| Induchem (UK) Limited | Wholesale & retail | 2002 |
| Indulge the Collection Ltd | Manufacturing | 2018 |
| Indus Valley Builders Ltd | Construction | 2025 |
| Inet Global Solutions Ltd | Information & communication | 2025 |
| Inet Secure UK Ltd | Information & communication | 2010 |
| Infinio Ltd | Wholesale & retail | 2025 |
| Infinite Purple Ltd | Transport & logistics | 2019 |
| Infinite Security Services Ltd | Financial services | 2018 |
| Infinity 8 Management Limited | Hospitality | 2017 |
| Infinity C Ltd | Other services | 2022 |
| Infinity Drinks Ltd | Hospitality | 2014 |
| Infinity Shoot Services Ltd | Professional & scientific | 2024 |
| Infinity Utilities Solutions Limited | Energy | 2025 |
| Infinityworldofbrands Limited | Wholesale & retail | 2025 |
| Infion Ltd | Wholesale & retail | 2008 |
| Infipro Ltd | Information & communication | 2025 |
| Info Matrix Solutions Ltd | Information & communication | 2023 |
| Info-Bi Services Ltd | Information & communication | 2011 |
| Infoair Limited | Professional & scientific | 2017 |
| Infosabs (UK) Ltd. | Information & communication | 2010 |
| Infosight Ltd | Information & communication | 2013 |
| Infostretch UK Limited | Information & communication | 2013 |
| Infotek Solutions Limited | Information & communication | 2021 |
| Infovault Limited | Construction | 2004 |
| Infovision Technologies Ltd | Information & communication | 2019 |
| Infranox Limited | Information & communication | 2025 |
| Infuse and Nourish Limited | Wholesale & retail | 2026 |
| Ingenious Arch Ltd | Information & communication | 2023 |
| Ingleglen Estate Limited | Households | 1968 |
| Inglewood Nursing Homes Limited | Health & social care | 1999 |
| Inite Music Ltd | Information & communication | 2017 |
| Inizee Ltd | Wholesale & retail | 2025 |
| INK Group Limited | Information & communication | 2026 |
| Inkbrit Publishers Ltd | Information & communication | 2026 |
| Inkspirationz Ltd | Arts & recreation | 2025 |
| Inland Water Engineering Limited | Construction | 2016 |
| Innbeauté Group Ltd | Manufacturing | 2025 |
| Innersightlabs Ltd | Information & communication | 2015 |
| Innervation IT Solutions Ltd | Wholesale & retail | 2025 |
| Innervision Management Limited | Information & communication | 1993 |
| Innicio Ltd | Wholesale & retail | 2016 |
| Innoright Solutions UK Ltd | Information & communication | 2025 |
| Innovaai Tech Ltd | Information & communication | 2026 |
| Innovapulse Ltd | Manufacturing | 2024 |
| Innovasports Ltd | Arts & recreation | 2024 |
| Innovation Blocks Ltd | Information & communication | 2022 |
| Innovation Edge Consultancy Limited | Information & communication | 2023 |
| Innovation Training Solutions Ltd | Information & communication | 2022 |
| Innovations Building Services Ltd | Construction | 2022 |
| Innovative Lines Ltd | Real estate | 2016 |
| Innovative Quality Solutions Limited | Information & communication | 2005 |
| Innovative Systems and Technologies Ltd | Information & communication | 2025 |
| Innoverix Limited | Information & communication | 2025 |
| Innovyt Global Solutions Limited | Information & communication | 2018 |
| Inor Homes Ltd | Real estate | 2026 |
| Inorlo Ltd | Wholesale & retail | 2017 |
| Inotech Ltd | Wholesale & retail | 2025 |
| Inova Stone Limited | Wholesale & retail | 2014 |
| Inras Ltd | Health & social care | 2020 |
| INS Tech Engineering Solutions Limited | Administrative & support | 2009 |
| Inside OUT Alliance CIC | Education | 2025 |
| Insight Virtue Ltd | Information & communication | 2019 |
| Insperix Consulting Limited | Information & communication | 2018 |
| Inspire Sports Activities Academy Limited | Arts & recreation | 2025 |
| Inspired Freight PVT Ltd | Transport & logistics | 2024 |
| Inspirisys Solutions Europe Ltd | Information & communication | 2012 |
| Installer Limited | Manufacturing | 2023 |
| Installer Network Limited | Other services | 2021 |
| Instant ANT Limited | Professional & scientific | 2016 |
| Instant Resourcing Ltd | Professional & scientific | 2023 |
| Instant Services 292 Ltd | Transport & logistics | 2019 |
| Instaputt Ltd | Manufacturing | 2022 |
| Insulation Wire Limited | Construction | 2021 |
| Insured Ltd | Financial services | 2022 |
| INT Biotech Ltd | Professional & scientific | 2023 |
| INT Enterprise Limited | Administrative & support | 2013 |
| Intact Marketing Limited | Professional & scientific | 2013 |
| Intagleo Systems UK Limited | Information & communication | 2007 |
| Intask Ltd | Wholesale & retail | 2017 |
| Integral Property Management Limited | Real estate | 2011 |
| Integrated Fibre Solutions Ltd | Information & communication | 2009 |
| Integrity Consultants (UK) Limited | Professional & scientific | 2013 |
| Integya Ltd | Real estate | 1999 |
| Intellect in Limited | Extraterritorial | 2006 |
| Intelliflow AI Limited | Information & communication | 2026 |
| Intelligent Tracking Management Limited | Professional & scientific | 2025 |
| Interface Fire Protection Ltd | Construction | 2026 |
| Interhub Property Ltd | Real estate | 2020 |
| Interim Expert Services Ltd | Information & communication | 2017 |
| Interior Climate Systems Ltd | Construction | 2008 |
| Interior Impressions Holdings Limited | Financial services | 2022 |
| Interior Impressions Ltd | Construction | 2015 |
| Interiorculture Limited | Administrative & support | 2012 |
| Interiors at the Old Cottage Ltd | Construction | 2026 |
| Interminable Ltd | Real estate | 2017 |
| Internal Fire Solutions Limited | Public administration | 2024 |
| Internal Fleet Purchasing Limited | Administrative & support | 2019 |
| International Coatings Limited | Professional & scientific | 1985 |
| International Committee for the Protection of Civilians Limited | Information & communication | 2026 |
| International Corporation Limited | Administrative & support | 2008 |