| Mehar Retail Ltd | Wholesale & retail | 2013 |
| Mehar's Transport Ltd | Transport & logistics | 2025 |
| Mehla Construction Ltd | Construction | 2025 |
| Mehlaz Ltd | Wholesale & retail | 2026 |
| Mehma Ltd | Professional & scientific | 2022 |
| Mehwish Solutions Ltd | Administrative & support | 2025 |
| Meilustre & Medical Limited | Health & social care | 2025 |
| Meilydoll Ltd | Wholesale & retail | 2022 |
| Meister Assets Ltd | Real estate | 2023 |
| Meister Real Estate Ltd | Real estate | 2019 |
| Meka Travel Ltd | Professional & scientific | 2015 |
| MEL Games Limited | Arts & recreation | 2023 |
| Melbourne Court Displays Ltd | Professional & scientific | 2019 |
| Melinasco Limited | Professional & scientific | 2022 |
| MELIORA24 Ltd | Wholesale & retail | 2022 |
| Mellida Family Transport Ltd | Transport & logistics | 2025 |
| Melot Co. Ltd | Health & social care | 2020 |
| Melting Fire Limited | Manufacturing | 2023 |
| Melton Developments Ltd | Real estate | 2023 |
| Melvacalashes Ltd | Other services | 2023 |
| Mentage Ltd | Education | 2024 |
| Menue 21 Ltd | Hospitality | 2025 |
| Meraki Thai Therapy Ltd | Other services | 2022 |
| Merakize Ltd | Professional & scientific | 2024 |
| Merbani Grove Heating and Plumbing Limited | Wholesale & retail | 2019 |
| Mercari Ventures Ltd | Wholesale & retail | 2025 |
| Mercy MUS Limited | Health & social care | 2021 |
| Meri Marzi Restaurant Limited | Hospitality | 2024 |
| Meridian Global Services (UK) Ltd | Wholesale & retail | 2025 |
| Meridian Hotel Holdings Limited | Professional & scientific | 2020 |
| Meridian Hotel Operations Limited | Hospitality | 2012 |
| Meridian Integrated Technologies UK Ltd | Administrative & support | 2024 |
| Meridian Pier Limited | Real estate | 1997 |
| Meridian Residential Developments Limited | Real estate | 2012 |
| Meridiandrive Limited | Other services | 2016 |
| Merriment & Love Limited | Other services | 2009 |
| MES Design Ltd | Professional & scientific | 2019 |
| MES Solutions Limited | Information & communication | 2012 |
| Metalgod Ltd | Manufacturing | 2015 |
| Metalonics Limited | Manufacturing | 2021 |
| Metanoia Fostering Ltd | Health & social care | 2025 |
| Metapharma Ltd | Health & social care | 2015 |
| Metro Business Ltd | Administrative & support | 2015 |
| Metro Convenience Limited | Wholesale & retail | 2017 |
| Metro Investments London Limited | Real estate | 2014 |
| Metrobuild 04 Ltd | Construction | 2026 |
| Mexbio Ltd | Professional & scientific | 2025 |
| Mexem Ltd | Information & communication | 2016 |
| Meyon Estates and Developments Limited | Construction | 2023 |
| Meyvin Solutions Ltd | Information & communication | 2012 |
| Mezza ME Ltd | Hospitality | 2025 |
| MG AG Ltd | Other services | 2016 |
| MG Construction Builders Ltd | Construction | 2025 |
| MG Tax Advice Ltd | Professional & scientific | 2018 |
| MG789 Limited | Real estate | 2025 |
| MGC Investments LLP | | 2024 |
| Mgke Limited | Information & communication | 2025 |
| MGM Traderz Ltd | Manufacturing | 2024 |
| MH UK Investment Ltd | Real estate | 2021 |
| MH Utilities Limited | Construction | 2019 |
| Mhassan Inc Ltd | Professional & scientific | 2024 |
| MHI London Ltd | Real estate | 2018 |
| MHL Care Limited | Health & social care | 2018 |
| Mhonlineuk Limited | Wholesale & retail | 2016 |
| MHR Transport Ltd | Transport & logistics | 2025 |
| MHY Trade Cars Ltd | Wholesale & retail | 2024 |
| MI- Ecommerce Business Ltd | Wholesale & retail | 2024 |
| Mi-V London Limited | Health & social care | 2019 |
| Miami International Limited | Wholesale & retail | 2020 |
| Miami Investments Limited | Real estate | 2023 |
| Mian Saif Limited | Manufacturing | 2024 |
| Michalak Construction Ltd | Construction | 2018 |
| Micro MAX Communications Limited | Wholesale & retail | 2012 |
| Micronet Electronics Ltd | Other services | 2018 |
| Microtronix Ltd | Manufacturing | 2004 |
| Midal Cables International Ltd. | Wholesale & retail | 1998 |
| Middle East Trader Ltd | Wholesale & retail | 2022 |
| Middle Eastern Food Ltd | Hospitality | 2024 |
| Middlesex Care Partnership Ltd | Health & social care | 2022 |
| Middlesex Electrical Services Ltd | Construction | 2018 |
| Middlesex Food Safety Ltd | Professional & scientific | 2016 |
| Middlesex Pride CIC | Other services | 2023 |
| Middlesex Property and Facilities Management Limited | Real estate | 2014 |
| Middlesex Scaffolding Ltd | Construction | 2025 |
| Middlesex Schools Cricket Limited | Education | 2022 |
| Middlesex Supplies Ltd | Wholesale & retail | 2021 |
| Midhus Investment Ltd | Real estate | 2002 |
| Midland Technology Limited | Information & communication | 2016 |
| Midpoint EWS Ltd | Health & social care | 2025 |
| Mighty Fort Foods Limited | Hospitality | 2024 |
| Migration Square London Limited | Information & communication | 2023 |
| Mihaf Limited | Real estate | 2021 |
| Mikajam Ltd | Wholesale & retail | 2025 |
| Mike’S Executive Cars Limited | Transport & logistics | 2026 |
| Milan Superstores Limited | Wholesale & retail | 2014 |
| Milestone Motors London Ltd | Wholesale & retail | 2023 |
| Milestone Pro Ltd | Professional & scientific | 2023 |
| Militant Entertainment Ltd | Information & communication | 2019 |
| Mille Rose Limited | Transport & logistics | 2018 |
| Millenium Assets Holding Ltd | Financial services | 2025 |