| Hilltown Quarry Limited | Londonderry | 2022 |
| Himalayas Natural Gems Miners Limited | Tunbridge Wells | 2016 |
| Hirola Energy Ltd | London | 2020 |
| Hisem Ltd | London | 2022 |
| Historic Horsham Stone Limited | Broadbridge Heath | 2011 |
| HJ Devine Services Ltd | Wallsend | 2024 |
| HJ GEO Limited | Monmouth | 2024 |
| HJI Ltd. | Newbiggin-By-The-Sea | 2013 |
| HJR Oils Ltd | Aylesbury | 2018 |
| HKS Tech Limited | Surrey | 2003 |
| HL Corrosion Services Ltd | Stonehaven | 2023 |
| HLF Technical Services Limited | Guisborough | 2016 |
| HLI Services Ltd | Inverness | 2024 |
| HLL Inspection Limited | Stockton-On-Tees | 2018 |
| HMS Jent Ltd | City Of London | 2006 |
| HNG Geological Ltd | Aberdeen | 2013 |
| Hnglobal Limited | London | 2001 |
| HNM Invercauld Limited | Golspie | 2025 |
| HOB UK Energy and Mining Investments Ltd | London | 2025 |
| Hoboil Limited | Banchory | 2011 |
| Hochschild Mining Holdings Limited | London | 2006 |
| Hochschild Mining PLC | London | 2006 |
| Hoddam Contracting Company Limited | Lockerbie | 1958 |
| Hogan Aggregates Ltd | Caernarfon Road | 1964 |
| Hogan Energy Bank GRP Co Limited | London | 2009 |
| HOH Oilfield Services Limited | Wendover | 1998 |
| Hoist-Uk Ltd | Edinburgh | 2017 |
| Holcim UK Cement Limited | Coalville | 2014 |
| Holcim UK Limited | Coalville | 1930 |
| Holford GAS Storage Limited | Edinburgh | 2003 |
| Holgate Excavations Limited | Keighley | 1990 |
| Holland Amit International Co., Ltd | Cambridge | 2026 |
| Holland Aster Crop Nutrition Co., Ltd | Cambridge | 2024 |
| Holland Aston Agricultural Group Co., Ltd | London | 2025 |
| Holland Borun Plant Protection Co., Ltd | Cambridge | 2026 |
| Holland Bridgeson Chemical Co., Ltd | Hatfield | 2025 |
| Holland Energy Solutions Limited | Dorchester | 2010 |
| Holland Hexing Special Fertilizer Co., Ltd | Cardiff | 2026 |
| Holland Huaniu Group (UK) Co., Ltd | Beckenham | 2024 |
| Holland Meschley International Group Limited | Cambridge | 2026 |
| Holland Nuoerkang International Chemical Group Co., Ltd | Manchester | 2023 |
| Holland Sievte Chemical Group Ltd | Cambridge | 2021 |
| Hollfeld Limited | Aberdeen | 2001 |
| Hollingworth Inspection Services Limited | Elland | 2018 |
| Hollow Park Sand and Gravel Limited | Magherafelt | 2016 |
| Hollybank Environmental Limited | Brierley Hill | 2025 |
| Hollybank Quarry Limited | Brierley Hill | 2019 |
| Hollybush Minerals Ltd | Whitby | 2012 |
| Holm Geological Consultancy Limited | Dunoon | 2007 |
| Holy Ghost Mines Limited | Barrow-In-Furness | 2024 |
| Holy Ghost Mining Limited | Barrow-In-Furness | 2025 |
| Holywell Minerals Limited | London | 1961 |
| Holywell Resources Limited | Fareham | 1995 |
| Holywell Rigging Ltd | Plymouth | 2018 |
| Honister Slate Mine Limited | Keswick | 2002 |
| Hood Energy Limited | Aberdeen | 2022 |
| Hope Solutions & Technitions Ltd | North Shields | 2019 |
| Hoque Group Limited | Aberdeen | 2015 |
| Horeb Mining Ltd | London | 2022 |
| Horizon Energy Group Ltd | Aberdeen | 2025 |
| Horizon Geology Ltd | Stratford-Upon-Avon | 2023 |
| Horizon Industrial Services Ltd | Glasgow | 2017 |
| Horizonte Exploration Limited | London | 2005 |
| Horizonte Minerals PLC | London | 2006 |
| Hornet Geoconsulting Ltd. | King'S Lynn | 2005 |
| Horse Hill Developments Ltd | London | 2013 |
| Horsham Stone and Reclamation Ltd | Stockton-On-Tees | 2011 |
| Hose International Limited | Edinburgh | 2017 |
| Hourglass Africa Limited | London | 2022 |
| Howell Rigging Limited | Aberdeen | 2023 |
| Howford Recycling Limited | Corbridge | 2011 |
| Howie Minerals Limited | Aberdeen | 2001 |
| Howk Limited | Peterhead | 1996 |
| HPI (Ireland) Limited | Belfast | 2004 |
| HPT Property Holdings Limited | Braintree | 2025 |
| HQ Estates Limited | Great Yarmouth | 2019 |
| Hqme Limited | Coleraine | 2014 |
| Hrafn Projects (International) Limited | Aberdeen | 2021 |
| HRC Safety Limited | Glasgow | 2011 |
| HRH Geological Services International Limited | Aberdeen | 2009 |
| HRH Limited | | 1989 |
| HSE-4U2 Limited | London | 2021 |
| Hse-Pro Ltd | London | 2024 |
| HSF Petroleum Services Limited | Sheffield | 2011 |
| HTD Wilkins Limited | Bath | 2020 |
| HTX Products Ltd | Retford | 2022 |
| HTX Solutions Limited | Sherborne | 2019 |
| Hughes Technical Management Ltd | Wirral | 2013 |
| Hughes Tool Company Ltd | Clayton Le Moors | 2019 |
| Humber Commissioning Ltd | Blackpool | 2020 |
| Humber Gathering System Limited | London | 2017 |
| Humber Inspection (International) Limited | Immingham | 1996 |
| Humber Sand and Gravel Limited | Coventry | 1993 |
| Humbly Grove Energy Limited | Alton | 2003 |
| Humboldt Minerals Ltd | London | 2020 |
| Hummingbird Resources Limited | London | 2005 |
| Hunter Group (Scotland) Limited | Kilmarnock | 2009 |
| Hunter Mining (Offshore) Limited | Kilmarnock | 2012 |
| Huriya Gold Ltd | London | 2020 |
| Hurst, Moore & Peters Limited | London | 2015 |