| Milford Peak Limited | Real estate | 2020 |
| Milk Cars Limited | Education | 2017 |
| Mill Hill Brazilian JIU Jitsu CIC | Education | 2023 |
| Mill Hill International Limited | Education | 2022 |
| Millennium Clinic Limited | Health & social care | 2007 |
| Millennium Glass London Ltd | Manufacturing | 2019 |
| Millennium Professional Services (UK) Limited | Professional & scientific | 1997 |
| Million Skin Aesthetics & Wellness Ltd | Health & social care | 2026 |
| Mills Venture Properties Limited | Real estate | 2023 |
| Millwork Infinity Ltd | Manufacturing | 2025 |
| Milrish Limited | Real estate | 2015 |
| Milton for Schools Construction Ltd | Construction | 2020 |
| Minas Home Ltd | Real estate | 2023 |
| Mind in Balance Limited | Health & social care | 2013 |
| Mind Path Media Ltd | Information & communication | 2020 |
| Mind-Reframed Limited | Health & social care | 2015 |
| Mindfulness Harmony Limited | Health & social care | 2023 |
| Mineke Ltd | Professional & scientific | 2023 |
| Minerva Mechanical Ltd | Construction | 2024 |
| Minghui Accountants Limited | Professional & scientific | 2021 |
| Minhas Commerce Limited | Wholesale & retail | 2023 |
| Miniml.Ist Ltd | Administrative & support | 2018 |
| Ministry of Tech Ltd | Information & communication | 2023 |
| Mint Capital Limited | Real estate | 2021 |
| Mint Lane Trading and Services Limited | Wholesale & retail | 2008 |
| Mintprint Global Ltd | Manufacturing | 2024 |
| Miqilin Express Limited | Wholesale & retail | 2020 |
| Mira 2020 Ltd | Wholesale & retail | 2024 |
| Miracles Deco Ltd | Hospitality | 2026 |
| Miranda Gayle Social Work Consultant Limited | Health & social care | 2024 |
| Mirella Ltd | Professional & scientific | 2025 |
| Mirikel Contractors Limited | Administrative & support | 2016 |
| Miriluxe Studios Ltd | Other services | 2025 |
| Mirion Builders Limited | Construction | 2007 |
| Miron Ltd | Transport & logistics | 2019 |
| Mirza Signatures Ltd | Financial services | 2023 |
| Misell Ltd | Wholesale & retail | 2024 |
| Misha Nanny Ltd | Health & social care | 2024 |
| Mishmash Kids Limited | Wholesale & retail | 2024 |
| Miss Ecuador UK Ltd | Health & social care | 2024 |
| Mission Cleaning Ltd | Administrative & support | 2020 |
| Mistry Anand Ltd | Real estate | 2018 |
| Mistry Cakes Limited | Hospitality | 2010 |
| Mistry Mastery Solutions Ltd | Education | 2024 |
| Misty Enterprise Limited | Wholesale & retail | 2026 |
| Mistyrose Limited | Health & social care | 2015 |
| Misu Housing Ltd | Real estate | 2024 |
| Mital Enterprise Limited | Wholesale & retail | 2018 |
| Mital N Ltd | Wholesale & retail | 2023 |
| Mitchellson Ltd | Hospitality | 2022 |
| MJ & SON 360 Ltd | Construction | 2026 |
| MJ Ambition Ltd | Wholesale & retail | 2025 |
| MJ Assani LLP | | 2024 |
| MJ Bathrooms Ltd | Wholesale & retail | 2016 |
| MJ Stay Properties Ltd | Real estate | 2023 |
| MJH Professional Services Ltd | Professional & scientific | 2018 |
| MJH2 Ltd | Real estate | 2025 |
| Mjmhealthleadershipinpractice Limited | Health & social care | 2014 |
| Mjps Property Investments Limited | Real estate | 2025 |
| Mjvrev RN Ltd | Extraterritorial | 2023 |
| MK Deco & Supply Limited | Construction | 2025 |
| MK Fragrance Ltd | Wholesale & retail | 2026 |
| MK Import Europe Limited | Hospitality | 2019 |
| MK Premier Developments Ltd | Construction | 2024 |
| MK2 Properties Ltd | Real estate | 2021 |
| MKC Smiles Limited | Health & social care | 2021 |
| Mkfam Limited | Construction | 2024 |
| MKG Construction Ltd | Construction | 2023 |
| MKG Consultants Ltd | Professional & scientific | 2018 |
| MKG International Ltd | Wholesale & retail | 2022 |
| Mkgp Ltd | Wholesale & retail | 2026 |
| MKI Management Consulting Ltd | Wholesale & retail | 2022 |
| Mkrp UK Limited | Construction | 2025 |
| MKS Consultancy Ltd | Professional & scientific | 2020 |
| MKS Law Ltd | Professional & scientific | 2016 |
| MKV Retail Limited | Wholesale & retail | 2024 |
| Mkva Investments Limited | Administrative & support | 2019 |
| ML Engineers Limited | Construction | 2019 |
| ML Property & Management Ltd | Construction | 2019 |
| MLH Music Limited | Information & communication | 2010 |
| MLI Construct Ltd | Construction | 2021 |
| Mlpc Trading Limited | Wholesale & retail | 2016 |
| MM & JJ Group Services Ltd | Other services | 2022 |
| MM Convenience Ltd | Wholesale & retail | 2025 |
| MM Hairstyle Ltd | Other services | 2025 |
| MM Heravi Properties Ltd | Real estate | 2022 |
| MM Limehouse Ltd | Real estate | 2026 |
| MM Recruitment Consultants Ltd | Professional & scientific | 2024 |
| MM UK Properties Ltd | Real estate | 2022 |
| MMB Global Market Ltd | Wholesale & retail | 2025 |
| MMC Eco Homes Limited | Construction | 2020 |
| Mmct Trading Limited | Hospitality | 2025 |
| MMD Property Investment Limited | Real estate | 2024 |
| MMH Properties Ltd | Construction | 2025 |
| Mmms Properties Ltd | Real estate | 2025 |
| MMS 1 Ltd | Construction | 2023 |
| MMY Construction Ltd | Construction | 2023 |
| MN Asset Managment Ltd | Financial services | 2026 |
| MN Health Ltd | Health & social care | 2026 |
| MN Telecom Limited | Information & communication | 2002 |