| HSR Consulting Limited | Professional & scientific | 2011 |
| Hualing Property Limited | Real estate | 2023 |
| Hualing UK Limited | Financial services | 2023 |
| Humberside International Airport Limited | Transport & logistics | 1987 |
| Hunter and Company Property Limited | Real estate | 2015 |
| Hunter Wallace Ltd | Professional & scientific | 2019 |
| Hunters Gate Management Company Limited | Households | 2003 |
| Huntley Electrical Limited | Construction | 2014 |
| Huntley Rawlins Limited | Administrative & support | 2023 |
| Hutchings Pharmaceuticals Ltd | Wholesale & retail | 2025 |
| HW Planning Ltd | Professional & scientific | 2008 |
| Hyatt Corp Ltd | Information & communication | 2016 |
| Hybrid Herbs Limited | Hospitality | 2014 |
| Hyperbaric Health and Healing Limited | Health & social care | 2020 |
| Hyperscout Ltd | Information & communication | 2020 |
| Hypso Media Ltd | Information & communication | 2025 |
| HYR Talent Ltd | Administrative & support | 2026 |
| I & C Heating & Plumbing Limited | Construction | 2016 |
| I DID IT My K Limited | Arts & recreation | 2014 |
| I Love Street Food Ltd | Hospitality | 2023 |
| I&D Foods (East Sussex) Ltd | Hospitality | 2024 |
| I.C.M. Alarms Ltd | Construction | 2007 |
| Ibex Consulting Engineers Limited | Construction | 2021 |
| Iceberg Ventures Ltd | Professional & scientific | 2019 |
| Iconic Display and Installation Ltd | Manufacturing | 2025 |
| Iconic Group Ltd | Manufacturing | 2015 |
| Iconic Studios London Ltd | Information & communication | 2026 |
| ICW Technologies Limited | Information & communication | 2023 |
| Idos Online Limited | Wholesale & retail | 2013 |
| Ifelight Limited | Administrative & support | 2023 |
| IG Bond Ltd | Other services | 2018 |
| Igait Finaconsult Ltd | Professional & scientific | 2014 |
| IGF Business Credit Limited | Financial services | 2016 |
| IGF Group Services Limited | Professional & scientific | 2016 |
| IGF Invoice Finance Limited | Financial services | 1988 |
| Ignis Safety Services Ltd | Professional & scientific | 2001 |
| Ignite Accounting Limited | Professional & scientific | 2021 |
| Ijac Consulting Ltd | Professional & scientific | 2018 |
| IK Consulting Engineers Limited | Professional & scientific | 2014 |
| IM Alesha Ltd | Wholesale & retail | 2020 |
| Imaginology Services Limited | Information & communication | 2012 |
| Imanfit Ltd | Wholesale & retail | 2023 |
| Immortalis Collectables Limited | Wholesale & retail | 2025 |
| Impact Design Solutions Limited | Professional & scientific | 2017 |
| Impigra Aviation Holdings Limited | Transport & logistics | 2019 |
| IN Front Automotive Ltd | Manufacturing | 2015 |
| IN Search of Africa Limited | Transport & logistics | 2010 |
| IN the Name of Love Community Interest Company | Health & social care | 2025 |
| IN2DRAMA Ltd | Extraterritorial | 2021 |
| IN2PERFORMANCE Limited | Education | 2021 |
| Included Laundry Ltd | Administrative & support | 2012 |
| Independent Growth Finance Limited | Professional & scientific | 2016 |
| Independent Lifestyle Options Holdings Limited | Professional & scientific | 2009 |
| Independent Lifestyle Options Ltd | Health & social care | 2005 |
| Independent Retailers Association - UK Limited | Administrative & support | 2026 |
| Indian Ruchita Restaurant Ltd | Hospitality | 2020 |
| Indian Singles Network Ltd | Administrative & support | 2026 |
| Indielane Ltd | Wholesale & retail | 2026 |
| Indigo Couriers Ltd | Transport & logistics | 2025 |
| Inesite Limited | Professional & scientific | 2017 |
| Infinite Destinations Limited | Administrative & support | 2023 |
| Infinity Business Group Limited | Real estate | 2018 |
| Infinity Exchange Limited | Extraterritorial | 2016 |
| Infinity Jewellery Limited | Wholesale & retail | 2006 |
| Infinity Prive Limited | Professional & scientific | 2016 |
| Infinova Nutra Ltd | Wholesale & retail | 2025 |
| Inflatable Funtime Ltd | Arts & recreation | 2022 |
| Ingredients Direct Europe Limited | Administrative & support | 2014 |
| Inhouse Innovation LLP | | 2020 |
| Inico Recruitment Limited | Professional & scientific | 2026 |
| Initiate Developments Ltd | Real estate | 2019 |
| INK Real Estate Ltd | Real estate | 2025 |
| Innotrax Ltd. | Professional & scientific | 2016 |
| Innovapro LLP | | 2025 |
| Inprint Digital Solutions Limited | Manufacturing | 2013 |
| Inqlusive Ltd | Information & communication | 2021 |
| INR Enterprises Limited | Education | 2014 |
| Insight Info Ltd | Professional & scientific | 2023 |
| Inspiral Flooring Ltd | Construction | 2016 |
| Inspired Landscapes and Groundwork Limited | Construction | 2019 |
| Inspirina Limited | Professional & scientific | 2009 |
| Insure Broker Group Limited | Financial services | 2024 |
| Integro Homes Ltd | Construction | 2020 |
| Inteliaris Ltd | Financial services | 2018 |
| Intelligent Tomorrow Ltd | Energy | 2022 |
| Inter Legends Football Club Limited | Arts & recreation | 2025 |
| Interface Controls Limited | Construction | 2022 |
| Intermeats Limited | Wholesale & retail | 2012 |
| Intermove Systems Limited | Transport & logistics | 2002 |
| International Babysitters Ltd | Administrative & support | 2018 |
| International Health and Activity Travel (Group) Ltd | Administrative & support | 2024 |
| Interviewme Ltd | Information & communication | 2023 |
| Invest Heating Ltd | Construction | 2025 |
| Investment Governance Services Limited | Professional & scientific | 2019 |
| Invicta Estates Limited | Real estate | 1964 |
| Invicta Water Treatment Limited | Water & waste | 2002 |
| Invicta Window Films Limited | Construction | 1995 |
| Ipadel Ltd | Arts & recreation | 2015 |
| Ipanema Property Ltd | Real estate | 2020 |
| Ipostra Ltd | Information & communication | 2025 |