| Infinite Waste Management Ltd | Water & waste | 2022 |
| Infinitesimal Enterprises Limited | Manufacturing | 2015 |
| Infiniti Fibre Limited | Information & communication | 2021 |
| Infinitia Global Limited | Information & communication | 2024 |
| Infinitree Limited | Manufacturing | 2010 |
| Infinity Bidco 1 Limited | Financial services | 2021 |
| Infinity Commercial Cleaning Services Ltd | Administrative & support | 2014 |
| Infinity Electrical Services Ltd | Energy | 2014 |
| Infinity Empire Limited | Wholesale & retail | 2026 |
| Infinity Financials Limited | Financial services | 2015 |
| Infinity Global Consults Ltd | Professional & scientific | 2025 |
| Infinity Gold Ltd | Wholesale & retail | 2025 |
| Infinity Ignis Ltd | Administrative & support | 2025 |
| Infinity INK Limited | Other services | 2019 |
| Infinity International Recruitment Ltd | Administrative & support | 2025 |
| Infinity JWL Ltd | Wholesale & retail | 2022 |
| Infinity Midco Limited | Financial services | 2021 |
| Infinity Motion Ltd | Wholesale & retail | 2016 |
| Infinity Recruitment Consultancy Limited | Other services | 2017 |
| Infinity Sales Limited | Wholesale & retail | 2025 |
| Infinity Systems Engineering Ltd | Professional & scientific | 2019 |
| Infinity Woman Ltd | Wholesale & retail | 2023 |
| Infloe.Io Ltd | Information & communication | 2025 |
| Influence Wireless Limited | Information & communication | 2020 |
| Influencedbyus Limited | Professional & scientific | 2025 |
| Influxdata Operations UK Ltd | Information & communication | 2018 |
| Infobristech Ltd | Other services | 2026 |
| Infocandy Animations Ltd | Professional & scientific | 2016 |
| Infomill (Holdco) Ltd | Professional & scientific | 2013 |
| Infomill Limited | Information & communication | 1996 |
| Inform Consulting Engineers Ltd | Professional & scientific | 2019 |
| Information Experts Ltd | Information & communication | 2019 |
| Infosec Animations Ltd | Extraterritorial | 2024 |
| Infosol Limited | Information & communication | 2012 |
| Infostellar UK Limited | Information & communication | 2019 |
| Infotech Facilities Management Limited | Construction | 2023 |
| Infra Logistics Limited | Arts & recreation | 2010 |
| Inframan Limited | Professional & scientific | 2015 |
| Infraserv Limited | Construction | 2013 |
| Infrastructure and Development Board Limited | Other services | 2023 |
| Infusion Design Limited | Manufacturing | 2015 |
| Infusion Event Management Ltd | Administrative & support | 2007 |
| Infusion Properties Ltd | Real estate | 2021 |
| Ingage IR Limited | Information & communication | 2013 |
| Ingear Diagnostics Limited | Manufacturing | 2013 |
| Ingear Property Services Ltd | Hospitality | 2023 |
| Ingen (UK) Ltd. | Information & communication | 2001 |
| Ingenia Concepts Limited | Extraterritorial | 2014 |
| Ingenia Limited | Wholesale & retail | 2010 |
| Ingenious Inventories Limited | Professional & scientific | 2010 |
| Ingeniousys Limited | Information & communication | 2018 |
| Ingenium Civil Engineering Ltd | Construction | 1997 |
| Ingenium Holdings Ltd | Financial services | 2024 |
| Ingenium Plant Hire Ltd | Administrative & support | 2024 |
| Ingenuity Electrical Solutions Ltd | Construction | 2013 |
| Ingenuity Property Limited | Real estate | 2023 |
| Ingenuity Trade Limited | Construction | 2017 |
| Ingeteam Ltd. | Manufacturing | 2023 |
| Inglebreak Limited | Professional & scientific | 2014 |
| Ingleby Management Co. Limited | Households | 1983 |
| Inglefest CIC | Arts & recreation | 2025 |
| Inglenook Management Limited | Administrative & support | 2006 |
| Inglepark Limited | Manufacturing | 2015 |
| Ingleside Hospitality Limited | Hospitality | 2018 |
| Ingofar Limited | Information & communication | 2023 |
| Ingredients Link Limited | Wholesale & retail | 2007 |
| Ingrid Chauvet Developments Ltd | Construction | 2025 |
| Ingénierie Ltd | Wholesale & retail | 2019 |
| Inhall Ltd | Wholesale & retail | 2023 |
| Inheriting Earth Limited | Professional & scientific | 2018 |
| Inhmd Limited | Health & social care | 2024 |
| Inhope (Bristol) Limited | Health & social care | 1988 |
| Inica Holdings Limited | Information & communication | 2014 |
| Inim Ltd | Wholesale & retail | 2021 |
| Inis Top Company Limited | Financial services | 2021 |
| Init Books Limited | Manufacturing | 2022 |
| Initial Aspiration Ltd | Hospitality | 2022 |
| Initial Recruitment Services Ltd | Administrative & support | 2009 |
| Initialised Limited | Information & communication | 2003 |
| Initsix Software Engineering Ltd | Information & communication | 2004 |
| Iniyan Ltd | Wholesale & retail | 2024 |
| Injectafirebarrier Ltd | Extraterritorial | 2021 |
| Injo Limited | Professional & scientific | 2018 |
| INK Distribution Ltd | Transport & logistics | 2012 |
| INK Junky Tattoo Studio Ltd | Extraterritorial | 2022 |
| Ink-Tec Solutions Ltd | Other services | 2020 |
| Inkbloc Ensemble Ltd | Arts & recreation | 2018 |
| Inklife Tattoo Ltd | Other services | 2020 |
| Inklingroom CIC | Arts & recreation | 2024 |
| Inkon Training Limited | Education | 2021 |
| Inkonhair Clinic Limited | Other services | 2018 |
| Inktatt.Co.Uk Limited | Other services | 2025 |
| Inkwe Studios Ltd | Information & communication | 2026 |
| Inla (Manchester) Limited | Other services | 2011 |
| Inline Automotive Resources Ltd | Wholesale & retail | 2022 |
| Inline Electrical (Bristol) Ltd | Construction | 2013 |
| Inline Signs Limited | Manufacturing | 2016 |
| Inlytics Limited | Information & communication | 2025 |
| Inman & Associates Limited | Financial services | 2010 |
| Inmoment Holdings (UK) Limited | Professional & scientific | 2006 |