| Intercharm Limited | Other services | 2014 |
| Interchem Point (UK) Limited | Wholesale & retail | 2025 |
| Intercity Build (UK) Limited | Construction | 2011 |
| Interconnect Direct Limited | Information & communication | 2000 |
| Intercorporation Ltd | Wholesale & retail | 1998 |
| Interculture CIC | Administrative & support | 2016 |
| Interfishnet Ltd | Information & communication | 2012 |
| Interfixx Ltd | Construction | 2018 |
| Interholdings (SW) Limited | Real estate | 2016 |
| Interim Business Services Limited | Administrative & support | 2010 |
| Interim Construction Ltd | Construction | 2022 |
| Interim Management Partners | | 1995 |
| Interim Resourcing Limited | Professional & scientific | 2008 |
| Interior Connect Limited | Wholesale & retail | 2019 |
| Interlec Services (Bristol) Limited | Construction | 1990 |
| Interloop Autos Ltd | Wholesale & retail | 2024 |
| Interlude Coffee Ltd | Hospitality | 2023 |
| Intermech Building Services Limited | Construction | 2023 |
| Intermech Limited | Energy | 2015 |
| Intermediate Care Limited | Professional & scientific | 2001 |
| Internal Maintenance Services Ltd | Construction | 2012 |
| Internal Plastering Finishes Ltd | Construction | 2007 |
| Internal Visions Limited | Health & social care | 2023 |
| International Assets & Resources Limited | Real estate | 2000 |
| International Balloon Fiestas CIC | Administrative & support | 2025 |
| International Certification Services Limited | Administrative & support | 1998 |
| International Children's Palliative Care Network | Other services | 2011 |
| International College of Safety and Security Ltd | Extraterritorial | 2026 |
| International Commercial Management Consultants Limited | Professional & scientific | 2016 |
| International Design Group Limited | Professional & scientific | 2008 |
| International Driving School Ltd | Education | 2020 |
| International Dzogchen Community of Kunselling | Other services | 1990 |
| International Education Systems Limited | Education | 1991 |
| International Federation of Hydrographic Societies | Information & communication | 1982 |
| International Federation of Training and Development Organisations Limited(The) | Other services | 1984 |
| International Fine Art Conservation Studios Limited | Arts & recreation | 2016 |
| International Generators Ltd | Wholesale & retail | 2018 |
| International Golf Design Limited | Professional & scientific | 2007 |
| International House Bristol Ltd | Education | 2003 |
| International Kempo Association | Arts & recreation | 2015 |
| International Link Limited | Public administration | 2025 |
| International Marketing Alliance Limited | Professional & scientific | 2015 |
| International Medication Systems (U.K.) Limited | Manufacturing | 1975 |
| International Organisation of Economic Development (Ioed) Ltd | Other services | 2025 |
| International Peace and Prosperity Mission Limited | Administrative & support | 2020 |
| International Resource and Compliance LLP | | 2020 |
| International Scouting Ltd | Professional & scientific | 2018 |
| International Supply Solutions Ltd | Wholesale & retail | 2022 |
| International Teachers Ltd | Education | 2024 |
| International Wool Harvesters CIC | Agriculture & fishing | 2024 |
| Internet Group Ltd | Financial services | 2021 |
| Internet Ltd | Information & communication | 2017 |
| Internet Videocommunications Holdings Limited | Information & communication | 2010 |
| Internet Videocommunications Limited | Information & communication | 1985 |
| Internetscape Ltd | Wholesale & retail | 2013 |
| Interoperability Health (UK) Limited | Information & communication | 2018 |
| Interpres Topco Limited | Financial services | 2021 |
| Interslice Information Solutions Limited | Other services | 2022 |
| Interstate Media Limited | Information & communication | 2012 |
| Interval Films Ltd | Information & communication | 2010 |
| Intervenor Healthcare Limited | Health & social care | 2018 |
| Interweb Solutions Limited | Information & communication | 2000 |
| Inthelittlewood Limited | Information & communication | 2012 |
| Inti Baby Ltd | Wholesale & retail | 2026 |
| Intitu Limited | Information & communication | 2019 |
| Intmem Group Ltd | Financial services | 2024 |
| Intnts Ltd | Manufacturing | 2025 |
| Intoheat (Holdings) Limited | Construction | 2012 |
| Intoheat Limited | Construction | 1986 |
| Intradiem UK Limited | Information & communication | 2021 |
| Intradynamics Limited | Professional & scientific | 1994 |
| Intramania Software Ltd | Information & communication | 2017 |
| Intrasecure Ltd | Administrative & support | 2014 |
| Intrepid Outdoors Limited | Wholesale & retail | 2018 |
| Intrepid-X Mission Solutions Ltd | Information & communication | 2024 |
| Intrinsic Voices CIC | Education | 2025 |
| Intrinzic Ltd | Wholesale & retail | 2022 |
| Intu Clothing Ltd | Wholesale & retail | 2024 |
| Intueor Consulting Limited | Professional & scientific | 2011 |
| Intuitive Holding Limited | Information & communication | 2012 |
| Intuitive Limited | Information & communication | 2003 |
| Intuitive Software Design Limited | Information & communication | 2001 |
| INU Creative Ltd | Other services | 2026 |
| Inume Consulting Ltd | Information & communication | 2024 |
| Invade International Limited | Administrative & support | 1998 |
| Invatech Health Ltd | Financial services | 2019 |
| Invedu Ltd | Real estate | 2017 |
| Invek Services Limited | Construction | 2011 |
| Invendium Ltd | Information & communication | 2002 |
| Invent Engineering Ltd | Professional & scientific | 2016 |
| Inventi Systems Ltd. | Information & communication | 2020 |
| Inventive Engineering Limited | Professional & scientific | 2023 |
| Inventory 2 Ltd | Information & communication | 2022 |
| Inventory My Property Limited | Other services | 2021 |
| Invergex Ltd | Professional & scientific | 2023 |
| INVERSION6 UK Limited | Information & communication | 2024 |
| Invesmart Limited | Real estate | 2023 |
| Invest Accountancy Ltd | Professional & scientific | 2011 |
| Invest in Treasure Ltd | Transport & logistics | 2026 |
| Invest Money Tree Group Ltd | Financial services | 2022 |