| HTZ Trading Ltd | Wholesale & retail | 2025 |
| Hugesense Leisure Ltd | Real estate | 2011 |
| Hughes Legal Consultants Limited | Professional & scientific | 2017 |
| Hughes Surgical Ltd | Health & social care | 2020 |
| Human Dynamics LAB Ltd | Professional & scientific | 2021 |
| Human Side HR Consultancy Ltd | Administrative & support | 2026 |
| Humanicks Consulting Ltd | Professional & scientific | 2006 |
| Humble Hydrogen Ltd | Construction | 2018 |
| Humphreys Wood Management Company Limited | Households | 2016 |
| Humphriss & Ryde Lettings Limited | Real estate | 2008 |
| Hunter Saint Financial Services Ltd | Financial services | 2016 |
| Hunters Grove (Leigh) Management Limited | Households | 2001 |
| HUQ Obstetrics and Gynaecology Limited | Health & social care | 2026 |
| Hurst Technology Solutions Limited | Information & communication | 2016 |
| Hurstwood Farm Piano Studios Limited | Administrative & support | 2002 |
| Hurtlewood Ltd | Health & social care | 2022 |
| Hutson's Hounds Ltd | Wholesale & retail | 2025 |
| HWS Physiotherapy Limited | Other services | 2025 |
| Hybrid Imaging Limited | Health & social care | 2012 |
| Hydro Heating South Limited | Construction | 2021 |
| Hydrostar Dynamics Ltd | Information & communication | 2025 |
| Hyperion Computing Limited | Information & communication | 2010 |
| Hypnos Medical Ltd | Health & social care | 2020 |
| Hyseni Holdings Ltd | Construction | 2023 |
| I AM the Storm Ltd | Wholesale & retail | 2018 |
| I M L Group Limited | Information & communication | 1989 |
| I. Wallond Fencing Contractors Ltd | Construction | 2013 |
| I2I-CONTRACTORS Ltd | Construction | 2016 |
| I3D Robotics Ltd | Manufacturing | 2013 |
| IA Convey Consulting Limited | Professional & scientific | 2021 |
| IAN Barkaway Holdings Ltd | Financial services | 2018 |
| IAN Hughes Productions Limited | Information & communication | 2014 |
| IAN Lloyd Associates Limited | Information & communication | 2002 |
| IAN Pike Consulting Limited | Professional & scientific | 2018 |
| IAN Read Setting Ltd. | Manufacturing | 2013 |
| IB3 Limited | Professional & scientific | 1999 |
| IBG Engineering Ltd | Wholesale & retail | 2025 |
| IBR Consultancy Ltd | Professional & scientific | 2017 |
| Ibrow Threading Lounge Limited | Other services | 2019 |
| Ice Wharf (KX) Ltd | Real estate | 2022 |
| Iconik Interiors Limited | Professional & scientific | 2020 |
| Icor Resources Limited | Professional & scientific | 2023 |
| Idealrate Management Limited | Households | 1988 |
| Iden Group Motors Limited | Wholesale & retail | 2025 |
| Iden Marketing Ltd | Professional & scientific | 2020 |
| Identity Press Limited | Manufacturing | 2003 |
| Idesk Ltd | Construction | 2020 |
| Idle Tyke Ltd | Professional & scientific | 2014 |
| Idoneous Limited | Financial services | 2008 |
| IDR Solutions Limited | Information & communication | 1999 |
| Iec-Ex Inspection Limited | Administrative & support | 2013 |
| IEM Medical Services Limited | Health & social care | 2011 |
| Ieps (Kent) Ltd | Education | 2012 |
| Ieps Holdings Limited | Financial services | 2021 |
| Ieps Property Limited | Real estate | 2021 |
| IFF Life and Business Solutions Limited | Administrative & support | 2009 |
| IFG Network UK Limited | Financial services | 2010 |
| Ifgn UK Limited | Financial services | 2019 |
| Igaming Future Ltd | Information & communication | 2020 |
| Ijoinery Ltd | Information & communication | 2016 |
| Ikiden Ltd | Professional & scientific | 2024 |
| Ikonoclast Ltd | Professional & scientific | 2018 |
| Imaginarium Group Ltd | Professional & scientific | 2024 |
| Imestore E-Commerce Company Ltd. | Wholesale & retail | 2013 |
| Imetrics Limited | Information & communication | 2000 |
| Impact Gym Ltd | Arts & recreation | 2024 |
| Impactus Ltd | Other services | 2015 |
| Implantology & MC Ltd | Health & social care | 2017 |
| Impressions Property Limited | Real estate | 2002 |
| In-Box Distributions (UK) Limited | Wholesale & retail | 2019 |
| In-So Consultants UK Ltd | Administrative & support | 2025 |
| Incentum Ltd | Other services | 2016 |
| Indelible Group Ltd | Information & communication | 2025 |
| Independent Building Consultancy Ltd | Professional & scientific | 2018 |
| Independent Contractors (Tonbridge) Limited | Other services | 1996 |
| Independent Design House Group Limited | Construction | 2022 |
| Independent Design House Limited | Professional & scientific | 2011 |
| Independent Directorships Limited | Professional & scientific | 2012 |
| INDI18 Limited | Hospitality | 2021 |
| Indigo Cherry Ltd | Information & communication | 2019 |
| Indigo Inquiries Limited | Professional & scientific | 2023 |
| Indigo Security Ltd | Construction | 2024 |
| Indigozoo Ltd | Professional & scientific | 2011 |
| Indipendant Limited | Administrative & support | 2021 |
| Industrial Equipment Finance Limited | Financial services | 2018 |
| Industrial Equipment Finance Services Limited | Financial services | 2018 |
| Industrial Media Limited | Information & communication | 1978 |
| Infinite State Games Ltd | Information & communication | 2013 |
| Infinity FM Ltd | Administrative & support | 2017 |
| Information Assurance Strategies Ltd. | Information & communication | 1994 |
| Informing Choices Limited | Professional & scientific | 2007 |
| Infotree Technologies Limited | Administrative & support | 2017 |
| Ingage Editions Limited | Information & communication | 2021 |
| Ingenium Property Development Ltd | Construction | 2018 |
| Inka Architecture Limited | Professional & scientific | 2025 |
| Inline Assembly Limited | Information & communication | 2011 |
| Inn Vision Multimedia Limited | Arts & recreation | 2000 |
| Innovate Facades Limited | Construction | 2019 |
| Innovations Heating and Electrical Ltd | Construction | 2020 |
| Innovative Way Limited | Information & communication | 2022 |