| Indigo Takeaway Limited | Hospitality | 2026 |
| Indigo Web Consultancy Limited | Professional & scientific | 2020 |
| Indigo Web Systems Ltd | Information & communication | 2020 |
| Indigo Winton Ltd | Hospitality | 2022 |
| Individual Industrial Solutions Ltd | Manufacturing | 2014 |
| Individual Interior Design Limited | Wholesale & retail | 1999 |
| Induk Logistic Ltd | Wholesale & retail | 2026 |
| Induna Consulting Limited | Professional & scientific | 2018 |
| Industrial & Domestic Floor Repairs Limited | Construction | 2010 |
| Industrial Marine Solutions Ltd | Wholesale & retail | 2002 |
| Indygo Refinishing 2022 Limited | Wholesale & retail | 2020 |
| Ineo Partners Ltd | Professional & scientific | 2023 |
| Infinita London Ltd | Wholesale & retail | 2025 |
| Infinity 338 Management Company Limited | Households | 2023 |
| Infinity Motor Group Ltd | Wholesale & retail | 2023 |
| Infinity Office Limited | Professional & scientific | 2016 |
| Inflect Limited | Professional & scientific | 2019 |
| Inform Perform Limited | Professional & scientific | 2019 |
| Information Technology UN Limited | Information & communication | 2001 |
| Infosecace Limited | Education | 2025 |
| Infutures Neurodiversity Coaching Limited | Professional & scientific | 2021 |
| Infyn Limited | Professional & scientific | 2025 |
| Ingenious Solutions Limited | Wholesale & retail | 2023 |
| Ingredients Holdings Limited | Real estate | 2021 |
| Ingredients Media Limited | Manufacturing | 2019 |
| Ingrems Removals Limited | Transport & logistics | 1970 |
| Inimical Limited | Households | 1994 |
| Inkfire Limited | Information & communication | 2023 |
| Inly Investments Ltd | Real estate | 2025 |
| Innate Wellness Ltd. | Health & social care | 2016 |
| Innerspace Kitchens Ltd | Construction | 2022 |
| Innisfree Management Limited | Households | 2005 |
| INNOV8IV Labs Limited | Construction | 2022 |
| INNOV8IV Property Limited | Real estate | 2022 |
| INNOV8IV Technical Solutions Limited | Financial services | 2022 |
| Innova Content Ltd | Education | 2021 |
| Innovacore Ltd | Information & communication | 2011 |
| Innovate Ltd | Administrative & support | 2005 |
| Innovative Hire Limited | Administrative & support | 2017 |
| Innovo Business Solutions Ltd | Information & communication | 2020 |
| INOV8 Solutions Limited | Wholesale & retail | 2022 |
| Inqa Limited | Information & communication | 1995 |
| Insideout Cleaning & Gardening Limited | Administrative & support | 2018 |
| Insider Risk Solutions Ltd | Professional & scientific | 2025 |
| Insight Consultancy UK Limited | Professional & scientific | 1999 |
| Insitu Design Limited | Professional & scientific | 2021 |
| Inspectrixx UK Ltd | Administrative & support | 2013 |
| Inspiration Agency Limited | Professional & scientific | 2023 |
| Inspired Developments Durley Grange Limited | Hospitality | 2024 |
| Inspired Developments Holdings Limited | Financial services | 2020 |
| Inspired Developments Shore Limited | Hospitality | 2023 |
| Inspired Developments South Limited | Construction | 2018 |
| Inspired Developments Tower House Limited | Hospitality | 2021 |
| Inspirededge Consulting Services Limited | Information & communication | 2024 |
| Insta Media Ltd | Professional & scientific | 2020 |
| Insta-Move Limited | Transport & logistics | 2016 |
| Instalabel Limited | Information & communication | 2025 |
| Instep Dance Company | Arts & recreation | 2012 |
| Instyle Kitchens Ltd | Extraterritorial | 2014 |
| Insulation 4 U Ltd | Construction | 2022 |
| Insuppa Trading International Limited | Wholesale & retail | 2011 |
| Insurance and Financial Services Limited | Financial services | 2005 |
| Insurance Specialist Group Ltd. | Financial services | 2018 |
| Insure My Health Ltd | Financial services | 2025 |
| Inteck by Icytech Limited | Wholesale & retail | 2024 |
| Integer Homes Limited | Real estate | 2024 |
| Intego Sun Protection Ltd | Wholesale & retail | 2020 |
| Integrated Supported Living Partnership Ltd | Real estate | 2025 |
| Integrated Transport Management Solutions Ltd | Extraterritorial | 2011 |
| Integration Management Ltd | Information & communication | 1997 |
| INTEGRATION4YOU Ltd | Construction | 2018 |
| Integrative Care Limited | Health & social care | 2015 |
| Integrity Construction South Ltd | Construction | 2023 |
| Intelligent Global Sourcing Limited | Wholesale & retail | 2015 |
| Intelligent Land Limited | Professional & scientific | 2010 |
| Intense Beauty Limited | Other services | 2025 |
| Intently Marketing Limited | Information & communication | 2020 |
| Inter Maintenance & Valeting Services Ltd | Administrative & support | 2016 |
| Inter-Con (UK) Limited | Education | 1999 |
| Intercontinental Capital for Afric Ltd | Professional & scientific | 2024 |
| Intercontinental Capital for Africa Ltd | Financial services | 2021 |
| Interglobal Logistics Limited | Transport & logistics | 2023 |
| Interim Management Resolutions Limited | Professional & scientific | 2004 |
| Interiors by Haroys Limited | Wholesale & retail | 2024 |
| Interiors by Novo Ltd | Professional & scientific | 2019 |
| Intermarket Digital Solutions Ltd | Information & communication | 2023 |
| International Audits Ltd | Professional & scientific | 2012 |
| International Care Network | Other services | 2003 |
| International Centre for Education and Family Strategies Ltd | Professional & scientific | 2024 |
| International Compliance Consulting Limited | Financial services | 2017 |
| International Global Relations Limited | Professional & scientific | 2018 |
| International Marine Consultants Ltd | Professional & scientific | 2019 |
| International Mining Wheels Europe Ltd | Wholesale & retail | 2020 |
| International Push to Talk Ltd | Wholesale & retail | 2016 |
| International Qualified Actuaries Group Limited | Professional & scientific | 2024 |
| International Students Agent Limited | Education | 2019 |
| International Students Services Ltd | Education | 2021 |
| Internet Homepage Ltd | Professional & scientific | 2016 |
| Internet Services (South) Ltd | Hospitality | 1997 |
| Internic Ltd | Information & communication | 2005 |