| Ichiban UK Limited | Manufacturing | 2013 |
| Icon Assets Ltd | Construction | 2024 |
| Icon Waste Management Ltd | Water & waste | 2026 |
| Icon-Zico Services Limited | Wholesale & retail | 2025 |
| Iconfylab Limited | Wholesale & retail | 2025 |
| Iconic Kitchens Limited | Construction | 2014 |
| Iconpro Limited | Administrative & support | 2013 |
| Icpc Electronics Ltd | Wholesale & retail | 2023 |
| Icsrm Ltd | Education | 2023 |
| ICY Capital Ltd | Professional & scientific | 2025 |
| ID Skins Ltd | Manufacturing | 2024 |
| IDA Neuro Limited | Information & communication | 2024 |
| Idda LAB Ltd | Health & social care | 2025 |
| Ideal Shipping MTB Limited | Transport & logistics | 2025 |
| Ideal Solution (MTB) Ltd | Transport & logistics | 2019 |
| Ideal Solution (Warehousing and Logistics) Limited | Transport & logistics | 2017 |
| IDEAS2GETHER Limited | Professional & scientific | 2022 |
| Ideatoweb Ltd | Information & communication | 2025 |
| Idobras Service Ltd | Construction | 2024 |
| Iebarrett Limited | Information & communication | 2015 |
| IEL Projects Ltd | Professional & scientific | 2024 |
| Ielite Ltd | Wholesale & retail | 2016 |
| Ifnotme-Inclusion-Coaching Ltd | Administrative & support | 2017 |
| IGC Group Ltd | Administrative & support | 2019 |
| Igem London Limited | Wholesale & retail | 2019 |
| Ignis Installations Limited | Construction | 2016 |
| Ignis Property London LLP | | 2015 |
| Ignis Scaling Ltd | Information & communication | 2025 |
| Ignislab Ltd | Information & communication | 2021 |
| Ignite Clarity 1 Ltd | Real estate | 2021 |
| Ignite Clarity 2 Ltd | Real estate | 2022 |
| Ignite Clarity Holdings Ltd | Real estate | 2021 |
| IGP Specialty LLC Ltd | Financial services | 2025 |
| IGS Property Ltd | Real estate | 2016 |
| IH Capital & Research Ltd | Professional & scientific | 2025 |
| Ihenriques Ltd | Information & communication | 2026 |
| Ihma Prof Serv Ltd | Professional & scientific | 2017 |
| Ihsaan Group Limited | Information & communication | 2021 |
| IJB Contractors Ltd | Construction | 2013 |
| IJC Property Group Ltd | Real estate | 2019 |
| Ijem Consulting Limited | Professional & scientific | 2021 |
| Ikbal Global Limited | Hospitality | 2022 |
| Ikkystickytreats Ltd | Manufacturing | 2023 |
| ILE Waffi Ltd | Information & communication | 2026 |
| Ilevel Ltd | Wholesale & retail | 2013 |
| Ilham Servers Limited | Information & communication | 2025 |
| Illumens LLP | | 2025 |
| Illumina Engineers Limited | Professional & scientific | 1998 |
| Illuminai Ltd | Information & communication | 2025 |
| Illumiraki Limited | Wholesale & retail | 2021 |
| Ilmm Limited | Professional & scientific | 2017 |
| ILP Protection (NOC) Limited | Extraterritorial | 2008 |
| Ilumi Technologies Ltd | Information & communication | 2025 |
| IM13 Ltd | Wholesale & retail | 2025 |
| Imagenation Interior Design Ltd | Professional & scientific | 2024 |
| Imaginari Theatre CIC | Administrative & support | 2023 |
| Imanuel Construction Limited | Construction | 2019 |
| Imazin Digital Agency Ltd | Information & communication | 2025 |
| Imek Beauty Ltd | Wholesale & retail | 2025 |
| Imitation Fishing Ltd | Wholesale & retail | 2025 |
| Immaculate Gardens and Ground Care Limited | Administrative & support | 2017 |
| Immersive Maths Ltd | Education | 2025 |
| Immersive Network Ltd | Other services | 2016 |
| Immo Property Investment Ltd | Real estate | 2021 |
| Imodex Consulting Limited | Manufacturing | 2026 |
| Imomi Limited | Wholesale & retail | 2024 |
| Impact Community Business Consulting Ltd | Professional & scientific | 2025 |
| Impact Engine Limited | Information & communication | 2024 |
| Impact Guru Ltd | Professional & scientific | 2025 |
| Impact Laundry & Cleaning Ltd. | Administrative & support | 2017 |
| Impact Service Solutions Limited | Information & communication | 2020 |
| Impact Solution Group Limited | Information & communication | 2024 |
| Impactful Property Solutions Ltd | Real estate | 2022 |
| Imperial Academy International Consulting Limited | Education | 2024 |
| Imperial Gifts Ltd | Manufacturing | 2025 |
| Imperial Homelin Ltd | Information & communication | 2025 |
| Imperial Property Management Group Ltd | Construction | 2022 |
| Imperial Trading & Services Limited | Wholesale & retail | 2017 |
| Imperius Group UK Limited | Financial services | 2019 |
| Impossible Question Ltd | Information & communication | 2025 |
| Impress Express Signs & Graphics Limited | Manufacturing | 2014 |
| Impresso Ltd | Wholesale & retail | 2020 |
| Imprint Event Group Ltd | Administrative & support | 2026 |
| Impruv Your Life Ltd | Wholesale & retail | 2017 |
| Impuritee Merchandise Ltd | Wholesale & retail | 2025 |
| IMS Travels Ltd | Administrative & support | 2018 |
| IMW Consulting Limited | Financial services | 2018 |
| IN Brickwork Ltd | Construction | 2010 |
| IN Good Faith Limited | Professional & scientific | 2017 |
| IN Sight Media International Ltd | Arts & recreation | 2023 |
| IN Tents Effects Ltd | Administrative & support | 2018 |
| In.Fame 1 Limited | Manufacturing | 2025 |
| IN4 Ltd | Professional & scientific | 2023 |
| Inash Ltd | Construction | 2021 |
| Incavation Ltd | Manufacturing | 2025 |
| Incdot Technologies Limited | Information & communication | 2013 |
| Incentive Scope Limited | Wholesale & retail | 2024 |
| Inclusive Hiring Works Ltd | Administrative & support | 2024 |
| Inclusive Tech Consulting Ltd | Information & communication | 2023 |
| Inco Ventures Ltd | Information & communication | 2022 |