| Harco Carpentry Ltd | Manufacturing | 2025 |
| Harco Plumbing and Heating Ltd | Construction | 2019 |
| Harcross Limited | Construction | 1962 |
| Hardesty Event Design Ltd | Hospitality | 2021 |
| Hardex Ltd | Information & communication | 2025 |
| Harding Lister Law Ltd | Information & communication | 2012 |
| Hardingham Farms Limited | Agriculture & fishing | 1964 |
| Hardley Windmill Trust Limited | Arts & recreation | 2007 |
| Hardware Solutions Limited | Wholesale & retail | 2014 |
| Hardwick House Property Management Ltd | Administrative & support | 2013 |
| Hardy Drive Management Company Limited | Households | 2017 |
| Hardy Road Management Limited | Households | 2024 |
| Hare and Hounds (Harlton) Community Owned PUB Community Interest Company | Hospitality | 2017 |
| Hareson Property Ltd | Real estate | 2012 |
| Harewood Property Management Limited | Households | 2021 |
| Harford Attachments Limited | Manufacturing | 2008 |
| Harford House Maintenance Ltd | Administrative & support | 2018 |
| Harford Manufacturing Limited | Manufacturing | 1992 |
| Harford Residents Ltd | Households | 2025 |
| Hargham Properties Limited | Professional & scientific | 1973 |
| Harico Homes Limited | Construction | 2018 |
| Harilux Limited | Wholesale & retail | 2025 |
| Harlam Mortgages Ltd | Financial services | 2022 |
| Harlequin Fancy Dress Limited | Wholesale & retail | 2006 |
| Harling Pest Control Limited | Administrative & support | 2023 |
| Harling Plumbing Ltd | Construction | 2019 |
| Harling Sports Physiotherapy & Strength Conditioning Ltd | Arts & recreation | 2022 |
| Harling Sportspark Limited | Arts & recreation | 2016 |
| Harling Spraying Services Limited | Agriculture & fishing | 2025 |
| Harling Taxis Ltd | Transport & logistics | 2014 |
| Harlow Stewart Limited | Administrative & support | 2024 |
| Harmer Farms Limited | Agriculture & fishing | 2009 |
| Harmes Kebab Limited | Hospitality | 2025 |
| Harmony Estate Agents Ltd | Real estate | 2025 |
| Harmony Hair and Beauty (Blofield) Ltd. | Other services | 2012 |
| Harmony Home Improvements Limited | Construction | 1985 |
| Harmony Life Wellness Ltd | Health & social care | 2025 |
| Harmony Medical Practice Limited | Professional & scientific | 2013 |
| Harnden Food Services Ltd | Hospitality | 2024 |
| Harnser Property Investments Ltd | Real estate | 2024 |
| Harold and Sons Limited | Real estate | 2014 |
| Harold Ipsoff Limited | Real estate | 2021 |
| Harold Lynn Limited | Administrative & support | 2020 |
| Harolds Park Wildland Limited | Agriculture & fishing | 2024 |
| Harp Venture Capital Limited | Professional & scientific | 2010 |
| Harper & Debbage Limited | Wholesale & retail | 2016 |
| Harper Developments Ltd | Construction | 2018 |
| Harper Lomax Limited | Information & communication | 2017 |
| Harrier Homes Norfolk Ltd | Construction | 2017 |
| Harrington Menswear London Limited | Wholesale & retail | 2026 |
| Harrington Photography Limited | Professional & scientific | 2002 |
| Harris & James Aldeburgh Limited | Manufacturing | 2018 |
| Harris & James Chocolate Limited | Manufacturing | 2018 |
| Harris & James Foods Limited | Manufacturing | 2009 |
| Harris & James Limited | Wholesale & retail | 2017 |
| Harris & James Norfolk Limited | Wholesale & retail | 2020 |
| Harris & James Restaurants Limited | Hospitality | 2012 |
| Harris Family Company Ltd | Financial services | 2025 |
| Harrison & Mcgrath Developments Ltd | Construction | 2015 |
| Harrison Cladding Design Ltd | Professional & scientific | 2026 |
| Harrison Estate (East Anglia) Limited | Households | 2017 |
| Harrison Geotechnical Holdings Limited | Professional & scientific | 2022 |
| Harrison Group Environmental Limited | Professional & scientific | 1977 |
| Harrison Hide Ltd | Information & communication | 2025 |
| Harrison Homes (EA) Limited | Construction | 2014 |
| Harrison Management Limited | Real estate | 1996 |
| Harrison Wayne Ltd | Construction | 2025 |
| Harrisons Pipeline Engineering Limited | Manufacturing | 2005 |
| Harrison’S Utilities Ltd | Construction | 2023 |
| Harrod Horticultural Limited | Professional & scientific | 2005 |
| Harrold Property Limited | Real estate | 2018 |
| Harrups Holdings Ltd | Financial services | 2020 |
| Harrups Home Renovations Limited | Real estate | 2020 |
| Harry Andrew Hargreaves Limited | Extraterritorial | 2025 |
| Harry Andrew Munro Limited | Extraterritorial | 2025 |
| Harry Ford Consulting Ltd | Professional & scientific | 2025 |
| Harry Security Ltd | Other services | 2019 |
| Harry Watson Court Limited | Households | 2008 |
| Harrys Soul Station at Home Ltd | Hospitality | 2026 |
| Harrys Soul Station Ltd | Hospitality | 2022 |
| Harry’S Hot Honey Limited | Wholesale & retail | 2024 |
| Harshi Foods Ltd | Wholesale & retail | 2019 |
| Hart & Kohl Ltd | Professional & scientific | 2023 |
| Hart Advisory Services Ltd | Information & communication | 2026 |
| Hart Associates Limited | Financial services | 2024 |
| Hart Farm Developments Limited | Construction | 2019 |
| Hart PBR Ltd | Hospitality | 2025 |
| Hart Property Lets Ltd | Real estate | 2023 |
| Hart Stores Ltd | Wholesale & retail | 2017 |
| Hartlepool Solar Electric Forecourt Ltd | Energy | 2021 |
| Hartlepool West Solar Farm Ltd | Energy | 2020 |
| Hartlynn Limited | Transport & logistics | 2022 |
| Harts Farm (North) Management Company Limited | Households | 2003 |
| Hartswood Health and Aesthetics Ltd. | Health & social care | 2018 |
| Hartsworth Limited | Manufacturing | 2015 |
| Hartsworth Property Limited | Real estate | 2021 |
| Hartwell Data Ltd | Information & communication | 2014 |
| Harvana Limited | Financial services | 2020 |
| Harvest Crossing Limited | Wholesale & retail | 2022 |
| Harvest Energy (Fuel Cards) Limited | Wholesale & retail | 2019 |