| HY Clutches Ltd | Wholesale & retail | 2011 |
| Hydra Technical Services Limited | Professional & scientific | 1992 |
| Hydro Heat (Kent) Ltd | Construction | 2019 |
| Hyklass Harbour Ltd | Construction | 2022 |
| Hyperium Limited | Professional & scientific | 2003 |
| Hysteria Escape Rooms Limited | Arts & recreation | 2018 |
| HZ Assets Ltd | Real estate | 2020 |
| I Love Cakes by Olga Ursu Ltd | Manufacturing | 2023 |
| I WAS a Sinner Ltd | Professional & scientific | 2024 |
| I.M Incoroporated Ltd | Wholesale & retail | 2024 |
| I.T. Star Electronic Limited | Wholesale & retail | 2020 |
| IAC Delivery Solutions Limited | Transport & logistics | 2023 |
| IAN Brewer Ltd | Construction | 2020 |
| IAN Kemsley Farms Limited | Agriculture & fishing | 1988 |
| IAR Real Estate Ltd | Real estate | 2020 |
| IAS Advisory Services Ltd | Professional & scientific | 2026 |
| Ibar Events Ltd | Hospitality | 2022 |
| IC Construction Kent Limited | Construction | 2023 |
| IC Regeneration Consultants Ltd | Real estate | 2019 |
| Ice Alert Limited | Wholesale & retail | 2004 |
| Icecab Ltd | Transport & logistics | 2026 |
| Iconyx Tattoo Ltd | Other services | 2025 |
| ICS Properties Ltd | Real estate | 2018 |
| Ideas & That Limited | Professional & scientific | 2019 |
| IDEAS2RESULTS Limited | Professional & scientific | 2002 |
| Ideygo Ltd | Administrative & support | 2025 |
| IFG Hire & Sales Ltd | Wholesale & retail | 2022 |
| IFG Properties Ltd | Construction | 2025 |
| IFG UK Holdings Limited | Financial services | 2023 |
| IFG UK Ltd | Financial services | 2022 |
| IFO Systems Ltd | Information & communication | 2025 |
| Iftob Limited | Health & social care | 2014 |
| Ifun UK Ltd | Wholesale & retail | 2018 |
| IG Carpentry and Building Ltd | Construction | 2026 |
| Igri Transport Ltd | Transport & logistics | 2025 |
| Ijeaku Limited | Wholesale & retail | 2025 |
| IK Ecom Ltd | Wholesale & retail | 2024 |
| Ikenna Logistics Limited | Construction | 2013 |
| Ikepo Afrodelight Foods Ltd | Wholesale & retail | 2024 |
| IL MIO Futuro Ltd | Administrative & support | 2017 |
| Ileden Shoot Limited | Agriculture & fishing | 2021 |
| Iljsim Ltd | Transport & logistics | 2025 |
| Illusion Pyrotechnics Limited | Wholesale & retail | 2014 |
| Ilminster Rise Management Company (Clapham) Limited | Households | 2004 |
| IM Drylining Ltd | Construction | 2018 |
| Imaco (UK) Ltd | Professional & scientific | 1998 |
| Imagefix Services Ltd | Other services | 2024 |
| Imajin Solutions Limited | Information & communication | 2013 |
| Immanuel School Multi Academy Trust Limited | Education | 2017 |
| Immundnz Limited | Professional & scientific | 2016 |
| Immunosys Ltd | Professional & scientific | 2012 |
| Impressions Joinery Holdings Limited | Manufacturing | 2016 |
| Impressions Joinery Ltd | Financial services | 2025 |
| Incognito Holdings Limited | Real estate | 2018 |
| Indelible London Ltd. | Administrative & support | 2012 |
| Independent Integrity Solutions Limited | Administrative & support | 2023 |
| Independent Paper PLC | Wholesale & retail | 2000 |
| Independent Paper South Limited | Wholesale & retail | 1993 |
| Independent Social Work- Assessments & Consultancy Services Limited | Health & social care | 2019 |
| Indigo ILP Limited | Manufacturing | 2023 |
| Industrial Cleansing Services Limited | Administrative & support | 2013 |
| Industrial Properties Whitstable Limited | Real estate | 2022 |
| Inese G Ltd | Administrative & support | 2020 |
| Infiniti Real Estate Ltd | Real estate | 2022 |
| Infinity Staffing Limited | Administrative & support | 2020 |
| Infolux Ltd | Information & communication | 2019 |
| Infosec Media Limited | Information & communication | 2024 |
| Ingen Holdings Limited | Real estate | 2025 |
| Inkables Limited | Wholesale & retail | 2015 |
| Inksoft Corporation Limited | Information & communication | 2016 |
| Innmark Limited | Wholesale & retail | 2011 |
| Innovation EYE Clinic Ltd | Health & social care | 2020 |
| Insight Group Services Limited | Financial services | 2024 |
| Inspection Ready AI Ltd | Information & communication | 2026 |
| Inspio Ltd | Financial services | 2022 |
| Inspiramos Limited | Education | 2008 |
| Inspired D&B Constructions Ltd | Construction | 2019 |
| Installways Limited | Construction | 2021 |
| Instill Hope Limited | Health & social care | 2025 |
| Instinctive Events Limited | Administrative & support | 2013 |
| Insurance-Lab UK Limited | Financial services | 2010 |
| Intaspan Limited | Professional & scientific | 1996 |
| Integral Foundations & Groundworks Ltd | Construction | 2023 |
| Integrated Care & Support Solution Ltd | Health & social care | 2026 |
| Integrated Service Solutions Limited | Wholesale & retail | 2012 |
| Intelligent Building Development Limited | Information & communication | 2024 |
| Intelligent Ideas Consulting Limited | Professional & scientific | 2015 |
| Intentional Sparkle Limited | Administrative & support | 2025 |
| Interior Design Feng Shui School Limited | Professional & scientific | 2025 |
| International Projects Ltd | Construction | 2023 |
| Inventive Creations Ltd | Wholesale & retail | 2014 |
| Investment Impact Ltd | Information & communication | 2009 |
| Invicta Boxing Academy CIC | Arts & recreation | 2025 |
| Invicta Corporate Services Limited | Professional & scientific | 2001 |
| Invicta DDP Limited | Hospitality | 2026 |
| Invicta Electronics Limited | Manufacturing | 1997 |
| Invicta Fire Protection Ltd | Construction | 2025 |
| Invicta Security Limited | Administrative & support | 2014 |
| Invicta Systems Limited | Wholesale & retail | 2014 |
| Invicta Training Limited | Education | 2016 |