| Harold F.Ward Limited | Birmingham | 1932 |
| Harold House Flat Management Company Limited | Hockliffe | 2004 |
| Harold Mitchell & Company Limited | Belfast | 1948 |
| Harold Mitchell (Banbridge) Limited | Belfast | 1965 |
| Harold Mitchell (Dromore) Limited | Belfast | 1994 |
| Harold Moore & SON Limited | Bradford | 2008 |
| Harold Moore Products Limited | Sheffield | 1996 |
| Harold Radford (Coachbuilders) Limited | Midlands West | 2004 |
| Harolds Tyres Limited | Winchester | 2002 |
| Haroldshaw Enterprise Limited | Southampton | 2024 |
| Harosey Ltd | Kington | 2024 |
| Harp Overseas Holdings Limited | Pontypridd | 1996 |
| Harpcombe Limited | Newmarket | 1975 |
| Harpenden Blinds Limited | Harpenden | 2009 |
| Harpenden Ltd | Harpenden | 2010 |
| Harper & Eede,Limited | Essex | 1933 |
| Harper Green Consultancy Ltd | Kilmarnock | 2021 |
| Harper Investment Group Ltd | Birmingham | 2022 |
| Harper Living Limited | Nottingham | 2020 |
| Harper Marketing Ltd | Saffron Walden | 2024 |
| Harper Property Developments Limited | Tipton | 2017 |
| Harper Truck and Plant Limited | Harrogate | 2013 |
| Harperdan Consulting Limited | Chelmsford | 2018 |
| Harperfield Limited | Ayrshire | 1999 |
| Harperley Estates Ltd | Stanley | 2013 |
| Harpers of Hertfordshire Ltd | London | 2024 |
| Harpers of Norfolk Ltd | London | 2024 |
| Harpers of Suffolk Ltd | London | 2024 |
| Harpers Plus Limited | London | 2022 |
| Harpin's Funeral Service Limited | Nottingham | 1919 |
| Harpington Limited | Stockton-On-Tees | 2021 |
| Harpolean Incorporated Ltd | Northampton | 2021 |
| Harprule Limited | Matlock | 1976 |
| Harpworth Limited | Salford | 2002 |
| HARR1S Limited | Harrogate | 2016 |
| Harrells Fertilizer Ltd | Gillingham | 2019 |
| Harriba International Ltd | London | 2023 |
| Harries Cardiac Imaging Ltd | Chard | 2022 |
| Harriet Rose Terri ANN Owen Limited Limited | Bridgend | 2024 |
| Harriman Homes Limited | York | 1996 |
| Harrington 1963 Limited | Grantham | 2014 |
| Harrington Family Law Ltd | Cleckheaton | 2015 |
| Harrington Horses Limited | Melksham | 2010 |
| Harris & Rowe (Commercials) Limited | Newport | 1985 |
| Harris & Trotter Consultants Ltd. | London | 2005 |
| Harris Allday Limited | London | 1987 |
| Harris Bidco Limited | Ormskirk | 2024 |
| Harris Business Development Ltd | Newcastle | 2021 |
| Harris Container Services Limited | Thaxted, Dunmow | 2026 |
| Harris Containers Limited | Dunmow | 2026 |
| Harris Distribution Limited | Northampton | 1962 |
| Harris Gardens 1966 Limited | Sittingbourne | 2014 |
| Harris Home Developments Limited | London | 2024 |
| Harris Home Holdings Limited | London | 2024 |
| Harris Home Investments Limited | London | 2024 |
| Harris Interior Solutions Limited | Fareham | 2016 |
| Harris Management Services Limited | St Albans | 2008 |
| Harris Properties Scotland Limited | Dundee | 2023 |
| Harris Topco Limited | Ormskirk | 2024 |
| Harris Transport Limited | Chelmsford | 2025 |
| Harris Transport Services Limited | Thaxted | 2026 |
| Harris Tweed Flowers Limited | Perth | 2017 |
| Harris Westbrook Limited | Harrogate | 2025 |
| Harris Woods Ltd | Filey | 2021 |
| Harris-Walton Export Limited | West Midlands | 1977 |
| Harrisdesign Norway Limited | London | 2023 |
| Harrison & Co Development Ltd | Liverpool | 2017 |
| Harrison Bailey Group Limited | Cardiff | 2026 |
| Harrison Childcare Limited | Crewe | 2013 |
| Harrison Collier Limited | Prescot | 2009 |
| Harrison External Display Systems Limited | Newton Aycliffe | 2001 |
| Harrison Flagpoles Limited | Newton Aycliffe | 1999 |
| Harrison Galaxy Limited | Erdington, Birmingham | 2003 |
| Harrison Goodness Foundation | St. Leonards-On-Sea | 2011 |
| Harrison Ground Earthing Limited | Bishop Auckland | 2013 |
| Harrison Group Limited | Lincolnshire | 2006 |
| Harrison Holdings Ltd | Lincoln | 2015 |
| Harrison James Construction Ltd | West Malling | 2024 |
| Harrison Joyce Holdings Limited | Birmingham | 2012 |
| Harrison Mechanical Contracting Ltd | Newcastle Upon Tyne | 2025 |
| Harrison Portfolio & Projects Limited | Newbury | 2021 |
| Harrison Security Holdings 1 Limited | London | 2002 |
| Harrison Security Holdings Ltd | Lincoln | 2020 |
| Harrison Security Ltd | Lincoln | 2005 |
| Harrison's Beautique Limited | Middlewich | 2013 |
| Harrison's Signs & Graphics Limited | Sheffield | 2023 |
| Harrisons Group Limited | Lincoln | 2003 |
| Harrisons Security Holdings Limited | Lincolnshire | 2007 |
| Harrisons Security Ltd | Lincoln | 2004 |
| Harrisons Taxis Limited | Middlesbrough | 2012 |
| Harrisons Taxis of Whitby Limited | Middlesbrough | 2012 |
| Harriss Property (W) Limited | Lincoln | 2010 |
| Harro Construction Limited | East Grinstead | 2024 |
| Harrogate Analytics Limited | Woking | 2025 |
| Harrogate Commercial Limited | Harrogate | 2026 |
| Harrogate Finance Limited | Harrogate | 2026 |
| Harrogate Horseless Carriages Limited | Leeds | 2005 |
| Harrogate Printing Limited | Harrogate | 2015 |
| Harrogate Residential Developments Limited | Harrogate | 2026 |
| Harrogate Scaffolding Limited | Harrogate | 1994 |