| Maintain UK Waste Ltd | Wallsend | 2021 |
| Mainwood Limited | Edgware | 1990 |
| Majek Touch Enterprises Limited | London | 2025 |
| Majestic Cleaning Solutions Ltd | London | 2025 |
| Majestic Corporation P.L.C. | Deeside | 2021 |
| Majestic Solutions Services Limited | Harpenden | 2025 |
| Majestic Water Limited | London | 2012 |
| Majico Ltd | Cambridge | 2019 |
| Majkur Ltd | Edgware | 2019 |
| Majlis Energy Development & Ventures Limited | Edgware | 2026 |
| Major Water Limited | Kent | 2024 |
| Majors Construction Limited | Newark | 2005 |
| MAK Movers Ltd | London | 2025 |
| MAK Recycling Ltd | Bromsgrove | 2016 |
| MAK3 Pack & Recycle Ltd | Coatbridge | 2024 |
| Make IT Clear London Drain Unblocker Ltd | London | 2025 |
| Make Things Happen Removals Ltd | Wolverhampton | 2023 |
| Makerfield Metal & Recycling Limited | Wigan | 2018 |
| Makro Organics UK Ltd | Christchurch | 2024 |
| Makwaste Ltd | London | 2020 |
| Malanda Properties Limited | Taynuilt | 2004 |
| Malary Limited | Twentypence Road, Cottenham | 2006 |
| Malbry Furniture (Sales) Limited | Albert Square | 1986 |
| Malcolm International Limited | Manchester | 2015 |
| Malcolm Morris Limited | Newcastle Upon Tyne | 2026 |
| Maldon Metals Limited | Ilford | 2009 |
| Malin Group Properties Limited | Glasgow | 2017 |
| Mallard Grange Environmental Services Ltd | Foggathorpe | 2020 |
| Mallard Industrial Limited | Dudley | 2016 |
| Mallets Pallets and Recycling Ltd | Birmingham | 2026 |
| Malory Group Ltd | Darlington | 2026 |
| Malt Scrap Metal Collection Ltd | Bournemouth | 2021 |
| Maltby Restoration Limited | Sheffield | 2017 |
| Maltby Skip Hire Ltd | Rotherham | 2021 |
| Maltin Pollution Control Systems (1967) Ltd | Somerset | 1987 |
| Malvern Recycling Ltd | Worcester | 2014 |
| Malvern Skip Hire Ltd | Worcester | 2014 |
| Malverumb Recycling Ltd | Oldbury | 2023 |
| Mammoth Waste Limited | Portsmouth | 2015 |
| MAN and Van Movers Limited | Eastleigh | 2025 |
| MAN and Van Rubbish Removal Ltd | Dagenham | 2024 |
| MAN With Tipper Ltd | Huntingdon | 2024 |
| Managed Waste Services Limited | Bolton | 2008 |
| Manby Bio-Cng Production (1) Limited | Hayling Island | 2022 |
| Manchester City Waste Ltd | Manchester | 2026 |
| Manchester Drain Repair Ltd | Manchester | 2024 |
| Manchester Neon Contractors Limited | 72 Gartside Street | 1960 |
| Manchester Paper Plastic Ltd | Manchester | 2014 |
| Manchester Recycled Aggregates Limited | Warrington | 1999 |
| Manchester Recycling Limited | Manchester | 2020 |
| Manchester Shredding Limited | Cheadle | 2011 |
| Manchester Waste Away Ltd | Manchester | 2025 |
| Manchester Waste Management Ltd | Cheadle | 2025 |
| Mancunian Waste Services Limited | Manchester | 2021 |
| Mandrake Services PVT Ltd | Stratford Upon Avon | 2024 |
| Mands Bedding Ltd | London | 1997 |
| Mankind Reuse Ltd | London | 2025 |
| Mannings Waste Management Ltd | London | 2026 |
| Mannix Maintenance Limited | Brentwood | 2014 |
| Manns Skip Hire Ltd | Loughton | 2023 |
| Manns Waste Management Limited | Dagenham | 2009 |
| Manor Auto Salvage & Recycling Limited | Bristol | 2013 |
| Manor Enterprises Limited | Harrow | 1981 |
| Manor FM Ltd | Manchester | 2018 |
| Manor From Heaven Ltd | Minehead | 2025 |
| Manor Lane (Langham) Management Company Limited | Oakham | 1998 |
| Manorhouse Upholstery Limited | Bolton | 1987 |
| Manpower Logistics Ltd | Lambton | 1997 |
| Mansfield Drains Ltd | Mansfield | 2023 |
| Mansfield Eco Waste Solutions Ltd | Mansfield | 2026 |
| Mansfield Skip Hire and Waste Management Limited | Nottingham | 2018 |
| Mantisonix Ltd | Guildford | 2024 |
| Mantix - Install Ltd | Cardiff | 2016 |
| Manup Key Limited | Robertstown | 2017 |
| MAP Drainage Solutions Ltd | Basildon | 2026 |
| MAP Scrap Metals Limited | Crewe | 2014 |
| Mapal Aeration Limited | London | 2019 |
| Mapal Green Energy UK Limited | London | 2013 |
| Maple (140) Limited | Caldicot | 2000 |
| Maple Biomass Ltd | Long Eaton | 2020 |
| Maple Drainage Limited | Pontefract | 2017 |
| Mapledene Maintenance Limited | Meridian Business Park | 2022 |
| Maplin Services Limited | Basildon | 2019 |
| MAR Clearance Services Ltd | Margate | 2021 |
| MAR Land Reclamation Limited | Solihull | 1999 |
| Marc Contracts Limited | Midlothian | 2007 |
| Marcel & SON Cleaning Drainage and Maintenance Ltd | Plumstead | 2021 |
| Marcio Removal Services Ltd | Romford | 2025 |
| Marcus Young Environmental Services Ltd | Milton Keynes | 2009 |
| Marek Skrocki ''Prestige'' Limited | London | 2023 |
| Margetts PIT Limited | London | 1990 |
| Mariana WM Limited | Leicester | 2016 |
| Mariem's Heart Community Interest Company | London | 2025 |
| Marin RC Limited | Slough | 2021 |
| Marine & Boat Recycling Ltd | Easingwold | 2021 |
| Marine BIO Services Ltd | Billingham | 2013 |
| Marine Clearance Tech Ltd | Spalding | 2025 |
| Marine Decommissioning Services Limited | Sale | 2021 |
| Marine GRP Recycling Ltd | London | 2020 |
| Marine Recycling Limited | Poole | 2019 |