| Insight Occupational Health Limited | Health & social care | 2005 |
| Insight Probuild Ltd | Construction | 2022 |
| Insight Psychology Services Limited | Professional & scientific | 2023 |
| Insight Solutions Group Holdings Limited | Professional & scientific | 2005 |
| Insight Solutions GRP Recruitment Ltd | Administrative & support | 2003 |
| Inspect a Home UK Ltd | Other services | 2025 |
| Inspire and Coach Ltd | Education | 2024 |
| Inspire Consult Limited | Professional & scientific | 2018 |
| Inspire Media Ltd | Wholesale & retail | 2021 |
| Inspire Mediax Limited | Wholesale & retail | 2019 |
| Inspire Montessori Schools Ltd | Education | 2017 |
| Inspire Studies Limited | Education | 2017 |
| Inspired Clean Limited | Administrative & support | 2012 |
| Inspiring Conversations Limited | Professional & scientific | 2015 |
| Instant Karma Retail Ltd | Wholesale & retail | 2013 |
| Instant Karma Store Limited | Wholesale & retail | 2020 |
| Instik Ltd | Professional & scientific | 2025 |
| Insure Assure Ltd | Financial services | 2023 |
| Inswood Ltd | Information & communication | 2012 |
| Insync Creations Limited | Information & communication | 2010 |
| Int-Trade Global Ltd | Wholesale & retail | 2010 |
| Intech-Digital Limited | Other services | 2005 |
| Integ Capital Limited | Professional & scientific | 2020 |
| Integra Software Services Private Limited | Manufacturing | 2004 |
| Integrated Control Framework Consulting Limited | Administrative & support | 2020 |
| Intellectual Worldwide Limited | Information & communication | 2008 |
| Intellico Consulting Ltd | Information & communication | 2024 |
| Intelligence Exchange Networks Limited | Professional & scientific | 1994 |
| Intelligent Finals Ltd | Education | 2019 |
| Intelstack Ltd. | Extraterritorial | 2025 |
| Intense Cleaning Services Ltd | Administrative & support | 2023 |
| Intense Property Management Ltd | Water & waste | 2024 |
| Interads E Communications Limited | Information & communication | 2005 |
| Intercontinental Food & Wine Ltd | Wholesale & retail | 2011 |
| Intermetals Trading Limited | Professional & scientific | 2011 |
| International Krafts Limited | Wholesale & retail | 2019 |
| International Management Answers (IMA) Ltd | Administrative & support | 2003 |
| Intertrade (UK) Limited & Co | | 1988 |
| Intuitive Academy Limited | Education | 2022 |
| Inventerprise Limited | Administrative & support | 2023 |
| Invento Solutions Limited | Information & communication | 2021 |
| Inves Capital Ltd | Real estate | 2016 |
| Invest-Alfa Ltd | Wholesale & retail | 2019 |
| INVESTMENT4HOME Limited | Real estate | 2024 |
| Investors Mortgage Company Limted | | 1991 |
| Investserv Ltd | Professional & scientific | 2013 |
| Invito Capital Limited | Financial services | 2014 |
| Ioptical Ltd | Health & social care | 2012 |
| Ioptics Ltd | Health & social care | 2017 |
| IOU Consulting Ltd | Professional & scientific | 2011 |
| IP Door Entry Ltd | Wholesale & retail | 2020 |
| Ipbackbone Limited | Information & communication | 2010 |
| Irfan Muzaffar Ltd | Education | 2012 |
| Iris Consulting (UK) Limited | Professional & scientific | 2000 |
| IRM UK Strategic IT Training Limited | Administrative & support | 1999 |
| Ironwood Installations Limited | Construction | 2025 |
| ISG Reparo Investors Group Limited | Professional & scientific | 2004 |
| Isha Mehta Limited | Professional & scientific | 2025 |
| Isha's Locum Services Limited | Manufacturing | 2020 |
| Ishaan Property Limited | Real estate | 2018 |
| Ishisoft Solutions Ltd | Information & communication | 2023 |
| Ishtiaque Corporation Ltd | Professional & scientific | 2014 |
| Isil Consulting Limited | Information & communication | 2015 |
| Iska Estates Limited | Real estate | 2021 |
| Island Litho Limited | Manufacturing | 1998 |
| ISO Dynamics Limited | Information & communication | 2013 |
| Istarway Travel Limited | Administrative & support | 2015 |
| Istrategies Limited | Information & communication | 2020 |
| Isway Limited | Other services | 2015 |
| Itechnology-Uk Limited | Information & communication | 2019 |
| Itechzone Limited | Wholesale & retail | 2017 |
| Itisha Ltd | Information & communication | 2016 |
| Itkan International Ltd | Administrative & support | 2021 |
| ITL Technologies Ltd | Information & communication | 2013 |
| Itree Solutions Limited | Wholesale & retail | 2017 |
| Itsworthmore Limited | Information & communication | 2025 |
| Itsy Dent Ltd | Administrative & support | 2024 |
| Ittaieconature Ltd | Manufacturing | 2025 |
| ITX Project Services Ltd | Information & communication | 2023 |
| It’S Electric Ltd | Wholesale & retail | 2025 |
| Iusartium Consultancy Limited | Professional & scientific | 2012 |
| Ivap Solutions Ltd. | Information & communication | 2012 |
| Ivolve Ltd | Administrative & support | 2017 |
| Ivolve Properties Ltd | Real estate | 2019 |
| Ivory Bricks Limited | Real estate | 2024 |
| IVY Tiger Limited | Administrative & support | 2006 |
| Iwantleads Ltd | Information & communication | 2025 |
| Iweco Limited | Wholesale & retail | 2017 |
| Izzahuk Technical Support Limited | Information & communication | 2016 |
| J & B Wood Lane Limited | Real estate | 2021 |
| J & N Property Investments Ltd | Real estate | 2024 |
| J & R Kiosk Limited | Wholesale & retail | 2011 |
| J a Jameson Ltd | Real estate | 2022 |
| J and B Hardware Limited | Wholesale & retail | 2009 |
| J Apps Consulting Limited | Administrative & support | 2012 |
| J B Support Limited | Administrative & support | 2011 |
| J DEE Limited | Administrative & support | 2021 |
| J E Williamson Limited | Wholesale & retail | 2011 |
| J Goodman Accounting Services Limited | Professional & scientific | 2007 |
| J Hadi Enterprises Ltd | Real estate | 2025 |