| House of Adullam Limited | Health & social care | 2025 |
| HOW & Son's Estates Limited | Real estate | 2020 |
| Howard Bridge & Associates Limited | Administrative & support | 1984 |
| Howard Norton Limited | Administrative & support | 2003 |
| Howells & Harrison (Southend) Limited | Health & social care | 1959 |
| Howlett Property Management Limited | Financial services | 2003 |
| Howlite Education and Consulting Ltd | Professional & scientific | 2026 |
| Hoxline Limited | Professional & scientific | 1999 |
| Hoxton EYE Centre Limited | Health & social care | 2005 |
| Hpan Meds Limited | Health & social care | 2024 |
| HQF Rendering Ltd | Construction | 2024 |
| Hr&Od Solutions Limited | Administrative & support | 2016 |
| Hsgraceis Property Ltd | Real estate | 2025 |
| HT Fresh Herbs Ltd. | Wholesale & retail | 2005 |
| HT House Ltd | Wholesale & retail | 2025 |
| HT Software U Ltd | Information & communication | 2022 |
| HTA IT Ltd | Professional & scientific | 2016 |
| Hudson Secretarial Services Limited | Professional & scientific | 1998 |
| Huge Construction 4U Limited | Construction | 2019 |
| Hughes Builders (Essex) Limited | Construction | 2002 |
| Hughes Water Coolers Limited | Wholesale & retail | 2001 |
| Huilee Limited | Wholesale & retail | 2023 |
| Hullbridge Tandoori Limited | Hospitality | 2018 |
| Humankind Comms Ltd | Professional & scientific | 2021 |
| Huncho Company Limited | Professional & scientific | 2021 |
| Hundred House Secretaries Limited | Administrative & support | 2000 |
| Hunmike Worldwide Ltd | Real estate | 2016 |
| Hunnable Finance Limited | Professional & scientific | 1978 |
| Hunnable Holdings Limited | Professional & scientific | 1973 |
| Hunt Motorcycles Ltd | Wholesale & retail | 1997 |
| Hunter & Reeves Limited | Professional & scientific | 2002 |
| Hunters Meet Limited | Hospitality | 2003 |
| Huntingdon Dragon Limited | Hospitality | 2022 |
| Hunts Roofing and Building Ltd | Construction | 2025 |
| Hupfer (UK) Limited | Professional & scientific | 1997 |
| Hurf Digital Limited | Information & communication | 2025 |
| Hurst Court Flats Limited | Real estate | 1961 |
| Husco Services Ltd | Construction | 2025 |
| Huskfusion Limited | Wholesale & retail | 2025 |
| Husmo Refrigeration Ltd | Manufacturing | 2023 |
| Hussain Sheikh Ltd | Administrative & support | 2019 |
| Hydrospec Limited | Construction | 1988 |
| Hype and Euphoria Limited | Wholesale & retail | 2026 |
| Hypervac Limited | Other services | 1978 |
| Hythehopes Limited | Information & communication | 1996 |
| HZ Digital Influence Ltd | Wholesale & retail | 2024 |
| I & I Assets Ltd | Real estate | 2017 |
| I and J Building and Maintenance Ltd | Construction | 2026 |
| I Autoworks Ltd | Wholesale & retail | 2021 |
| I C Phillips & Sons Limited | Construction | 2007 |
| I G Carpentry Services Ltd | Construction | 2004 |
| I J Little Services Limited | Construction | 2006 |
| I Q Formations Limited | Administrative & support | 2002 |
| I-Sire Ltd | Wholesale & retail | 2025 |
| I-Sire Services Ltd | Administrative & support | 2025 |
| I. B. Building Limited | Construction | 2003 |
| I. P. Interior's Limited | Construction | 2006 |
| I.D.P. UK Limited | Wholesale & retail | 1993 |
| I.P.M. (Rayleigh) Limited | Real estate | 1992 |
| I.S.I. Legend Ltd | Information & communication | 2000 |
| Ianua Capital Ltd. | Households | 2025 |
| IAS Security Services Ltd | Administrative & support | 2023 |
| Iasquare Ltd | Wholesale & retail | 2025 |
| IBC Properties Limited | Real estate | 1996 |
| Ibiayo Movies Limited | Information & communication | 2007 |
| Ibkm Consulting Limited | Information & communication | 2016 |
| Ibrahim Dynasty Ltd | Administrative & support | 2023 |
| IBW Academy Ltd | Administrative & support | 2024 |
| IC Carpentry Ltd | Construction | 2014 |
| Ice Digital Limited | Other services | 2003 |
| Ice Logistics Ltd | Hospitality | 2021 |
| Icli Cafe Ltd | Hospitality | 2023 |
| Iconcentrate Limited | Information & communication | 2005 |
| ICT Plus Limited | Information & communication | 2000 |
| Ideal Locations - Matchouse Ltd | Real estate | 2025 |
| Ideal Recruitment Ltd | Administrative & support | 2016 |
| Ideaone Limited | Construction | 1999 |
| Idiaz by ZK Ltd | Wholesale & retail | 2025 |
| IDK Services Limited | Professional & scientific | 2002 |
| Ieuan P.Evans & Co. Limited | | 1988 |
| IF They Care Homes Ltd | Health & social care | 2024 |
| Ifamily Limited | Real estate | 2023 |
| IGE Essex Limited | Construction | 2006 |
| Igknighted Contact Limited | Professional & scientific | 2007 |
| Ignite Logistics Ltd | Construction | 2020 |
| IGX Gaming Ltd | Wholesale & retail | 2026 |
| IHM Engineering Limited | Construction | 2004 |
| Ihmlogistics Ltd | Transport & logistics | 2026 |
| Ihrc Rescue Mission Ltd | Extraterritorial | 2025 |
| Iigc Ltd | Administrative & support | 2025 |
| Iino UK Ltd. | Transport & logistics | 2004 |
| Ikecare Limited | Health & social care | 2025 |
| Ilford Builders Limited | Construction | 2018 |
| Ilford Goodmayes Hotel Ltd | Hospitality | 2018 |
| Ilford Lane Properties Ltd | Real estate | 2020 |
| Ilford Parquet Company Limited | Financial services | 1978 |
| Ilford Properties Ltd | Real estate | 1999 |
| ILM Education Services Ltd | Education | 2026 |
| ILM Solutions Ltd | Information & communication | 1997 |
| Ilsleys Holdings Ltd | Financial services | 2025 |