| Incaresupply Ltd | Health & social care | 2023 |
| Incito Consulting Ltd | Information & communication | 2008 |
| Increase Sales Solutions Ltd | Administrative & support | 2013 |
| Incubatus LLP | | 2018 |
| Indemnifi Advisory Limited | Financial services | 2024 |
| Independent Cafe Owners Network Ltd | Wholesale & retail | 2023 |
| Independent Lives (Disability) | Information & communication | 2013 |
| Independent Lives (Trading) Limited | Health & social care | 2005 |
| Independent Options Ltd | Financial services | 2002 |
| Independent RAG Ltd | Wholesale & retail | 2003 |
| Independent Worthing Ltd | Wholesale & retail | 2021 |
| Indie Marketing Solutions Limited | Professional & scientific | 2025 |
| Individual Interiors Ltd | Professional & scientific | 2020 |
| Indus Applications Limited | Information & communication | 2020 |
| Infinit Corp Ltd | Hospitality | 2024 |
| Infinite Electric Solution Ltd | Construction | 2022 |
| Infinity Business Growth Network Limited | Administrative & support | 2014 |
| Infinity Hospitality Limited | Other services | 2021 |
| Infinity Legacy Ltd | Financial services | 2026 |
| Info NOW Solutions Limited | Information & communication | 2024 |
| Info Wire Limited | Public administration | 2017 |
| Information Security Forum Limited | Administrative & support | 2003 |
| Information Software Solutions Limited | Information & communication | 2000 |
| Infosectek Ltd | Information & communication | 2021 |
| Ingleside Limited | Households | 1996 |
| Ingram Cooper Properties Limited | Real estate | 2026 |
| Ingson Limited | Professional & scientific | 2003 |
| Inhouse Consulting Ltd | Professional & scientific | 2018 |
| INK Haven Tattooing Limited | Other services | 2017 |
| Inn House Productions Ltd | Information & communication | 2023 |
| Inndispensable Ltd | Manufacturing | 2017 |
| Innes Clan Properties Limited | Real estate | 2025 |
| Innovation Ventures UK Ltd | Information & communication | 2021 |
| Innovative Software Testing Solutions Limited | Information & communication | 2007 |
| INNOVE24 Ltd | Health & social care | 2022 |
| Inside OUT Aesthetics Limited | Health & social care | 2021 |
| Inside Publications Ltd | Information & communication | 2023 |
| Inside Recruitment Ltd | Administrative & support | 2024 |
| Insight International Development Management Ltd | Construction | 2016 |
| Insight Media Productions LLP | | 2022 |
| Insight Universal Limited | Professional & scientific | 2006 |
| Insights Accounting Ltd | Professional & scientific | 2020 |
| Insolvency and Recovery Limited | Professional & scientific | 2012 |
| Insp Consulting Ltd | Real estate | 2017 |
| Inspirational Consulting Ltd | Energy | 2010 |
| Inspire (Your Home) Limited | Construction | 2007 |
| Inspire Business Performance Ltd | Professional & scientific | 2021 |
| INSPIRE4CHANGE Consulting Ltd | Information & communication | 2014 |
| Inspired Design Solutions Ltd | Manufacturing | 2019 |
| Inspired Games (London) Limited | Manufacturing | 2024 |
| Inspired Health & Beauty Products Limited | Manufacturing | 2014 |
| Inspired Health Limited | Administrative & support | 2013 |
| Instapay Ltd | Wholesale & retail | 2019 |
| Integer Energy Limited | Professional & scientific | 2008 |
| Integrity Mortgages Limited | Financial services | 2013 |
| Intelligent Lime Limited | Information & communication | 2009 |
| Intelligent Sensing Ltd | Information & communication | 2024 |
| Intellum UK Limited | Information & communication | 2014 |
| INTENT91 Godalming Ltd | Health & social care | 2025 |
| INTENT91 Holdings Ltd | Administrative & support | 2022 |
| INTENT91 Horsham Ltd | Health & social care | 2022 |
| INTENT91 Ltd | Health & social care | 2018 |
| INTENT91 Portslade Ltd | Health & social care | 2021 |
| INTENT91 Sevenoaks Ltd | Health & social care | 2025 |
| Interbeing Film Ltd | Information & communication | 2025 |
| Interface Union Trade Limited | Construction | 1998 |
| Interfinish (UK) Limited | Wholesale & retail | 2010 |
| International Coach Ltd | Professional & scientific | 2022 |
| International Mini Market 7 Ltd | Wholesale & retail | 2026 |
| International Residence Management Limited | Administrative & support | 2023 |
| Intersite Services Ltd | Administrative & support | 2019 |
| Intrend Vending Ltd | Wholesale & retail | 2025 |
| Intrepidus by Design Limited | Construction | 2026 |
| Intro 2 FX Ltd | Financial services | 2020 |
| Invader Security Solutions Ltd. | Administrative & support | 2013 |
| Invenio Solutions Ltd | Information & communication | 2013 |
| Inventech Limited | Information & communication | 1996 |
| Investment Solutions Wealth Management Limited | Financial services | 2010 |
| Investology Limited | Real estate | 2021 |
| Investsave Limited | Real estate | 1994 |
| Iona Beesly Associates Limited | Financial services | 2007 |
| IOS Services Ltd | Professional & scientific | 2020 |
| Iosaiph Ltd | Wholesale & retail | 2024 |
| Ipro Security Consultancy Limited | Administrative & support | 2015 |
| IPS Facilities Limited | Other services | 2004 |
| Ipsfm Ltd | Other services | 2019 |
| IPW Consulting Limited | Professional & scientific | 2020 |
| IQ IT Services Ltd | Information & communication | 2018 |
| Iqiniti Ltd | Real estate | 2017 |
| Iren's Design Studio Ltd | Wholesale & retail | 2020 |
| Iron Gate TMS Ltd | Administrative & support | 2019 |
| Isanam Limited | Construction | 2019 |
| ISF Holdings Limited | Administrative & support | 2024 |
| Iskele (Worthing) Ltd | Hospitality | 2019 |
| Island Express Transport Limited | Professional & scientific | 1999 |
| Island Maintenance Limited | Administrative & support | 2012 |
| Island Site Protective Ltd | Administrative & support | 2021 |
| ISO Retail Ltd | Administrative & support | 2024 |
| Isor CIC | Education | 2020 |
| Isthiab Limited | Transport & logistics | 2024 |