| ID Neurocare Limited | Health & social care | 2014 |
| ID Projects Cheshire Limited | Construction | 2019 |
| Id-I Print Limited | Manufacturing | 2019 |
| IDD Management Limited | Financial services | 2012 |
| Idencia Limited | Other services | 2003 |
| Identified Services Limited | Construction | 2017 |
| Identity Incentives Limited | Administrative & support | 2011 |
| IDETECT365 Ltd | Manufacturing | 2026 |
| IEX Holdings Limited | Financial services | 2025 |
| IGF Property Limited | Construction | 2025 |
| Ihasco Ltd | Information & communication | 2007 |
| Iidy Ltd | Professional & scientific | 2021 |
| IJ Health Limited | Health & social care | 2019 |
| IJT Digital Limited | Professional & scientific | 2023 |
| Ikons Store UK Ltd | Wholesale & retail | 2020 |
| Ilkley Surgical Limited | Health & social care | 2021 |
| Illuminaire Property Group Ltd | Real estate | 2020 |
| Illustrare Limited | Professional & scientific | 2025 |
| Imagine Systems Ltd | Information & communication | 2025 |
| Imagineering Global LLP | | 2018 |
| Imali Holdings Limited | Other services | 2022 |
| Imass Ltd | Professional & scientific | 2025 |
| IMK Medical Ltd | Health & social care | 2025 |
| Immunokey Ltd | Professional & scientific | 2024 |
| Impact Servco Property Ltd | Real estate | 2025 |
| Implant & Aesthetic Academy UK Limited | Education | 2022 |
| IN the Lakes Ltd | Real estate | 2023 |
| In-Toto Kitchens Limited | Manufacturing | 2021 |
| In-Toto Kitchens UK Limited | Manufacturing | 2021 |
| Incotec Solutions Limited | Information & communication | 2004 |
| Independence Capital I Limited | Financial services | 2021 |
| Independence Capital II Limited | Professional & scientific | 2022 |
| Independence Capital III Limited | Professional & scientific | 2022 |
| Independence Capital IV Limited | Information & communication | 2023 |
| Independence Capital Limited | Professional & scientific | 2019 |
| Independence Debt Advisory Limited | Professional & scientific | 2022 |
| Independence Exits Limited | Professional & scientific | 2022 |
| Independence Holdings Limited | Financial services | 2023 |
| Independence Properties Limited | Real estate | 2022 |
| Indequip Limited | Extraterritorial | 2016 |
| India Procurement Ltd | Professional & scientific | 2022 |
| India Supply Chain Ltd | Professional & scientific | 2022 |
| Indish Deliveries Ltd | Hospitality | 2024 |
| Indish Express Wilmslow Ltd | Hospitality | 2023 |
| Indish Paddock Ltd | Hospitality | 2023 |
| Indosys Limited | Professional & scientific | 2007 |
| Indra Consultancy Ltd | Professional & scientific | 2020 |
| Industrial Scientific Holdings UK Ltd | Financial services | 2016 |
| Industrial Scientific UK Ltd | Manufacturing | 2001 |
| Infin-It Business Solutions Ltd | Information & communication | 2018 |
| Influential Accounting Ltd | Professional & scientific | 2020 |
| Infoassurax Ltd | Administrative & support | 2024 |
| Initforthe Ltd | Information & communication | 2004 |
| Initium Capital Ltd | Real estate | 2022 |
| Initium Group Ltd | Professional & scientific | 2019 |
| INK and Toner World (Wilmslow) Ltd | Wholesale & retail | 2015 |
| Inn the Lakes LLP | | 2023 |
| Innervision Software Limited | Information & communication | 2013 |
| Innofund Consulting Limited | Professional & scientific | 2021 |
| Innova Bathrooms Limited | Manufacturing | 2008 |
| Innova Bedrooms Limited | Manufacturing | 2008 |
| Innova Creations Limited | Manufacturing | 2022 |
| Innova Hotels Limited | Hospitality | 2022 |
| Innova Kitchens Limited | Manufacturing | 2008 |
| Innova Leisure Limited | Transport & logistics | 2004 |
| Innova Projects Ltd | Construction | 2019 |
| Innova Red Limited | Wholesale & retail | 2025 |
| Innove Ltd | Professional & scientific | 2001 |
| INOV8 Medical Ltd | Manufacturing | 2013 |
| Insider Design Ltd | Professional & scientific | 2020 |
| Inspire Developments NW Ltd | Real estate | 2025 |
| Inspired by Naples Limited | Hospitality | 2023 |
| Inspired Media Management Ltd | Administrative & support | 2021 |
| Intact Electrical Limited | Construction | 2016 |
| Integral Legal Costs Limited | Professional & scientific | 2020 |
| Integrated Air Filtration Limited | Manufacturing | 2020 |
| Integrated Air Services Ltd | Professional & scientific | 2021 |
| Integrated Air Systems Limited | Manufacturing | 2002 |
| Integrated Software Solutions Limited | Administrative & support | 2008 |
| Integrated Systems 2020 Limited | Professional & scientific | 2019 |
| Integrated Systems 2025 EOT Limited | Financial services | 2025 |
| Intellidraw Ltd | Construction | 2011 |
| Intelligent Metering Ltd | Information & communication | 2011 |
| Intellioffice Ltd. | Information & communication | 2016 |
| Intentional Education Group Limited | Education | 2024 |
| International Developments Group Ltd | Real estate | 2022 |
| Interskill Learning Services Limited | Wholesale & retail | 2021 |
| Introcap Ltd | Professional & scientific | 2024 |
| Introstream Limited | Professional & scientific | 2016 |
| Intuitive Healthcare Limited | Health & social care | 2021 |
| Inubo Trading Ltd | Wholesale & retail | 2013 |
| Investimenti Ltd | Real estate | 2017 |
| Investique Ltd | Real estate | 2014 |
| Invite Limited | Information & communication | 2013 |
| Inzura Ltd | Information & communication | 2010 |
| Ioda Limited | Professional & scientific | 1997 |
| IP Multihome Limited | Information & communication | 2010 |
| IPD Properties Ltd | Professional & scientific | 2011 |
| Ipilates Limited | Wholesale & retail | 2009 |
| Iprint Solutions (UK) Limited | Manufacturing | 2013 |