| IBB Crime Limited | Professional & scientific | 2025 |
| Ibby Plastic Surgery Ltd | Health & social care | 2024 |
| Ibfix Ibfix Ltd | Construction | 2024 |
| Ibuild Property Services Limited | Construction | 2013 |
| Ibzteck Ltd | Information & communication | 2022 |
| IC Projects Ltd | Construction | 2016 |
| Ice Cruise & Excursion Gallery Europe Limited | Administrative & support | 2009 |
| Ickenham Aerials Ltd | Extraterritorial | 2024 |
| Ickenham and District Society of Model Engineers | Arts & recreation | 1999 |
| Ickenham Cafe Bistro Ltd | Hospitality | 2020 |
| Ickenham DRY Cleaners Ltd | Other services | 2025 |
| Ickenham Fish Bar Ltd | Hospitality | 2012 |
| Ickenham Flooring & Designs Limited | Wholesale & retail | 2014 |
| Ickenham Heating Limited | Construction | 2017 |
| Ickenham Pre-School Limited | Education | 2002 |
| Ickenham Sandwich Bar Limited | Hospitality | 2006 |
| Ickenham's Local Ltd | Wholesale & retail | 2025 |
| Icon Constructions Limited | Construction | 2015 |
| Iconic Accounting London Ltd | Professional & scientific | 2020 |
| Icontractor Group Ltd | Wholesale & retail | 2020 |
| Icontractor Services Ltd | Administrative & support | 2022 |
| Icore Stone & Tile Limited | Construction | 2025 |
| ICS Diagnostics Ltd | Wholesale & retail | 2025 |
| Idbit Co Ltd | Information & communication | 2018 |
| IDC Technologies (UK) Limited | Administrative & support | 2014 |
| Ideal Enterprises Limited | Real estate | 1999 |
| Ideal Heat Ltd | Construction | 2024 |
| Ideal Homes Construction Ltd | Construction | 2013 |
| Ideal Housing Limited | Real estate | 2018 |
| Idealux Limited | Real estate | 2005 |
| Iden Ventures Ltd | Information & communication | 2023 |
| Ideotech Ltd | Wholesale & retail | 2020 |
| Idraak Limited | Information & communication | 2021 |
| Idreez Ltd | Wholesale & retail | 2026 |
| IDS Precipice Limited | Arts & recreation | 2024 |
| IEA Consulting Ltd | Information & communication | 2014 |
| Iect Ltd | Construction | 2025 |
| IFA Online Ltd | Wholesale & retail | 2020 |
| Igadget London Limited | Manufacturing | 2016 |
| Ignite Lighting Ltd | Arts & recreation | 2014 |
| Ignytt Ltd | Information & communication | 2020 |
| IGO Tours & Travel Ltd | Transport & logistics | 2020 |
| IGO Tours Ltd | Transport & logistics | 2012 |
| IGR Electrical Ltd | Construction | 2012 |
| IGR Property Investment Ltd | Real estate | 2019 |
| IK Delicious Food Ltd | Hospitality | 2021 |
| Ikigai London Limited | Real estate | 2018 |
| Ikonic Trading Limited | Wholesale & retail | 2025 |
| Iksi Ltd | Hospitality | 2026 |
| Ilapak Limited | Manufacturing | 1970 |
| Ilcare Ltd | Health & social care | 2016 |
| Ilford Fresh Fruits & VEG Ltd | Wholesale & retail | 2014 |
| ILIEV76 Ltd | Transport & logistics | 2023 |
| Illyrian Developments Ltd | Real estate | 2024 |
| Iltis Securities Limited | Financial services | 2022 |
| ILÉ Ltd | Information & communication | 2025 |
| IM. Glass Limited | Construction | 2023 |
| IMA Berlin 6 Limited | Real estate | 2021 |
| IMA Bermuda 9 Limited | Real estate | 2021 |
| IMA Consulting Ltd | Professional & scientific | 2022 |
| IMA CTS Limited | Real estate | 2020 |
| IMA Delhi 11 Limited | Real estate | 2022 |
| IMA Freehold Limited | Administrative & support | 2016 |
| IMA Hammersmith 13 Limited | Real estate | 2022 |
| IMA Holdings Limited | Professional & scientific | 2016 |
| IMA Homes Ltd | Real estate | 2023 |
| IMA Industries Limited | Real estate | 2010 |
| IMA Kassala 2 Limited | Real estate | 2021 |
| IMA London 3 Limited | Real estate | 2021 |
| IMA Madagascar 10 Limited | Real estate | 2022 |
| IMA Mumbai 1 Limited | Real estate | 2021 |
| IMA Property Developments Limited | Administrative & support | 2016 |
| IMA Toronto 7 Limited | Real estate | 2021 |
| IMA Tulear 12 Limited | Real estate | 2022 |
| Imaan Motors Limited | Wholesale & retail | 2017 |
| Imads East Limited | Hospitality | 2025 |
| Image Developers Ltd | Construction | 2018 |
| Imagine Consult Ltd | Professional & scientific | 2024 |
| Imagine Experiences Limited | Administrative & support | 2020 |
| Iman Software Solutions Ltd | Professional & scientific | 2022 |
| Immerse Learning Limited | Information & communication | 2008 |
| Imobile Connect Ltd | Wholesale & retail | 2018 |
| IMP Motors Ltd | Wholesale & retail | 2025 |
| Impact Court Limited | Households | 2003 |
| Impact Web 3 Ltd | Information & communication | 2022 |
| Impala Fine Real Estate Ltd | Construction | 2022 |
| Imperatore B.E. Real Estate Management Ltd | Real estate | 2022 |
| Imperial Homes (Residential Lettings & Sales) Limited | Real estate | 1993 |
| Imperial Homes Worldwide Limited | Real estate | 2000 |
| Imperium Group Limited | Professional & scientific | 2006 |
| Import MED Instruments Ltd | Manufacturing | 2024 |
| Impress Trading Ltd | Wholesale & retail | 2022 |
| Imprint Concrete Driveway Ltd | Construction | 2024 |
| Imprivata UK Limited | Administrative & support | 2013 |
| Improvement Works Ltd | Construction | 2008 |
| Impulse Motors Ltd | Wholesale & retail | 2021 |
| Imraev Properties Ltd | Real estate | 2022 |
| IMS Film Services Limited | Information & communication | 2019 |
| IMV Cars Limited | Transport & logistics | 2018 |
| IN Detail Directory Ltd | Other services | 2014 |