| Mead Estates Lettings and Managements Limited | Real estate | 2012 |
| Mead Estates Properties Managements Ltd | Real estate | 2025 |
| Mead Estates Property Management Ltd | Real estate | 2018 |
| Mead Estates Property Services Ltd | Real estate | 2020 |
| Meadow Gardens Management Company (Yapton) Limited | Real estate | 2021 |
| Meadow Gate (Farington) Management Company Ltd | Households | 2019 |
| Meadow Place Sudbury Limited | Households | 2003 |
| Meadow View Road Limited | Households | 2003 |
| Meadow View Watchfield Management Company Limited | Households | 2015 |
| Meadow Walk (Stratford) Management Company Limited | Households | 2003 |
| Meadows LEA Management Company Limited | Households | 2009 |
| Meadway One Limited | Construction | 2011 |
| Meaningful Messages Ltd | Manufacturing | 2018 |
| Meant to BE Design Ltd | Professional & scientific | 2021 |
| Mearsbeck RTM Company Limited | Households | 2022 |
| Meat Giant UK Limited | Wholesale & retail | 2023 |
| Meat Master Croydon Ltd | Wholesale & retail | 2024 |
| Meat N Greet Ltd | Wholesale & retail | 2024 |
| Mece UK Limited | Hospitality | 2019 |
| Mechanical Management Services Ltd | Professional & scientific | 2022 |
| Mechanical Services EOT Limited | Administrative & support | 2018 |
| Mechanical Services Limited | Administrative & support | 1985 |
| MECHELEC4U Ltd | Professional & scientific | 2026 |
| Mechtric Ltd | Construction | 2024 |
| Med-Elan Limited | Administrative & support | 2002 |
| Medallion Court Management Limited | Households | 1985 |
| Medcore GP Limited | Health & social care | 2026 |
| Medgas Services Ltd | Construction | 2017 |
| Medhinbeauty Ltd | Wholesale & retail | 2025 |
| Medi Options Limited | Wholesale & retail | 2012 |
| Media Forte Ltd | Professional & scientific | 2017 |
| Media Relations Management Limited | Professional & scientific | 2007 |
| Mediacy Limited | Professional & scientific | 2019 |
| Mediart Limited | Health & social care | 2025 |
| Medibank Limited | Health & social care | 2012 |
| Medic One Services LLP | | 2017 |
| Medical Insight Limited | Real estate | 2007 |
| Medical Publications (Ireland) Limited | Information & communication | 1979 |
| Medical Resource Group Ltd | Health & social care | 2018 |
| Medical Vision Ltd | Professional & scientific | 1997 |
| Medicalead Ltd | Health & social care | 2025 |
| Medicare Pharm Ltd | Wholesale & retail | 2010 |
| Medicdent Intl Ltd | Manufacturing | 2025 |
| Medico Living Limited | Real estate | 2024 |
| Medicolegal Doctors Ltd | Administrative & support | 2009 |
| Medihealth Locums (MHL) Limited | Administrative & support | 2020 |
| Medilegal Limited | Health & social care | 2009 |
| Medimpo Holdings Limited | Financial services | 2018 |
| Medimpo Limited | Wholesale & retail | 1983 |
| Medina Movers Ltd | Transport & logistics | 2024 |
| Medipharma UK Limited | Health & social care | 2005 |
| Mediplan Health Limited | Information & communication | 2026 |
| Mediterranean Convenience Store Ltd | Wholesale & retail | 2019 |
| Mediterranean Investements Ltd. | Construction | 2018 |
| Medius Appanage Limited | Real estate | 1998 |
| Medley Jewellery Limited | Wholesale & retail | 2013 |
| Medline Clinic Ltd | Health & social care | 2023 |
| Medsun Ltd | Wholesale & retail | 2025 |
| Medumba Ltd | Transport & logistics | 2023 |
| Medusa (UK) Limited | Administrative & support | 2000 |
| Medwiz Supplies Limited | Manufacturing | 2024 |
| Meer Property Services Limited | Real estate | 2017 |
| Meeras UK Ltd | Manufacturing | 2021 |
| Meetupvideo Ltd | Information & communication | 2015 |
| Mega Wholesale MCR Ltd | Wholesale & retail | 2021 |
| Megadeals Hub Ltd | Wholesale & retail | 2025 |
| Megamall Limited | Wholesale & retail | 2009 |
| Megamile (Stableyard) Limited | Households | 1988 |
| Megapro Building Services Ltd | Construction | 2016 |
| Megawave Energy Ltd | Other services | 2022 |
| Megawave Energy Solutions Ltd | Construction | 2022 |
| Mehak Hair & Beauty Salon Limited | Other services | 2019 |
| Mehran Siraj Ltd | Wholesale & retail | 2025 |
| MEI Properties Limited | Real estate | 2012 |
| Meinstein Ltd | Other services | 2026 |
| Mejo Ltd | Other services | 2023 |
| Mekiv Limited | Wholesale & retail | 2016 |
| Mekros Limited | Information & communication | 2015 |
| MEL & SAM Investment Limited | Real estate | 2021 |
| MEL Resources Ltd | Professional & scientific | 2021 |
| Melbourne Builders Limited | Construction | 2015 |
| Melbourne House (Bristol) Management Limited | Households | 2002 |
| Melbury Court RTM Company Limited | Households | 2006 |
| Mellow Management Limited | Arts & recreation | 2026 |
| Melody Rose Limited | Administrative & support | 2014 |
| Melon Music Limited | Arts & recreation | 2024 |
| Melt Room Group Ltd | Hospitality | 2016 |
| Melt Room Ltd | Hospitality | 2014 |
| Melton Mowbray (Kirby Lane) Management Company Limited | Households | 2022 |
| Melucci Italian Delicatessen Limited | Hospitality | 2010 |
| Melvin Court Residents Association Limited | Households | 1983 |
| Melvyn Clarke Limited | Wholesale & retail | 1962 |
| Memoirs Photobooth Ltd | Other services | 2017 |
| Memorial Close Management Company Limited | Households | 1970 |
| Memory Lane Bears Ltd | Manufacturing | 2025 |
| Menchies Ltd | Wholesale & retail | 2026 |
| Mengke Culture and Entertainment Co., Ltd | Wholesale & retail | 2025 |
| Meno GP Clinics Ltd | Health & social care | 2025 |
| Mensajero Ltd | Transport & logistics | 2025 |
| Mentese Mobile Chef Services Limited | Hospitality | 2025 |