| Handy to Know Ltd | Households | 2024 |
| Handyman Online Limited | Construction | 2004 |
| HANGER19 Ltd | Administrative & support | 2013 |
| Hanggies Limited | Wholesale & retail | 2023 |
| Hanover House (South Woodford) Management Company Limited | Households | 2014 |
| Hansard Owens Bridging and Commercial Ltd | Financial services | 2026 |
| Hanwell View Management Company Limited | Households | 2016 |
| Happy Boating Ltd | Manufacturing | 2022 |
| Happy Gilmore Golf Ltd | Construction | 2022 |
| Happy Go Store Limited | Wholesale & retail | 2022 |
| Haps-Haps Limited | Professional & scientific | 2005 |
| Haque Tech Ltd | Construction | 2025 |
| Haracon Limited | Information & communication | 2018 |
| Haraka Physio Ltd | Health & social care | 2025 |
| Harbour Views Management Company (Southleigh) Limited | Real estate | 2023 |
| Harbour Village (Ebbsfleet) Management Company Limited | Households | 2023 |
| Hard HAT Developers Limited | Construction | 2020 |
| Harden Legacy Investments Ltd | Real estate | 2022 |
| Hardings (Fletcher Way) Limited | Wholesale & retail | 2018 |
| Hardkins (2009) Limited | Construction | 2009 |
| Hardwick Court (Holmewood) Limited | Households | 2004 |
| Hardy Building Solutions Limited | Construction | 2015 |
| Hardy Energy Limited | Wholesale & retail | 2023 |
| Hargate Healthcare Ltd | Administrative & support | 2022 |
| Hargo Records Ltd | Information & communication | 2020 |
| Hargreaves Nortey Property Holdings Ltd | Real estate | 2021 |
| Harima UK Ltd. | Manufacturing | 2022 |
| Haris Travel Services Ltd | Transport & logistics | 2025 |
| Harkal Group Ltd | Construction | 2021 |
| Harlea Contracts Ltd | Construction | 2025 |
| Harman International Industries Limited | Wholesale & retail | 1980 |
| Harmony Digital Limited | Information & communication | 2023 |
| Harmony House Property Company Limited | Real estate | 2023 |
| Harnham Park Management Company Limited | Households | 2021 |
| Harpenden Block Paving Company Limited | Construction | 1999 |
| Harper Mill Management Company (NO2) Limited | Households | 2006 |
| Harpers Hounds Ltd | Wholesale & retail | 2025 |
| Harribelle Real Estate Limited | Real estate | 2021 |
| Harribrryce Automotive Ltd | Wholesale & retail | 2026 |
| Harrison, Mayer and Mayer Limited | Professional & scientific | 2020 |
| Harrogate Capital Limited | Real estate | 2006 |
| Harry Winks Promotions Ltd | Arts & recreation | 2015 |
| Hart Excavations Limited | Water & waste | 2008 |
| Hart Optimisation Services Limited | Professional & scientific | 2024 |
| Hartford Green Residents Management Company BUL Limited | Households | 2022 |
| Harthall Limited | Real estate | 2021 |
| Harts Fire Solutions Ltd | Professional & scientific | 2025 |
| Harty Enterprises Ltd | Hospitality | 2025 |
| Harty Properties Ltd | Real estate | 2026 |
| Harvard Place (Earls Colne) Management Company Limited | Households | 2020 |
| Harvest Hill (Maidenhead) Management Company Limited | Households | 2025 |
| Harvester Close (Royston) Management Company Limited | Households | 2018 |
| Harvey Mellish Services Ltd | Construction | 2014 |
| Harvey Rail T & C Services Ltd | Construction | 2025 |
| Harvey ROE Holdings Limited | Financial services | 2025 |
| Harvey ROE Limited | Real estate | 2015 |
| HAS E Digital Governance Ltd | Information & communication | 2023 |
| Hassan's Coffee Bar Limited | Wholesale & retail | 2014 |
| HAT Full of Data Ltd | Information & communication | 2024 |
| HAT Trick Consulting Ltd | Administrative & support | 2019 |
| Hatch a Home Ltd | Real estate | 2025 |
| Hathaway Fitness Ltd | Arts & recreation | 2018 |
| Hathaway Management Consultants Ltd | Manufacturing | 2011 |
| Hatiz Kitchen Ltd | Hospitality | 2025 |
| Hattam Brickwork Ltd | Construction | 2021 |
| Hatty Blue Recruitment Limited | Administrative & support | 2008 |
| HAU Cars Auto Ltd | Wholesale & retail | 2025 |
| Haus of HR Limited | Administrative & support | 2021 |
| Hauser Recruiting Ltd | Administrative & support | 2024 |
| Havergal Place Management Company Limited | Households | 2005 |
| Haverstock Grove Residents Association Limited | Households | 1962 |
| Haverstock Hill Residents Association Limited | Hospitality | 1996 |
| Havlot Ltd | Transport & logistics | 2017 |
| Hawes Close Residents Association Limited | Households | 1980 |
| Hawk Developments Herts Ltd | Real estate | 2015 |
| Hawk Incentives Holdings Limited | Administrative & support | 1983 |
| Hawk Incentives Trust Company Limited | Extraterritorial | 1996 |
| Hawkersgroundsmaintenance Ltd | Arts & recreation | 2025 |
| Hawkeye Ltd | Information & communication | 2024 |
| Hawkstone Developments Ltd | Construction | 2022 |
| Hawkswood Management Limited | Households | 2017 |
| Hawthorn Gardens Ltd | Administrative & support | 2016 |
| Hawthorne Rise Management Company Limited | Households | 2019 |
| Hawthorne Tax Consultancy Ltd | Professional & scientific | 2019 |
| Hayabusa Property Services Ltd | Real estate | 2017 |
| Haycrest Development Limited | Construction | 2025 |
| Haycrest SUB Limited | Construction | 2026 |
| Hazard Evaluation Laboratory (Consultants) Ltd | Professional & scientific | 1995 |
| HBB Exteriors Ltd | Administrative & support | 2024 |
| HBP Services Limited | Real estate | 2003 |
| HBS Care Ltd | Health & social care | 2011 |
| HCH Commerce Limited | Wholesale & retail | 2024 |
| HCH Green Limited | Professional & scientific | 2022 |
| HCL55 Ltd | Households | 2025 |
| HCS Hydraulics Limited | Manufacturing | 2018 |
| HCS Trading Limited | Wholesale & retail | 2012 |
| Hctg Limited | Arts & recreation | 2007 |
| HD Solutions Ltd | Construction | 2023 |
| HD Solutions Property Ltd | Households | 2026 |
| HDW Electrical Limited | Construction | 2022 |