| Mehfar Limited | Administrative & support | 2026 |
| Mehraj Retail Ltd | Wholesale & retail | 2025 |
| Mehran Medics Limited | Health & social care | 2011 |
| Mehta Services Ltd | Administrative & support | 2023 |
| Meily Spa Ltd | Other services | 2018 |
| Meister-Construct Limited | Construction | 2024 |
| MEK Housing Ltd | Real estate | 2025 |
| Melaad Limited | Other services | 2017 |
| Melanin Mums C.I.C. | Professional & scientific | 2026 |
| Meletius Ltd | Wholesale & retail | 2020 |
| Mellow Stays Ltd | Hospitality | 2025 |
| Melo Coffee Ltd | Hospitality | 2026 |
| Melody Consulting Services Ltd | Professional & scientific | 2026 |
| Melonias Assemblage Ltd | Health & social care | 2023 |
| Melromin Global Network Ltd. | Transport & logistics | 2023 |
| Melting Cube Ltd | Hospitality | 2023 |
| Meltz Treats Limited | Manufacturing | 2008 |
| MEM Cafe Limited | Hospitality | 2012 |
| Memo Plastering Ltd | Construction | 2024 |
| Memories Tech Ltd | Information & communication | 2024 |
| Mengfu Ltd | Hospitality | 2024 |
| Menoassess Holdings Ltd | Professional & scientific | 2023 |
| Menoassess Limited | Professional & scientific | 2023 |
| Menras Limited | Professional & scientific | 2022 |
| Meow Town Ltd | Wholesale & retail | 2020 |
| Mercantile Credit and Finance Ltd | Administrative & support | 2019 |
| Mercantile Financial Consultants Limited | Professional & scientific | 1999 |
| Merchant Trade Corporation Ltd | Professional & scientific | 2024 |
| Meridian Pharma Limited | Extraterritorial | 2009 |
| Merimba A1 Investments UK Limited | Professional & scientific | 2018 |
| Merraky Engineering Solutions Limited | Administrative & support | 2020 |
| Merrycan Ltd | Wholesale & retail | 2026 |
| Mersey Shipping Limited | Transport & logistics | 2025 |
| Meshiera Trading Ltd. | Wholesale & retail | 2025 |
| Messenger Magazine CIC | Information & communication | 2023 |
| Meta POS Ltd | Information & communication | 2023 |
| Metacube Wellness Ltd | Health & social care | 2019 |
| Metal Terminal Ltd | Wholesale & retail | 2026 |
| Metalex Ltd. | Professional & scientific | 2009 |
| Metamate Ltd | Hospitality | 2026 |
| Metos Design & Build Limited | Construction | 2018 |
| Metro Health & Beauty Limited | Wholesale & retail | 2007 |
| Metro Kitchens & Bedrooms Limited | Construction | 2015 |
| Metro Telworks Services Limited | Information & communication | 2015 |
| Mettle Properties Ltd | Real estate | 2020 |
| Mettle Properties MGT Ltd | Financial services | 2022 |
| MF Wolf Holdings Limited | Professional & scientific | 2015 |
| Mfcoil Limited | Construction | 2014 |
| MFE Asset Limited | Real estate | 2017 |
| Mfsl Ltd | Professional & scientific | 2024 |
| MG Accident Solutions Ltd | Financial services | 2026 |
| MG Global Medical Consultancy Ltd | Health & social care | 2012 |
| MG IT Consulting Limited | Information & communication | 2020 |
| MG Town Traders Ltd | Wholesale & retail | 2025 |
| Mgg-My Green Gardens Limited | Professional & scientific | 2024 |
| Mgineering Ltd | Manufacturing | 2026 |
| MGP London Ltd | Construction | 2013 |
| Mgsc Builders Ltd | Construction | 2023 |
| MH Distributions Ltd | Wholesale & retail | 2015 |
| MH Infrastructure and Environmental Limited | Construction | 2013 |
| MH Italian Gelato Ltd | Hospitality | 2025 |
| MH Media & Technology Ltd | Information & communication | 2024 |
| MH Payroll Services Limited | Professional & scientific | 2025 |
| MH Technologies Limited | Manufacturing | 2024 |
| MHA Nexus Ltd | Construction | 2025 |
| MHC LDN Limited | Wholesale & retail | 2023 |
| MHJ Builders Ltd | Construction | 2024 |
| MHM Productions Limited | Information & communication | 2023 |
| MI Amor Hub Ltd | Other services | 2020 |
| MI Compliance Solutions Limited | Professional & scientific | 2019 |
| MIA Global London Limited | Wholesale & retail | 2025 |
| MIA Khyle Ltd | Real estate | 2024 |
| Miafilm Limited | Professional & scientific | 2013 |
| Miao's Studio Limited | Arts & recreation | 2025 |
| Miban Ltd | Construction | 2025 |
| Michael a Martins Ltd | Information & communication | 2018 |
| Michael K Properties Ltd | Real estate | 2023 |
| Michaela Community Schools Trust | Education | 2011 |
| Microtech Technology Ltd | Information & communication | 2007 |
| Middlesex Broadcasting Corporation Limited | Information & communication | 1996 |
| Middlesex Homes Limited | Real estate | 2020 |
| Middlesex Meat Company Holdings Limited | Professional & scientific | 2018 |
| Middlesex Refurb Limited | Construction | 2010 |
| Midfood UK Ltd | Hospitality | 2017 |
| Midnight Customs Ltd | Wholesale & retail | 2026 |
| Mifima Ltd | Professional & scientific | 2008 |
| Mighty Y Ltd | Information & communication | 2011 |
| Mijiz Ltd | Real estate | 2024 |
| Mikaliza Autos Ltd | Wholesale & retail | 2025 |
| Mikas-Nikas Ltd | Real estate | 2023 |
| Mike Mccormack Electrical Services Ltd | Construction | 2016 |
| Mikuniya UK Ltd | Hospitality | 2025 |
| Mila Active Ltd | Wholesale & retail | 2025 |
| Mila P Ltd | Wholesale & retail | 2024 |
| Milan Group Limited | Construction | 2023 |
| Milanish Limited | Real estate | 2024 |
| Milano Hall Limited | Real estate | 2020 |
| Mile Ltd | Real estate | 2004 |
| Miles Consultants Ltd | Information & communication | 2019 |
| Milfoam International Limited | Wholesale & retail | 2000 |