| Mink Farm Ltd | Woking | 2024 |
| Minninnooka Ltd | Wellingborough | 2015 |
| Minor Trees Limited | Nottingham | 2021 |
| Minshull Farms Limited | Kenilworth | 2021 |
| Minster Enterprises Limited | Oxon | 1987 |
| Mint (Eco) Ltd | Derby | 2021 |
| Mint and Mustard Produce Ltd | Woodbridge | 2016 |
| Mint and Swift Tree Surgeons Limited | Borehamwood | 2019 |
| Minterburn Gundogs Ltd | Pershore | 2009 |
| Minters Tree Care Ltd | Canterbury | 2021 |
| Minwear Farm Limited | Narberth | 2004 |
| MIR Builders Ltd | St Austell | 2021 |
| Mirabello Estate Ltd | Richmond | 2020 |
| Mirage II Limited | Bridlington | 2010 |
| Mires Beck Nursery | Brough | 1994 |
| Miresdale Dairy Holding Limited | Carlisle | 2020 |
| Miresdale Dairy Limited | Carlisle | 2009 |
| Mirkwood Ltd | Ilford | 2022 |
| Miro Forestry Developments Limited | London | 2014 |
| Mirror Farm Limited | Saffron Walden | 2018 |
| Mirror Pool Fisheries Limited | Bourne End | 2000 |
| Mirza Farm Limited | Rochdale | 2024 |
| Misbister Limited | Stromness | 2015 |
| Miscanthus Growers Limited | Lincoln | 2010 |
| Miscanthus Nursery Limited | Taunton | 2009 |
| Miss Cavalier Ltd | Kettering | 2026 |
| Miss J L Moran & MR J R Carr Ltd | North Yorkshire | 2024 |
| Missing Dog Support Team CIC | London | 2023 |
| Missinglink Farming CIC | Gateshead | 2023 |
| Mission Pest Control Ltd | Swindon | 2022 |
| Mission Road Developments Limited | London | 2003 |
| Mission Zero Ltd | London | 2019 |
| Misson Organic Dairying Limited | Newark | 2016 |
| Misson Springs Lamb Limited | Doncaster | 2018 |
| Mistress Sea Charters Limited | Kings Lynn | 2007 |
| Misty Blue Farm Limited | Spennymoor | 2021 |
| Misty Blue Fishing Limited | Wimborne | 2025 |
| Mitcham Viticultural Services Ltd | Wantage | 2019 |
| Mitcham ZOO Ltd | Mitcham | 2021 |
| Mitchell (Drumdreel) Limited | Fife | 1978 |
| Mitchell By-Products Limited | Bradford | 1982 |
| Mitchell Countryside Services Ltd | Baldock | 2026 |
| Mitchell Garden & Cafe Ltd | Newquay | 2023 |
| Mitchell's Hardware Ltd. | Keith | 2011 |
| Mitchell's of Millhill Ltd | Fraserburgh | 2025 |
| Mitchell,Fox & Company Limited | | 1935 |
| Mitchells Potatoes (Somerset) Ltd | Taunton | 2000 |
| Mitchelmore Shellfish Limited | Kingsbridge | 2018 |
| Mitchem Brothers Limited | Cullompton | 2003 |
| Mitro Camp Ltd | Aberdeen | 2023 |
| Mitton Agricultural Ltd | Clitheroe | 2017 |
| Mitty Sports Horse Sales Ltd | Hereford | 2023 |
| MIU Aquatics Limited | Belvedere | 2022 |
| Miza Services Ltd | Crewe | 2025 |
| Mizinoiu Fishing Limited | London | 2025 |
| Mizpah 111 Ltd | Scarborough | 2026 |
| Mizpah Fishing Company Limited | Aberdeen | 1999 |
| Mizu Pathways UK Ltd | London | 2026 |
| MJ & J Mclaren Farms Limited | Perthshire | 2003 |
| MJ & SJ Worsley Ltd | Warrington | 2021 |
| MJ Agri & Equine Ltd | Winkleigh | 2024 |
| MJ and RD Russell Limited | Bristol | 2013 |
| MJ Bees Limited | Chelmsford | 2021 |
| MJ Farms Ltd | Derry | 2006 |
| MJ Fell Ltd | Lancashire | 2007 |
| MJ Forestry Ltd | Nairn | 2021 |
| MJ Goodwin & AJ Brown Ltd | Hereford | 2025 |
| MJ Higgins Contracting Ltd | Enniskillen | 2003 |
| MJ Marine & Building Ltd | Scalloway | 2023 |
| MJ Pest Control Limited | Leicester | 2013 |
| MJ Tree Services London Limited | London | 2015 |
| MJB Farming Limited | Melton Mowbray | 2025 |
| MJB Fencing Limited | Uttoxeter | 2019 |
| Mjbt Incorporated Ltd | Chelmsford | 2019 |
| MJC Land and Farm Limited | Poole | 2026 |
| MJC Tree Services Limited | Southampton | 2001 |
| MJC Tree Surgeons Limited | Curdridge | 2003 |
| MJD Farming Limited | Richmond | 2009 |
| MJD Poultry Limited | Crediton | 2015 |
| MJF Farms Ltd | Burton Upon Trent | 2024 |
| MJH & Sons Limited | Bristol | 2004 |
| MJH Farming Solutions Limited | Sudbury | 2011 |
| MJK Agri CYF. | Betws-Y-Coed | 2021 |
| MJL Deer Management Ltd | Balerno | 2022 |
| MJL Equestrian Limited | Westerham | 2015 |
| MJM (Farmers) Limited | Forres | 2005 |
| MJP Marine Ltd | Whalsay | 2014 |
| MJR Fishing Limited | Peterhead | 2020 |
| MJR Treeworks Ltd | Worcester | 2026 |
| Mjrw Contracting Limited | Mansfield | 2020 |
| MJS Baits Ltd | Doncaster | 2014 |
| MJS Hoofcare Limited | Berwick Upon Tweed | 2022 |
| MJS Services ( NW) Ltd | Liverpool | 2021 |
| MJT Agriculture Ltd | Tweskbury | 2026 |
| MJW Bloodstock Ltd | Winchester | 2026 |
| MJW Plant Ltd | Evesham | 2021 |
| MJW Sustain Limited | Bury St. Edmunds | 2020 |
| MK Equine and Pet Sitting Services Ltd | Caerphilly | 2025 |
| MK Events Centre Limited | Devizes | 2019 |
| MK Livestock Ltd | Omagh | 2024 |