| ML Fire Consultancy Ltd | Walton-On-Thames | 2020 |
| Mlama Ltd | Stockbridge | 2019 |
| MLE Services Ltd | Ulverston | 2003 |
| Mmac Holdings Ltd | Guildford | 2025 |
| Mmakanjera Limited | Sheffield | 2014 |
| Mmamc Solutions Limited | Sidcup | 2017 |
| Mmarss Ltd | Newcastle | 2025 |
| Mmcleansky Consultants Ltd | Mitcham | 2022 |
| MME Care Limited | Chesterfield | 2021 |
| Mmfdi Ltd | Loughton | 2025 |
| Mmhar Ltd | Warlingham | 2024 |
| MN Rahman Limited | Solihull | 2018 |
| MNW Solutions Limited | Reading | 2022 |
| MNY Healthcare Ltd | Birmingham | 2023 |
| MO Baroudi Limited | Penrith | 2025 |
| Mobile Clinical Services Ltd | London | 2024 |
| MOC Healthcare Ltd | Leicester | 2020 |
| Mocca Education Ltd | Sheffield | 2023 |
| Modern Chinese Medicine Health Center Ltd | London | 2024 |
| Modus Consultancy Ltd | Ashford | 2018 |
| Modus Healthcare Ltd | Peterborough | 2020 |
| MOE Occupational Therapy Services Ltd | London | 2025 |
| MOF Consulting Ltd | Goole | 2018 |
| Mofae Consulting Limited | London | 2022 |
| Mognolia Consulting Services Ltd | Stansted | 2025 |
| Mohamed Hussein Consulting Limited | London | 2008 |
| Mohila Ongon Association Ltd | London | 2025 |
| Mojo Well-Being and Resilience Specialist Ltd | Warwick | 2020 |
| Mokhei Limited | Rainham | 2023 |
| Moksha Fire System Limited | Pinner | 2026 |
| Moliztoks Health and Educational Services Ltd | Hornchurch | 2021 |
| Mom's Love S Limited | Slough | 2022 |
| Momentum Sports Therapy Ltd | Birmingham | 2025 |
| MON Fire Management Ltd | Holyhead | 2012 |
| Mon-Choisy Homes Ltd | Rainham | 2025 |
| Monahan Solutions Limited | Loughton | 2023 |
| Money Save Marketing Ltd | Cardiff | 2019 |
| Monihas Limited | Bristol | 2026 |
| Monix Fire Safety Ltd | Haverfordwest | 2024 |
| Monsterbash CIC | Bristol | 2025 |
| Montgomery Medical Ltd | Tugby | 2020 |
| Montresor Lock Ltd | London | 2016 |
| Montz Social Care Consultancy Limited | Luton | 2020 |
| Moonlight Career Guidance Ltd | Middlesbrough | 2026 |
| Moose Hall Worle Limited | Bristol | 2026 |
| Mopao&Son Ltd | Manchester | 2020 |
| Mopothecary Ltd | Basildon | 2024 |
| Morad Educational Services Limited | Leicester | 2024 |
| Moray Safety Solutions Ltd | Lossiemouth | 2026 |
| More Than a Thought Ltd | Worthing | 2025 |
| More Than Words Consulting Ltd | Horley | 2023 |
| Morest Limited | Birmingham | 2022 |
| Moreton Prison Services Limited | London | 1997 |
| Morgan and Nephew Health Care Limited | Northampton | 2021 |
| Morgan Fire Protection Limited | London | 1986 |
| Morgan Holistic Limited | Smethwick | 2023 |
| Morgan Talking Ltd | Brighton | 2018 |
| Moriel Healthcare Ltd | Cirencester | 2023 |
| Morleyland Limited | Horsham | 2016 |
| Moroccan British Competencies Network CIC | London | 2021 |
| Morphfit Gentle Movement Project Ltd | Hamilton | 2020 |
| Mors Health Limited | Milton Keynes | 2018 |
| Mosaic Heart CIC | Coventry | 2026 |
| Mosaicminds CIC | London | 2025 |
| Mose Health Care Ltd | Stirling | 2025 |
| Mosgeb Group Limited | Barnsley | 2022 |
| Motcombe Community Pool CIC | Eastbourne | 2022 |
| Mother Theresa Private Limited | Altrincham | 2022 |
| Mother's Touch Care Limited | Barking | 2023 |
| Mothers of Living C.I.C. | Cheltenham | 2023 |
| Mother’S of Pearl Group Ltd | Chichester | 2022 |
| Motion Safe Limited | Liverpool | 2021 |
| MOTIV8 Services Ltd | Birmingham | 2025 |
| Motol Care Limited | Rochester | 2019 |
| Motophoto Limited | London | 2012 |
| Mount Aureol Healthcare Professionals Limited | Stanford-Le-Hope | 2024 |
| Movecritic Limited | Hertford | 2024 |
| Movement Therapies Ltd | Oldham | 2023 |
| Moxie Concierge Ltd | London | 2020 |
| Moylagh Health Care Consultancy Ltd | Omagh | 2025 |
| MP Admin Services Ltd | Bournemouth | 2025 |
| MP4MSERVICES Ltd | Plymouth | 2022 |
| Mpherembe Limited | Birmingham | 2024 |
| Mpjg Consultancy Ltd | Southport | 2021 |
| MPR Fire Solutions Ltd | Huddersfield | 2019 |
| Mpss Ltd | Canterbury | 2026 |
| Mpume’S Limited Limited | Colchester | 2026 |
| Mqhiki Chiliza Limited | St. Helens | 2022 |
| MR P J Revington Ltd | Bristol | 2021 |
| MR Risk Ltd | Maidstone | 2024 |
| MR Safety Services Ltd | Stoke-On-Trent | 2024 |
| MR T MAK & SI Ltd | Keighley | 2025 |
| Mr.Plus Ltd | Edgware | 2024 |
| MRB Fire Safety Services Ltd | Gloucester | 2023 |
| MRC Security Services Limited | Manchester | 2026 |
| Mreb Consultancy Limited | Crewe | 2013 |
| MRG Health Ltd | Brigg | 2022 |
| MRS Gonsalves Gynaecology Private Care Limited | Cardiff | 2016 |
| MRS Jones School of Excellence Ltd | Tendring | 2022 |
| Mrsafety Limited | Scunthorpe | 2026 |