| Infinity Fire Door Installation Ltd | Construction | 2025 |
| Infinity Inklings Ltd | Professional & scientific | 2025 |
| Infinity Itineraries Ltd | Administrative & support | 2025 |
| Infinity Power Group Limited | Professional & scientific | 2025 |
| Infinity SPV Ltd | Real estate | 2019 |
| Infinix Tech Cloud Limited | Information & communication | 2024 |
| Inflata Stechford Limited | Arts & recreation | 2022 |
| Info Bluetech Limited | Wholesale & retail | 2025 |
| Infolatch Ltd | Professional & scientific | 2023 |
| Inforzone.Com IT Services Ltd | Information & communication | 2025 |
| Infospec Limited | Information & communication | 2019 |
| Infovity Ltd | Information & communication | 2012 |
| Ingegno Ltd | Professional & scientific | 2020 |
| Ingenieur Ltd | Manufacturing | 2000 |
| Ingenious Growth Ltd | Professional & scientific | 2013 |
| Ingiltere Property Management Ltd | Real estate | 2025 |
| Ingleside House Limited | Real estate | 2024 |
| Inglewood Property Management (Didsbury) Limited | Households | 2002 |
| Ingram Creative Developments Limited | Extraterritorial | 2016 |
| Ingram Creative Enterprises Limited | Construction | 2007 |
| Ingram Creative Holdings Limited | Financial services | 2016 |
| Ingress Investments Limited | Real estate | 2017 |
| Inicio Technology Limited | Information & communication | 2022 |
| Iniya Food PVT Ltd | Hospitality | 2025 |
| Injoy Limited | Other services | 2010 |
| INK Solutions Ltd | Other services | 2024 |
| Inkedlab Ltd | Arts & recreation | 2019 |
| Inkilike Ltd | Manufacturing | 2019 |
| Inkmark Operations Limited | Information & communication | 2021 |
| Inland (Southern) Limited | Real estate | 2010 |
| Inmec Limited | Mining & quarrying | 1985 |
| Inner Circle Capital Ltd | Wholesale & retail | 2023 |
| Inner City Ceilings Limited | Construction | 2015 |
| Inner Space Design Company Limited | Construction | 1995 |
| Inno Consulting and Software Solutions Ltd | Information & communication | 2025 |
| Innoson Healthcare Ltd | Health & social care | 2021 |
| Innostark Technologies Limited | Information & communication | 2013 |
| Innovate Couriers Limited | Transport & logistics | 2018 |
| Innovate Generation CIC | Information & communication | 2025 |
| Innovate Generation Hub CIC | Information & communication | 2025 |
| Innovation Air Conditioning and Building Services Limited | Construction | 1997 |
| Innovation Churches Limited | Other services | 2022 |
| Innovation Law Limited | Professional & scientific | 2025 |
| Innovationm Mobile & Web Software Development Agency (UK) Limited | Information & communication | 2020 |
| Innovative Builders LDN Ltd | Manufacturing | 2020 |
| Innovative Investing Limited | Real estate | 2025 |
| Innovative Product Development Desk Limited | Professional & scientific | 2013 |
| Innovative Technologies and Solutions Ltd | Wholesale & retail | 2019 |
| Innovativecare Services Ltd | Health & social care | 2019 |
| Innovexadigital Limited | Information & communication | 2025 |
| Inpact B2B Ltd | Professional & scientific | 2024 |
| Inpad Limited | Real estate | 2015 |
| Input Software Limited | Information & communication | 1996 |
| Inrent Captial Ltd | Real estate | 2024 |
| Insight Future Market Research Ltd | Professional & scientific | 2025 |
| Insight Hive Limited | Information & communication | 2024 |
| Insight PR Ltd | Professional & scientific | 2019 |
| Insignia Clinical Solutions UK Ltd | Professional & scientific | 2016 |
| Inspira Surrey Limited | Professional & scientific | 2025 |
| Inspiration Healthcare Group PLC | Wholesale & retail | 1998 |
| Inspiration Healthcare Limited | Wholesale & retail | 2003 |
| Inspiration Holidays Limited | Administrative & support | 2017 |
| Inspiration Homecare Ltd | Extraterritorial | 2009 |
| Inspirational Cleaning Solitions Limited | Administrative & support | 2009 |
| Inspirationz Ltd | Professional & scientific | 2023 |
| Inspire Advisors Limited | Professional & scientific | 2017 |
| Inspire Financial Services Ltd | Financial services | 2024 |
| Inspire IT Solutions Ltd | Information & communication | 2016 |
| Inspire Media Production Ltd | Information & communication | 2024 |
| Inspire Properties Limited | Households | 2015 |
| Inspired Ascent Ltd | Wholesale & retail | 2020 |
| Inspired Real Life Ltd | Administrative & support | 2023 |
| Inspiring Dads Limited | Professional & scientific | 2011 |
| Instaglow Windows and Doors Ltd | Construction | 2020 |
| Installation and Refurbishment Solutions Limited | Administrative & support | 1995 |
| Installation Ltd | Other services | 2025 |
| Installers Index Ltd | Information & communication | 2023 |
| Instant Rubish & Waste Clearance Ltd | Water & waste | 2016 |
| Instant Shelter Hire Limited | Administrative & support | 2022 |
| Instid Limited | Professional & scientific | 2012 |
| Institute for Cancer Vaccines & Immunotherapy | Health & social care | 1999 |
| Institute of Wellbeing Limited | Health & social care | 2001 |
| Insure a Key Ltd | Construction | 2020 |
| Insurgent Security Ltd | Financial services | 2018 |
| Insyncav Limited | Arts & recreation | 2023 |
| Intaspace Ltd | Other services | 2025 |
| Intec Commercial Limited | Construction | 2019 |
| Integras Technologies Limited | Construction | 2002 |
| Integrated Business Research Systems Ltd | Information & communication | 1990 |
| Integrity Roofing Ltd | Construction | 2025 |
| Integrum Site Services Ltd | Professional & scientific | 2021 |
| Intelligent - Systems.Co.Uk Limited | Information & communication | 1999 |
| Intelligent Membranes Limited | Manufacturing | 2013 |
| Intelligent View Studio Limited | Information & communication | 2017 |
| Intellisense Pro Ltd | Administrative & support | 2017 |
| Intent Care Services Limited | Public administration | 2020 |
| Intentional Psychology Limited | Health & social care | 2024 |
| Inter Ocean Corporation Limited | Real estate | 2000 |
| Intercontinental Literary Agency Limited | Administrative & support | 2009 |
| Interfin Investments Ltd | Professional & scientific | 2013 |