| Harworth Plant & Equipment Ltd | Leeds | 1991 |
| Harworth TRR Limited | Rotherham | 2014 |
| Hastech Limited | | 1998 |
| Hatfield Colliery Partnership Limited | Doncaster | 2013 |
| Hatford Quarry Limited | Marlborough | 1999 |
| Haud-Yer-Weesht Ltd | Laurencekirk | 2015 |
| Have-A-Go Limited | Dorking | 1998 |
| Havering Aggregates Limited | Canterbury | 1997 |
| Havila Group Limited | London | 2015 |
| Havila Trading Limited | London | 2015 |
| Hawcroft Consulting International UK Ltd | London | 2013 |
| Hawk Copper and Gold Ltd | London | 2025 |
| Hawk Reservoir Solutions Limited | King'S Lynn | 2005 |
| HAY Subsea Cable Solutions Ltd | Gosport | 2016 |
| Hayden Bishop Ltd | Lowestoft | 2024 |
| Hayne Quarry Ltd | Exeter | 2024 |
| Haysom Holdings Ltd | Poole | 2000 |
| Haysom Purbeck Stone Ltd | Poole | 1999 |
| Hayton of Fleetwood Limited | Manchester | 1983 |
| Haze Safety Solutions Ltd | Bolton | 2018 |
| Hbsuk Ltd | Manchester | 2016 |
| HCP1 Limited | Ayrshire | 2020 |
| HCS Aberdeen Limited | Glenrothes | 2018 |
| HD Exploration Limited | Woking | 2016 |
| Heads of the Valley Recycling Ltd | Swansea | 2021 |
| Health Industry Limited | Coventry | 2025 |
| Heard Upstream Consulting Ltd | Hemel Hempstead | 2017 |
| Heavy Duty Surplus Trading Limited | Louth | 2023 |
| Heavy Minerals Limited | London | 2019 |
| Heavy Minerals Research Consultants Limited | Ellon | 2017 |
| Hebridean Marine Services Ltd | Glasgow | 2023 |
| Hebridean New Metals Limited | Golspie | 2022 |
| Heightcorp Ltd | Lincoln | 2025 |
| Heightsector Limited | Inverness | 2015 |
| Helen Caroline Wright Limited | Exeter | 2024 |
| Helio-Flare Limited | Dundee | 2013 |
| Helios 9 Energy Ltd | London | 2026 |
| Helios Eastwest Ltd | London | 2025 |
| Helios Helium Ventures UK Limited | Marlow | 2011 |
| Helios OIL and GAS UK Limited | London | 2025 |
| Helium One (UK) Limited | Richmond | 2017 |
| Helix Energy Solutions (U.K.) Limited | Aberdeen | 2005 |
| Helix Exploration PLC | London | 2023 |
| Helix Offshore Services Limited | Aberdeen | 2019 |
| Helix OIL & GAS (U.K.) Limited | Aberdeen | 2018 |
| Helm Engineering Ltd | Peterhead | 2019 |
| Henan Yirui Chem Co., Ltd. | Beckenham | 2024 |
| Henderson Stratigraphic Ltd | Egremont | 2024 |
| Hendre Stone Ltd | Ystrad Meurig | 2019 |
| Henlys Heritage Limited | Northwich | 2023 |
| Hennichemaali Geosciences Limited | Woking | 2017 |
| Henry Dickinson Limited | Inverness | 2024 |
| Henry Streeter (Sand & Ballast) Limited | Oxted | 1955 |
| Hensall Quarry Limited | Lutterworth | 2021 |
| Heptagone Ltd | London | 2024 |
| Herbert Mitchell Limited | Newport | 2012 |
| Hereford Quarries Ltd | Hereford | 2014 |
| Herefordshire Sandstone Supplies Ltd | Hereford | 2006 |
| Heriot-Watt Trading Limited | Edinburgh | 1991 |
| Heritage OIL (UK) Limited | London | 2010 |
| Heritage Quarry Group (North) Limited | Chipping Norton | 2022 |
| Heritage Quarry Group (South) Limited | Chipping Norton | 2020 |
| Heropower Limited | London | 1992 |
| Herrano Investments Ltd | London | 2025 |
| Herrnhut UK Ltd | London | 2016 |
| Hertz Geosolutions Ltd | Milton Keynes | 2016 |
| Hess (Indonesia-South Sesulu) Limited | London | 2007 |
| Hess Limited | London | 1964 |
| Hess Malaysia and Thailand Limited | London | 2012 |
| Hewitt Robins International Holdings Limited | Swadlincote | 2007 |
| Hexa Resources Limited | London | 2016 |
| Hexis Training Limited | Great Yarmouth | 2020 |
| Hexton-Myers Limited | Birmingham | 2013 |
| HG Wells Ltd | Norwich | 1997 |
| Hgec Capital Limited | Glasgow | 2018 |
| HGH Resources Limited | Princes Risborough | 2015 |
| HGM Solutions Limited | Middlesbrough | 2019 |
| HHE Lifting Ltd | Middlesbrough | 2025 |
| HHH Consultants Limited | Leeds | 2023 |
| Hi-Access (Scotland) Limited | Dundee | 2001 |
| Hi-Impact Energy Limited | Westhill | 2015 |
| Hi-Tech Coaches Limited | North Benfleet | 2015 |
| Hibernian Energy Projects Ltd | Brechin | 2019 |
| High Latitude Risk Advisory Ltd | Kilmacolm | 2026 |
| High Peak Access Ltd | Buxton | 2022 |
| High Power Petroleum (Caribbean) UK Limited | London | 2018 |
| High Speed Building Materials Trading Ltd | Ruislip, | 2025 |
| High View Aerial and Rope Access Solutions Ltd. | Southport | 2011 |
| Highcountry UK Limited | South Nutfield | 2010 |
| Highfield Estates Lancashire Ltd | Chorley | 2021 |
| Highfield Global Resources Ltd | Montrose | 2011 |
| Highland Geology Limited | Newcastle Upon Tyne | 1995 |
| Highland Petroleum Limited | London | 2014 |
| Highland Resource Group Ltd | Glasgow | 2026 |
| Highland Rigging & Lifting Ltd | Alness | 2025 |
| Hillhouse Estates Limited | Ayrshire | 1945 |
| Hillhouse Quarry Group Limited | Ayrshire | 1991 |
| Hills Quarry Products Limited | Swindon | 2001 |
| Hillsborough Resources Limited | London | 2025 |
| Hilltop Aggregates Ltd | Omagh | 2011 |