| Higgins City Limited | Construction | 1993 |
| Higgins Group PLC | Professional & scientific | 1989 |
| Higgins Group Services Limited | Construction | 1978 |
| Higgins Homes (Chobham Farm) Limited | Construction | 1978 |
| Higgins Homes PLC | Construction | 1965 |
| Higgins Investments PLC | Real estate | 1989 |
| Higgins Partnerships 1961 PLC | Construction | 1961 |
| High Impact Events Limited | Arts & recreation | 2000 |
| High Road 182 Limited | Real estate | 2017 |
| High Sky Limited | Wholesale & retail | 2025 |
| High Star Production Company Limited | Arts & recreation | 2005 |
| High Stile Projects Limited | Arts & recreation | 2009 |
| High Voltage Project Solutions Ltd | Professional & scientific | 2022 |
| High-Tech Membrane Roofing Ltd | Construction | 2000 |
| Higharch Digital Limited | Administrative & support | 2018 |
| Highclere Investments Limited | Administrative & support | 1988 |
| Higherground Property Investments Ltd | Real estate | 2025 |
| Highfield Place Properties Limited | Real estate | 1961 |
| Highflyers Finance Ltd | Information & communication | 2024 |
| Highgate Tech Investment Ltd | Financial services | 2024 |
| Highlyrecommendedmindset Ltd | Information & communication | 2025 |
| Highsun Travels and Tours Ltd | Administrative & support | 2025 |
| Hilbery Chaplin Limited | Professional & scientific | 2000 |
| Hilbery Chaplin Residential Limited | Real estate | 1991 |
| Hilbery Chaplin Surveyors Limited | Real estate | 1991 |
| Hilcrest Design Limited | Manufacturing | 1976 |
| Hildale Stage School Limited | Education | 1999 |
| Hill (Nexus) Stevenage Limited | Households | 2024 |
| Hill Park Veterinary Group Limited | Professional & scientific | 2005 |
| Hill Wooldridge Accountants Limited | Professional & scientific | 2005 |
| Hill's Building Contractors (Streatham) Limited | Wholesale & retail | 1977 |
| Hillborne Limited | Transport & logistics | 2005 |
| Hillcrest Medical Services Ltd | Real estate | 2010 |
| Hilliard Homes Limited | Wholesale & retail | 2001 |
| Hills of Heybridge Limited | Financial services | 2007 |
| Hillside Flats Limited | Professional & scientific | 2007 |
| Hilmworks Consultancy Limited | Professional & scientific | 2023 |
| Hindu Cultural Society of Havering | Other services | 2005 |
| Hinxton Relocation Limited | Construction | 2007 |
| Hipart Ambe Ltd | Wholesale & retail | 2023 |
| Hirab Ltd | Wholesale & retail | 2023 |
| Hirani Homes Ltd | Real estate | 2022 |
| Histon Hardware Ltd. | Transport & logistics | 2006 |
| Hive Connection Ltd | Professional & scientific | 2025 |
| Hiwatt Limited | | 1986 |
| HKA Enterprise Limited | Other services | 2003 |
| HKT International Ltd | Real estate | 2022 |
| HLS 2000 Limited | Transport & logistics | 2000 |
| HM Property Renovations Ltd | Construction | 2025 |
| HM Residentials Ltd | Real estate | 2025 |
| HND Traders Ltd | Wholesale & retail | 2023 |
| HO HO LMD Limited | Hospitality | 2025 |
| Hoadh Limited | Wholesale & retail | 2024 |
| Hockley Enterprises (Essex) Limited | Manufacturing | 1973 |
| Hockley Plumbing and Heating Supplies Limited | Wholesale & retail | 2003 |
| Hoemarsh Electrical Contractors (Leeds) Limited | | 1978 |
| Hogan Rentals Ltd | Real estate | 2025 |
| Holgate's Properties Limited | Real estate | 1956 |
| Holiday Cottage Cleaning Services Limited | Administrative & support | 2021 |
| Holiday Solutions Limited | Administrative & support | 2003 |
| Holland on Sea Motors Limited | Wholesale & retail | 2006 |
| Hollinmere Ltd | Wholesale & retail | 2025 |
| Holloway BED & Breakfast Limited | Hospitality | 2000 |
| Hollys Housemaids Ltd | Administrative & support | 2025 |
| Holmes Group Management Services Limited | Professional & scientific | 2021 |
| Holroyd Components Limited | Manufacturing | 1972 |
| Holtdow Plumbing & Heating Services Limited | Construction | 2000 |
| Holyoak Estates Ltd | Real estate | 2002 |
| Home & Around U Ltd | Construction | 2019 |
| Home Made Bakery (Essex) Limited | Manufacturing | 1971 |
| Home Safety Certificate Ltd | Administrative & support | 2019 |
| Homebook Overseas Limited | Professional & scientific | 1989 |
| Homecastle House RTM Co. Ltd | Households | 2025 |
| Homecourt House RTM Company Limited | Households | 2024 |
| Homelea Limited | | 1995 |
| Homelet Services Ltd | Construction | 2021 |
| Homelyloft Limited | Wholesale & retail | 2025 |
| Homewidget Ltd | Wholesale & retail | 2025 |
| Hone Project Management Ltd | Professional & scientific | 2006 |
| Honeydam Health Limited | Health & social care | 2024 |
| Honourable Foods Limited | Manufacturing | 2024 |
| Hooleo Ltd. | Professional & scientific | 2015 |
| Hope Carehome Limited | Health & social care | 2022 |
| Hope Hands Limited | Health & social care | 2023 |
| Hopecrate Ltd | Wholesale & retail | 2026 |
| Hopscotch Day Nursery (Essex) Limited | Education | 2002 |
| Hoque and Haque Limited | Administrative & support | 2023 |
| Horace Community Homes Ltd | Wholesale & retail | 2025 |
| Horizon Estate Agents Limited | Real estate | 2004 |
| Hornchurch Academy Trust | Education | 2017 |
| Hornchurch Specsavers Limited | Wholesale & retail | 2002 |
| Hornett Bros & Co,Limited | Manufacturing | 1953 |
| Hornett Holdings Limited | Financial services | 1999 |
| Horngulf Limited | | 1979 |
| Horseshoe Property Limited | Real estate | 2012 |
| Hosekarn Motors Limited | | 1978 |
| Hosier Farms Limited | Professional & scientific | 2006 |
| Hostem Limited | Wholesale & retail | 2006 |
| Hotel Reading Ltd | Hospitality | 2025 |
| Houghton Mechanical Services Limited | Construction | 2024 |