| Haer Holdings Ltd | Financial services | 2022 |
| Hair Inc Ltd | Other services | 2015 |
| Halazar Pharma Limited | Manufacturing | 2006 |
| Halberstram Limited | Professional & scientific | 2005 |
| Halcona Limited | | 2002 |
| Hale Lodge Harrow (Management) Limited | Real estate | 1981 |
| Halford Investment Limited | Administrative & support | 2002 |
| Hall & Sons(Dairy Farmers)Limited | Agriculture & fishing | 1937 |
| Halpenny Developments Limited | Construction | 1999 |
| Hamilton Associates (London) Limited | Manufacturing | 1989 |
| Hamilton Meadow Ltd | Real estate | 2024 |
| Hamilton Thorne Holdings UK Limited | Financial services | 2019 |
| Hamlet Culture (UK) Limited | Education | 1997 |
| Hammonds Consultants Ltd | Professional & scientific | 2002 |
| Hampstead Construction Limited | Construction | 2004 |
| Hampton Hill Property Services Ltd | Households | 1996 |
| Hampton Management Resources Ltd | Professional & scientific | 2001 |
| Hanlake Import Export Limited | Extraterritorial | 2001 |
| Hanlake Limited | Extraterritorial | 2001 |
| Hanns Limited | Wholesale & retail | 2003 |
| Hanson Insurance Services Limited | Financial services | 1998 |
| Hanumaan Limited | Health & social care | 2005 |
| Hanxin Limited | Professional & scientific | 2003 |
| Happy Rings Limited | Wholesale & retail | 2019 |
| Hardwood Floors Direct Limited | | 1999 |
| Harefield Housing Limited | Real estate | 2018 |
| Harish Finance Limited | Wholesale & retail | 1975 |
| Harkos Investments Ltd | Real estate | 2007 |
| Harleyford Court Management Company Limited | Households | 1966 |
| Harp London Ltd | Real estate | 2022 |
| Harpastum Publishing Limited | Arts & recreation | 2002 |
| Harren Services Limited | Transport & logistics | 1987 |
| Harringtons Builders PLC | Construction | 2001 |
| Harrison Fields Limited | Real estate | 2000 |
| Harrison Land & Property Ltd | Construction | 2015 |
| Harrow International Schools Limited | Other services | 2009 |
| Harrow School Enterprises Limited | Wholesale & retail | 1982 |
| Harrow School of Gymnastics | Arts & recreation | 1991 |
| Harrow Specsavers Limited | Wholesale & retail | 1994 |
| Harrow View Complex Management Company Limited | Households | 2006 |
| Harrow Visionplus Limited | Wholesale & retail | 1994 |
| Harry MOT Centre Limited | Wholesale & retail | 2026 |
| Harvestwood Limited | Real estate | 1998 |
| Harwil Education Ltd | Education | 1996 |
| Hasham and Company Limited | Professional & scientific | 2003 |
| Haslam & Whiteway Limited | Wholesale & retail | 1972 |
| Hatch (Enfield) Management Company Limited(The) | Households | 1987 |
| Hatchbaks (Kingston) Limited | | 1977 |
| Haven Solutions Limited | Wholesale & retail | 1994 |
| Haverfield Ltd | Information & communication | 2003 |
| Havill Consulting Limited | Information & communication | 2003 |
| Hawkeye Media Ltd | Information & communication | 2002 |
| Hawthorn and ASH Courts Management Limited | Households | 1993 |
| Haydn Hughes & Co Ltd | Professional & scientific | 1994 |
| Haye Management Ltd | Other services | 2011 |
| Hayling Island Builders Limited | Real estate | 1960 |
| Hazel Byron Consulting Limited | Professional & scientific | 1999 |
| HB Accountancy & Consultancy Services Limited | Professional & scientific | 2007 |
| Headway Development (London) Limited | Construction | 2000 |
| Health Care Express Limited | Real estate | 1995 |
| Hearns Coaches Limited | Transport & logistics | 2003 |
| Heatfix Limited | Construction | 2003 |
| Heathfield Investments Limited | | 1981 |
| Heathfield Residents Limited | Real estate | 1994 |
| Heathrow (AH) Limited | Professional & scientific | 2007 |
| Heathrow (DSH) Limited | Professional & scientific | 2007 |
| Heathrow Holdco Limited | Professional & scientific | 2007 |
| Heathrow Linen Express Ltd | Other services | 2021 |
| Heathrow Plant Hire Limited | | 1970 |
| Heathview Investments Limited | Real estate | 2002 |
| Heatworks (UK) Limited | Construction | 2004 |
| Hedstrand Consultants Limited | Information & communication | 2005 |
| Hegland Systems Limited | Information & communication | 1991 |
| Heiwa Productions Ltd | Arts & recreation | 2016 |
| Helen Doron Effective Learning Limited | Administrative & support | 2001 |
| Helmy Limited | Wholesale & retail | 2003 |
| Hemco Limited | Extraterritorial | 1973 |
| Henley Properties Ltd | Real estate | 2005 |
| Henlow Health Limited | Wholesale & retail | 2004 |
| Henrik Svensson Paint FX Limited | Information & communication | 2013 |
| Herga Ibsc Limited | Arts & recreation | 1984 |
| Heron Walk Residents Limited | Other services | 1984 |
| Hertz (U.K.) Limited | Administrative & support | 1958 |
| Hertz Claim Management Limited | Financial services | 1995 |
| Hertz Europe Limited | Other services | 1971 |
| Heston Property Developments Limited | Real estate | 2001 |
| Hexham Properties Ltd | Households | 2015 |
| HFS Traffic Management Limited | Information & communication | 2012 |
| Hicity Limited | Wholesale & retail | 2003 |
| Hidden Pearl Productions Limited | Arts & recreation | 2002 |
| Highbird Builders Limited | Construction | 1998 |
| Highgate Forge Limited | Real estate | 2025 |
| Highland Scotch House Ltd | Other services | 2004 |
| Highmore Limited | Administrative & support | 2004 |
| Highriver Properties Limited | Real estate | 2002 |
| Hightop Trading Limited | Real estate | 2006 |
| Highworth Properties Limited | Real estate | 2005 |
| Higolf Limited | Administrative & support | 1988 |
| Hildons Limited | Extraterritorial | 2007 |
| Hill Close (Stanmore) Management Company Limited | Households | 1959 |