| Hands in Harmony Home Care Services Limited | Health & social care | 2008 |
| Hands on Babies Limited | Health & social care | 2008 |
| Handskull Limited | Information & communication | 2011 |
| Handsome Sketch Developments Limited | Construction | 2017 |
| Handtmann Limited | Wholesale & retail | 1985 |
| Handy Cash Machines Limited | Administrative & support | 2009 |
| Handybear Ltd | Wholesale & retail | 2022 |
| Handyworx MK Ltd | Construction | 2023 |
| Haneen Fashion Ltd | Wholesale & retail | 2023 |
| Haniel Recruitment Services Ltd | Information & communication | 2018 |
| Hanimex Consulting Limited | Professional & scientific | 2019 |
| Hanjo Russell Limited | Extraterritorial | 2001 |
| Hanmire Bespoke Tailoring Limited | Manufacturing | 2019 |
| Hanna's Beauty Bar Limited | Other services | 2022 |
| Hannah at Nuda Ltd | Other services | 2024 |
| Hannah Edwards Permanent Cosmetics Ltd | Other services | 2015 |
| Hannah Whitmore PMU Ltd | Other services | 2023 |
| Hannah's Pets Ltd | Professional & scientific | 2018 |
| Hannat Rapid Response Ltd | Administrative & support | 2019 |
| Hannelie Fourie Limited | Health & social care | 2011 |
| Hanoi Lounge Ltd | Hospitality | 2025 |
| Hanover Three Limited | Extraterritorial | 1945 |
| Hanpower UK Limited | Wholesale & retail | 2022 |
| Hanrooh Limited | Wholesale & retail | 2024 |
| Hansh Solutions Limited | Information & communication | 2015 |
| Hanslope Tyres and Servicing Ltd | Wholesale & retail | 2024 |
| Hanu&Co Properties Ltd | Real estate | 2024 |
| Hanvi Ltd | Information & communication | 2021 |
| Hanx Limited | Manufacturing | 2015 |
| HAO JIE KJ Ltd. | Wholesale & retail | 2025 |
| HAO Tian Crossborder Ltd | Wholesale & retail | 2025 |
| Haon Homes Ltd | Construction | 2019 |
| Haon Ltd | Administrative & support | 2016 |
| Hapn Property Management Limited | Real estate | 2026 |
| Happi Consultancy Ltd | Information & communication | 2023 |
| Happicup Cafe Ltd | Hospitality | 2024 |
| Happy Balance Ltd | Health & social care | 2018 |
| Happy Bins Ltd | Administrative & support | 2023 |
| Happy Days MK Ltd | Professional & scientific | 2019 |
| Happy Home Healthcare Ltd | Health & social care | 2021 |
| Happy Odju Limited | Transport & logistics | 2018 |
| Happy Snappy Day Ltd | Wholesale & retail | 2024 |
| Happy Tails Haven UK Limited | Wholesale & retail | 2025 |
| Happycus Ltd | Wholesale & retail | 2020 |
| Hapsart Resource Services Limited | Transport & logistics | 2016 |
| Harana Services Ltd | Health & social care | 2025 |
| Harandy Ltd | Health & social care | 2022 |
| Harbans Investments Limited | Information & communication | 2025 |
| Harbor & Vale Commerce Ltd | Wholesale & retail | 2025 |
| Harbour Light Care Ltd | Health & social care | 2025 |
| Harbrook Land & Property Limited | Construction | 1998 |
| Harcourt Health Hub Ltd | Health & social care | 2012 |
| Hard BOP Films Ltd | Information & communication | 2021 |
| Hardcastle Blake (LB) Limited | Professional & scientific | 2010 |
| Hardcastle Media Ltd | Information & communication | 2022 |
| Hardcore Integrated Services Limited | Extraterritorial | 1997 |
| Hardcover Regenerated Ltd | Wholesale & retail | 2023 |
| Hardflip Limited | Information & communication | 2017 |
| Harding Homes (Building & Maintenance) Limited | Construction | 2024 |
| Harding Homes (Kent) Limited | Real estate | 2022 |
| Harding's Bespoke Flooring Limited | Construction | 2025 |
| Hardiv Ltd | Information & communication | 2020 |
| Hardiv TEJ Properties Ltd | Real estate | 2024 |
| Hardlife (UK) Ltd | Manufacturing | 2011 |
| Hardlife Production Limited | Manufacturing | 2018 |
| Hardlife Support Limited | Professional & scientific | 2019 |
| Hareem MK Limited | Hospitality | 2017 |
| Harice Rose Education & Event Services Limited | Professional & scientific | 2023 |
| Harini Group Ltd | Transport & logistics | 2026 |
| HARJAS1 Transport Ltd | Transport & logistics | 2025 |
| Harlequin Gymnastics Academy Limited | Real estate | 2025 |
| Harlequin Press Limited | Manufacturing | 2011 |
| Harlequin Project Developments Ltd | Construction | 2019 |
| Harlesden Gardens Ltd | Real estate | 2025 |
| Harley Street Dental Laboratory Limited | Health & social care | 2017 |
| Harlida Limited | Real estate | 2025 |
| Harlow IS Limited | Information & communication | 2016 |
| Harlowdata Limited | Information & communication | 2024 |
| Harlwoods Ltd | Other services | 2018 |
| Harman CAD Services Limited | Administrative & support | 2015 |
| Harmantech Limited | Construction | 2025 |
| Harmet Limited | Other services | 2023 |
| Harmon Davis Limited | Wholesale & retail | 2015 |
| HARMONI8 Holdings Limited | Financial services | 2025 |
| Harmonix Care Limited | Administrative & support | 2024 |
| Harmony Business Systems Limited | Information & communication | 2012 |
| Harmony Care Qualty Group Limited | Health & social care | 2018 |
| Harmony Network Technology Ltd | Wholesale & retail | 2025 |
| Harmonypsa Holding Limited | Professional & scientific | 2017 |
| Harmonywheel Ltd | Other services | 2024 |
| Harnish Properties Limited | Financial services | 2023 |
| Harnstrom Ltd | Wholesale & retail | 2022 |
| Harold Investment Limited | Financial services | 2014 |
| Harold Wood Property Management Ltd | Households | 2019 |
| Harpenden Auto Services Ltd | Wholesale & retail | 2003 |
| Harper Luxe Dunstable Limited | Construction | 2021 |
| Harper Luxe Limited | Real estate | 2011 |
| Harper Nielsen Limited | Information & communication | 2023 |
| Harpers Nursery School Limited | Health & social care | 2005 |
| Harpy Studio Design Ltd | Manufacturing | 2022 |