk Solutions Ltd | Real estate | 2007 |
| Invera Investments Limited | Real estate | 2026 |
| Investco Portfolio Limited | Mining & quarrying | 2017 |
| Investconnect Limited | Wholesale & retail | 2025 |