| Medomsley Organics Limited | Rowlands Gill | 2019 |
| Medshrum Ltd | London | 2024 |
| Medusa's Menagerie Ltd | Skelmersdale | 2025 |
| Medwell Hempson Farms Ltd T/A M H F Ltd | Market Harborough | 1959 |
| Medwyn Livestock Services Limited | Lanark | 2014 |
| Medwyns' of Anglesey Garden Products Limited | Bodorgan | 2009 |
| MEE Contracting Limited | Wellingborough | 2012 |
| MEE Growers Ltd | Peterborough | 2009 |
| Meeks Trading Ltd | Middlesbrough | 2019 |
| Meelie Ltd. | Whalsay | 2011 |
| Meen Agri Services Limited | Spalding | 2020 |
| Meephill House Stables Limited | Ledbury | 2019 |
| Meer Booth Game Farm Limited | | 1977 |
| Meercats Maine Coon Cattery Dorset Ltd | Poole | 2022 |
| Meerkat Retreat Surrey Limited | Betchworth | 2025 |
| Meese Farming Limited | Newport | 1997 |
| Mega Dogs NI Ltd | Armagh | 2022 |
| Mega Land Investments Limited | London | 2022 |
| Mega Pink Horse Ltd | Warrington | 2012 |
| Megamax Traders Limited | Thornton Heath | 2017 |
| Megan Ingham Dressage Ltd | Wokingham | 2024 |
| Megginson Plant Hire Limited | Driffield | 2018 |
| Mehigan Land Management Ltd | Orston | 2018 |
| Mehmet-Guest Equestrian Limited | London | 2023 |
| Mehr Abbas Pro Limited | Northern Lreland | 2025 |
| Meic Hughes CYF | Pwllheli | 2015 |
| Meifod ISA Ltd | Dyffryn Ardudwy | 2020 |
| Meikle Bros. Limited | Rugby | 1952 |
| Meikle Cloak Limited | Renfrewshire | 1993 |
| Meikle Farming Limited | Banbury | 2015 |
| Meikle Findowie Limited | | 2002 |
| Meiklebob Farming Company Limited | Carlisle | 2004 |
| Mein Farming Company Limited | Dumfries | 2012 |
| Meithrin Y MÔR CIC | Mold | 2026 |
| MEK Farm Limited | Omagh | 2014 |
| Meko UK Group Ltd | London | 2024 |
| Mektron Ltd | Dereham | 2025 |
| MEL Investments Ltd. | Buckie | 2007 |
| Mel's Mutz Dog Grooming Ltd | Leigh-On-Sea | 2017 |
| Mel-Able Farming Limited | Kings Lynn | 1966 |
| Melanie Farming Holdings Limited | Alton | 2005 |
| Melanie Jenkins Farming Limited | Alton | 2005 |
| Melanie S Fishing Limited | Maghera | 2009 |
| Melbourn Farms Limited | Duxford | 1990 |
| Meldon Seeds Ltd | Peebles | 2020 |
| Meldon Village Storage and Drying Limited | South Shields | 2000 |
| Melfort Farms Limited | Oban | 1982 |
| Meliora Farm CIC | Heathfield | 2026 |
| Meliora Kittens Ltd | Beverley | 2024 |
| Melius Innovations Limited | Norwich | 2024 |
| Mell Fell Regen Ltd | Penrith | 2023 |
| MELL123 Limited | Harrogate | 2015 |
| Mellor & Plowright Ltd | Nottingham | 2025 |
| Mellor Equine Limited | Stockport | 2012 |
| Mellor Tree Surgeons Limited | Southampton | 2011 |
| Mellor's Farmers & Butchers Limited | Horncastle | 2005 |
| Mellow Grove Ltd | Cullompton | 2013 |
| Mellow Meats Ltd | Brackley | 2020 |
| Mells Spirits Limited | London | 2024 |
| Melmerby Estates Limited | London | 2011 |
| Melpur Ltd | Bridgend | 2021 |
| Melrose Agronomy Ltd | Colchester | 2025 |
| Melrose Bros Ltd | Newtown | 2020 |
| Melrose Farm Limited | London | 2017 |
| Melrose Pigs Limited | York | 2011 |
| Melry (FR) Ltd | Fraserburgh | 2016 |
| Melsetter Farms Ltd | Stromness | 2020 |
| Melton Animal Centre Ltd | Enfield | 2023 |
| Melton Contracting Ltd | Wisbech | 2019 |
| Melton Mowbray Pork Company Ltd | Melton Mowbray | 2014 |
| Melton Soil Sampling Ltd | Wisbech | 2019 |
| MEM Fisheries Consultants & Services Limited | Leicester | 1995 |
| Membury Estates Ltd | Marlborough | 2023 |
| Memorial Forest Limited | Kington | 2019 |
| Mena Group International Limited | London | 2026 |
| Menace Limited | London | 2012 |
| Menai Mussels Limited | Porthmadog | 2015 |
| Menai Oysters and Mussels Limited | Llanfairpwll | 2012 |
| Menalhyl Farm Ltd | Newquay | 2025 |
| Mendelita Ltd | Brough | 2015 |
| Mendez Consulting Limited | Milton Keynes | 2013 |
| Mendhams Farm Ltd | Wisbech | 2022 |
| Mendip Farmers' Hunt Fallen Stock Limited | Wells | 2014 |
| Mendip Forestry Limited | Westbury | 1984 |
| Mendocino Ltd | Newton Abbot | 2015 |
| Menhinick Contract Services Ltd | Dunmow | 2022 |
| Menin Limited | Dungannon | 2012 |
| Mental Health Connections Ltd | Bridgend | 2013 |
| Menter Amaethwyr Llanfihangel A'R Cylch CYF | Conwy | 2005 |
| Mentha Nurseries Limited | Wisbech | 1991 |
| Mentmore Game Farm Limited | Winslow | 2017 |
| Mentmore Park Farms Limited | Leighton Buzzard | 1991 |
| Meon Marine Ltd | Fareham | 2021 |
| Meon Meadows Ltd | Hassocks | 2020 |
| Meon Springs Limited | Petersfield | 2012 |
| Meon Valley Honey Ltd | Southampton | 2023 |
| Meon Valley Services Limited | Chandler'S Ford | 2002 |
| Meopham Valley Vineyard Ltd | Gravesend | 2015 |
| Meow Meow Cafe Ltd | London | 2025 |
| Meow Meow Farm Ltd | Oxford | 2025 |