| IB Tax & Accounting Ltd | Professional & scientific | 2023 |
| Ibotts Limited | Information & communication | 2014 |
| IBR Property Services Ltd | Construction | 2022 |
| Ibrahim Traders & Associates UK Ltd | Professional & scientific | 2025 |
| IBU Consulting Ltd | Information & communication | 2014 |
| IBU Digital Ltd | Information & communication | 2021 |
| IC Builders Ltd | Construction | 2020 |
| IC Intelligence Limited | Information & communication | 2017 |
| IC Technical Solution Ltd | Construction | 2024 |
| IC Wellness Limited | Health & social care | 2012 |
| Ic.Studios Ltd | Information & communication | 2017 |
| Icab Builders Ltd | Construction | 2018 |
| Icare Optician Limited | Health & social care | 2008 |
| Icarrygo.Com Ltd | Administrative & support | 2021 |
| Icarus Pictures Limited | Information & communication | 2011 |
| ICC Global Ltd | Construction | 2013 |
| ICC Wealth Management Ltd | Financial services | 2019 |
| ICD Decorators Limited | Construction | 2024 |
| Ice Global Holdings Limited | Financial services | 2019 |
| Ice Support Limited | Information & communication | 2007 |
| Iceaction Limited | Wholesale & retail | 1995 |
| Iceni Estates Limited | Administrative & support | 2010 |
| Iceway Bidco Limited | Financial services | 2024 |
| Iceway Topco Limited | Financial services | 2024 |
| Ichim Trans Ltd | Transport & logistics | 2019 |
| Icii Chaii Ltd | Wholesale & retail | 2025 |
| Ickenham Football Club Limited | Arts & recreation | 2018 |
| Ickenham Youth Football Club | Arts & recreation | 2013 |
| ICL & Sons Ltd | Professional & scientific | 2025 |
| Iclick Images Ltd | Wholesale & retail | 2012 |
| Icmd Ltd | Construction | 2022 |
| Icms Services Ltd | Construction | 2021 |
| Icon Dental Group Ltd | Health & social care | 2025 |
| Icon Estates Ltd | Real estate | 2025 |
| Icon Medical Group Ltd | Health & social care | 2025 |
| Icon Steel Doors Ltd | Manufacturing | 2023 |
| Iconic Assets Group Ltd | Real estate | 2026 |
| Iconic Unisex Salon Limited | Other services | 2025 |
| Iconique Dreams Ltd | Arts & recreation | 2019 |
| Iconna Ltd | Real estate | 2011 |
| Iconnect Digital Solutions Ltd | Information & communication | 2018 |
| Iconyx Ltd | Information & communication | 2026 |
| Ict-Innovations Limited | Extraterritorial | 2013 |
| Icustomer Limited | Professional & scientific | 2016 |
| ID Cards Direct Ltd | Wholesale & retail | 2018 |
| ID HR & Recruitment Solutions Limited | Administrative & support | 2024 |
| ID Photoshop Ltd | Other services | 2018 |
| IDA Healthcare Limited | Health & social care | 2014 |
| Idasonic Nanocoating Technologies Limited | Professional & scientific | 2024 |
| Idavc Limited | Professional & scientific | 2025 |
| IDB Sevenoaks Limited | Professional & scientific | 2022 |
| Idbylayla Ltd | Professional & scientific | 2024 |
| Ideal Back Office Solution Ltd | Professional & scientific | 2012 |
| Ideal Cars 4U Ltd | Wholesale & retail | 2020 |
| Ideal London Homes Limited | Construction | 2011 |
| Ideal Solutions Limited | Construction | 2023 |
| Ideal Transporter Ltd | Wholesale & retail | 2020 |
| Idealapp Tech Ltd | Information & communication | 2018 |
| Ideas Capital Ltd | Construction | 2021 |
| Identist Limited | Health & social care | 2017 |
| Idera Condos Ltd | Real estate | 2022 |
| Idera Condos One Ltd | Real estate | 2026 |
| Idera Condos Three Ltd | Real estate | 2025 |
| Idera Condos Two Ltd | Real estate | 2022 |
| Idera Estates Ltd | Information & communication | 2015 |
| Idera Holdings Ltd | Real estate | 2020 |
| Idera Real Estates Ltd | Real estate | 2020 |
| Idevelop Property Ltd | Real estate | 2016 |
| Idevia Limited | Professional & scientific | 2025 |
| Idgam Ltd | Professional & scientific | 2021 |
| Idlak Property Management Limited | Real estate | 2026 |
| IDO Build Ltd | Construction | 2021 |
| IDO Estate Holdings Limited | Hospitality | 2026 |
| Idol Film Production Ltd | Information & communication | 2014 |
| Idola Limited | Professional & scientific | 2023 |
| Idris Overseas Limited | Wholesale & retail | 2017 |
| Idriz Hasanaj Construction Limited | Construction | 2019 |
| IDS Infotech (UK) Limited | Information & communication | 2005 |
| IE Corporation Limited | Real estate | 2024 |
| IE London Ltd | Real estate | 2020 |
| IE Real Estates Ltd | Real estate | 2025 |
| IE: Entertainment Ltd | Information & communication | 2020 |
| IE: Three Limited | Administrative & support | 2007 |
| Iendo Ltd | Health & social care | 2021 |
| Ifinity Limited | Information & communication | 1992 |
| Ifitters Limited | Construction | 2008 |
| IFL Furniture Contracts Limited | Wholesale & retail | 2016 |
| Ifro Limited | Information & communication | 2010 |
| IFT Captures Ltd | Professional & scientific | 2020 |
| IGA Sounds Ltd | Wholesale & retail | 2025 |
| IGA23 Ltd | Construction | 2023 |
| Iglobal Tech Limited | Information & communication | 2024 |
| IGNEOUS2 Capital Limited | Construction | 2024 |
| Ignite A&T Marketing Ltd | Professional & scientific | 2024 |
| Ignite Associates Ltd | Other services | 2015 |
| Ignivia Ltd | Information & communication | 2011 |
| IGO Properties & Developments Ltd | Real estate | 2020 |
| IGR Construction Ltd | Construction | 2019 |
| IGY Transport Ltd | Other services | 2011 |
| IHI Enterprise Limited | Hospitality | 2019 |