| IA Hub UK CIC | Education | 2026 |
| IASERVICES4 Limited | Information & communication | 2025 |
| IB Care Homes Ltd | Health & social care | 2024 |
| IBA Courier Ltd | Transport & logistics | 2024 |
| Ibaad Pathways Ltd | Wholesale & retail | 2024 |
| Ibby Development Limited | Real estate | 2020 |
| Ibeck Consulting Ltd | Information & communication | 2023 |
| Ibentos Media Limited | Information & communication | 2023 |
| IBG 1 Ltd | Energy | 2019 |
| IBG 2 Ltd | Construction | 2019 |
| IBG 4 Limited | Construction | 2020 |
| IBG 5 Ltd | Construction | 2022 |
| IBG 6 Ltd | Construction | 2022 |
| IBG Facilities Management Limited | Construction | 2018 |
| IBG Group Holdings Limited | Financial services | 2017 |
| IBG Group Limited | Financial services | 2020 |
| IBI Construct Ltd | Construction | 2015 |
| IBN Jabal Limited | Education | 2008 |
| IBR Energy Solutions Ltd | Construction | 2025 |
| Ibra Homes Ltd | Financial services | 2024 |
| Ibrahimllari Ltd | Construction | 2025 |
| Ibrandz Ltd | Wholesale & retail | 2018 |
| IC Smiles Ltd | Health & social care | 2025 |
| IC4 Property Limited | Real estate | 2021 |
| Iccd Engineering Ltd | Construction | 2025 |
| Ice LAB Research Ltd | Information & communication | 2025 |
| Ice Scaffolding Ltd | Construction | 2002 |
| Ice Steel Refrigeration Ltd | Manufacturing | 2026 |
| Ice Town Ltd | Manufacturing | 2025 |
| Ice-Clear Ventures Ltd | Health & social care | 2024 |
| Iceberg Internal Audit Solutions Ltd | Professional & scientific | 2019 |
| ICF Installation Solutions Ltd | Construction | 2024 |
| Ichthus Enterprises Limited | Health & social care | 1997 |
| Icon Offices Limited | Real estate | 2016 |
| Icon Traders London Ltd | Wholesale & retail | 2021 |
| Iconic Star Care Ltd | Health & social care | 2019 |
| Iconic Walks Ltd | Administrative & support | 2025 |
| Icontrivo Ltd | Information & communication | 2025 |
| ICS Decorators Limited | Construction | 2016 |
| ICS Design and Build Ltd | Construction | 2021 |
| ICS Investors Ltd | Real estate | 2020 |
| ICU Integrated Security Solutions Ltd | Financial services | 2023 |
| ID4 Group Ltd | Construction | 2025 |
| Ideal Carpentry MD Ltd | Construction | 2024 |
| Ideal Heat & Build Ltd | Construction | 2015 |
| Ideal Lofts Limited | Administrative & support | 2017 |
| Ideal Property Maintenance London Limited | Other services | 2025 |
| Ideal Repairs Domestic Appliances Ltd | Other services | 2026 |
| Idealisland UK Limited | Information & communication | 2024 |
| Idesc Ltd | Construction | 2023 |
| Idgo Card Services Ltd | Other services | 2021 |
| Idgo Ltd. | Other services | 2016 |
| Idrees HR Ltd | Administrative & support | 2024 |
| IDS 315 Group Limited | Construction | 2024 |
| IDS Consultancy Services Limited | Education | 2017 |
| IDS Estates Limited | Real estate | 2017 |
| Ieducate Academy Limited | Education | 2022 |
| Ieducate Centre Limited | Education | 2016 |
| IEE Corporation Limited | Financial services | 2017 |
| IEJ Limited | Health & social care | 2019 |
| Iero-Uk Ltd | Wholesale & retail | 2013 |
| Ifeconsult Limited | Transport & logistics | 2021 |
| Ifepay Services Ltd | Financial services | 2009 |
| Ifire Safety Ltd | Administrative & support | 2025 |
| IFK Consultants Limited | Professional & scientific | 2012 |
| Ifrim Drylining Ltd | Construction | 2025 |
| IFS Currency Limited | Financial services | 2014 |
| IG & Sons Ltd | Construction | 2020 |
| IG Decorating Ltd | Construction | 2017 |
| IG Prime Ltd | Construction | 2020 |
| IG Tyson Ltd | Wholesale & retail | 2018 |
| IG3 Property Investments Ltd | Real estate | 2020 |
| Igate Solutions Limited | Information & communication | 2013 |
| Ign.Cc Ltd | Construction | 2021 |
| Ignite Your Future CIC | Education | 2022 |
| Ignited Suppliers Ltd | Administrative & support | 2016 |
| Igrobrand Limited | Wholesale & retail | 2023 |
| Igrow Ltd | Information & communication | 2022 |
| Iguard Security Services Limited | Administrative & support | 2018 |
| Ihan Ltd | Wholesale & retail | 2026 |
| Iimc-International Investor Market Corporation. Limited | Financial services | 2025 |
| Iiza Portfolio Ltd | Real estate | 2022 |
| IJB Internationals Ltd | Wholesale & retail | 2017 |
| IJI Designs and Innovations Limited | Professional & scientific | 2011 |
| IJY Consultancy Limited | Professional & scientific | 2021 |
| Ikhlas Consultancy Ltd | Professional & scientific | 2022 |
| Ilan Specialist Ltd | Construction | 2025 |
| Ilay Ozan Limited | Wholesale & retail | 2021 |
| Ilcuk Limited | Manufacturing | 2018 |
| Ilerka Ltd | Administrative & support | 2024 |
| Ilford Scaffolding Ltd | Construction | 2022 |
| Ilford Shopfronts Ltd | Construction | 2021 |
| ILG Services Limited | Other services | 2006 |
| Ilgun Limited | Hospitality | 2024 |
| Iliana Pappa Specialist Orthodontic Services Limited | Health & social care | 2012 |
| Ilko DV Ltd | Construction | 2021 |
| ILL Go GET IT Limited | Transport & logistics | 2016 |
| ILL IT Solutions Limited | Extraterritorial | 2012 |
| Illussion Ltd | Information & communication | 2026 |
| Ilpan Limited | Other services | 2017 |