| Infinity Realty Group Ltd | Real estate | 2026 |
| Influensaas Limited | Information & communication | 2025 |
| Influx Electrics Limited | Construction | 2024 |
| Infocomm Limited | Information & communication | 2014 |
| Infoit Ltd | Information & communication | 2023 |
| Infojet Ltd | Health & social care | 2021 |
| Inforce Softtech Ltd | Information & communication | 2022 |
| Information & Telecommunications Solutions Limited | Information & communication | 1999 |
| Informationstream Ltd | Information & communication | 2016 |
| Infostorm Limited | Information & communication | 2015 |
| Infrastruct CE Ltd | Professional & scientific | 2019 |
| Infrastructure Tech Ltd | Information & communication | 2014 |
| Infynix Technologies Ltd | Information & communication | 2025 |
| Ingenious Ideas Limited | Professional & scientific | 2010 |
| Inha Services Ltd | Hospitality | 2019 |
| INK and Form Ltd | Wholesale & retail | 2026 |
| INK21 Tattoo Ltd | Arts & recreation | 2023 |
| Inkcommercial Ltd | Professional & scientific | 2023 |
| Inkerman Building & Roofing Limited | Construction | 2002 |
| Inkfinity Printing Ltd | Manufacturing | 2026 |
| Inkjet Service Ltd | Manufacturing | 2009 |
| Inlet Properties Limited | Real estate | 1988 |
| Innaya Limited | Wholesale & retail | 2017 |
| Inneed Cloud Ltd | Extraterritorial | 2025 |
| Inner EYE Vision Photography Ltd | Information & communication | 2018 |
| Inner Healer 4D Ltd | Arts & recreation | 2021 |
| Innoedu Ltd | Education | 2024 |
| Innosoft Ventures Limited | Wholesale & retail | 2023 |
| Innouk Ltd | Professional & scientific | 2022 |
| Innova Healthcare UK Ltd | Health & social care | 2016 |
| Innovara Consulting LLP | | 2024 |
| Innovate to Success Limited | Professional & scientific | 2016 |
| Innovation Power Services Ltd | Construction | 2023 |
| Innovative Generation Limited | Information & communication | 2016 |
| Innovexia Ltd | Information & communication | 2024 |
| Innovibe Services Ltd | Information & communication | 2025 |
| Innpulse Ltd | Arts & recreation | 2025 |
| Innvigorate Limited | Hospitality | 2024 |
| Innvigorate OS Limited | Hospitality | 2024 |
| Inova Kitchens Limited | Wholesale & retail | 2014 |
| Inovexia Digital Ltd | Information & communication | 2021 |
| Inpiste Ltd | Arts & recreation | 2025 |
| Inpra UK Limited | Other services | 2011 |
| Input Trans Ltd | Transport & logistics | 2016 |
| Insaan Arts CIC | Education | 2025 |
| Insari Enterprise Ltd | Wholesale & retail | 2021 |
| Insenity Ltd | Education | 2025 |
| Inside 1 Ltd | Wholesale & retail | 2026 |
| Insight Therapies Ltd | Education | 2024 |
| Inspiration by S&J Ltd | Transport & logistics | 2021 |
| Inspiration Care Group Limited | Health & social care | 2022 |
| Inspiration Logistics Limited | Wholesale & retail | 2024 |
| Inspiration Music Academy Ltd | Arts & recreation | 2026 |
| Inspire & Aspire Ltd | Education | 2018 |
| Inspire Autocare UK Ltd | Wholesale & retail | 2026 |
| Inspire Care & Support Ltd | Health & social care | 2023 |
| Inspire Education Resourcing Specialist Limited | Administrative & support | 2012 |
| Inspire Global Limited | Information & communication | 2026 |
| Inspire IT Consultants Ltd | Information & communication | 2025 |
| Inspire Recruitment Consultants Limited | Administrative & support | 2023 |
| Inspire Security Services Limited | Administrative & support | 2023 |
| Inspired Abodes Properties Limited | Construction | 2019 |
| Inspired Solutions Property Management Ltd | Households | 2020 |
| Insta Medi Care Solutions Limited | Administrative & support | 2021 |
| Insta Property Services Ltd | Construction | 2022 |
| Instacourier Ltd | Transport & logistics | 2025 |
| Instant Construction Services Limited | Construction | 2022 |
| Instant EPC Ltd | Professional & scientific | 2022 |
| Instant Estates Limited | Real estate | 2025 |
| Instant Letting & Estates Ltd | Real estate | 2022 |
| Instant Lettings Limited | Real estate | 2022 |
| Instant Meds Healthcare Ltd | Wholesale & retail | 2024 |
| Instant Move Limited | Real estate | 2019 |
| Instant Offer Property Solutions Ltd | Real estate | 2025 |
| Instant Security Limited | Administrative & support | 2015 |
| Instant Shakes Ltd | Hospitality | 2021 |
| Instant Taxi Limited | Transport & logistics | 2025 |
| Instantaneous World Ltd | Wholesale & retail | 2021 |
| Instinct Traders Ltd | Wholesale & retail | 2023 |
| Integra Facilities Management Limited | Wholesale & retail | 2026 |
| Integrapro Systems Ltd | Construction | 2025 |
| Integrated Property Estate Solutions Ltd | Construction | 2023 |
| Integrated Property Investments Ltd. | Construction | 2002 |
| Integrated Sustainable Enterprise Ltd | Professional & scientific | 2024 |
| Integrity Autos Limited | Wholesale & retail | 2014 |
| Integrity Healthcare Services Ltd | Administrative & support | 2017 |
| Integrity Mediation Solutions Limited | Professional & scientific | 2023 |
| Integrity Projects Limited | Professional & scientific | 2007 |
| Intelx Ltd | Administrative & support | 2018 |
| Intense Aroma Fragrances Ltd | Manufacturing | 2024 |
| Intent Layer Limited | Information & communication | 2026 |
| Intentional Consulting Ltd | Information & communication | 2016 |
| Inter Safe Roofing Ltd | Construction | 2026 |
| Inter Service Intelligence Security Ltd | Transport & logistics | 2020 |
| Intercontinental Foods(Uk) Ltd | Wholesale & retail | 2018 |
| Intercruises Shoreside & Port Services UK Limited | Administrative & support | 2006 |
| Intercruises Shorex Services UK Limited | Administrative & support | 2025 |
| Interior Ideas Ltd | Wholesale & retail | 2024 |
| Interior Options Holdings Limited | Financial services | 2021 |
| Interior Options Limited | Construction | 1983 |