| MG Training Ltd | Education | 2026 |
| MGA Sprint Limited | Professional & scientific | 2026 |
| MGH Projects Limited | Construction | 2025 |
| MGP Consultant Ltd | Health & social care | 2024 |
| MH1 Global Limited | Education | 2023 |
| Mhgs Holdings Limited | Financial services | 2025 |
| MHH & Associates Ltd. | Wholesale & retail | 2023 |
| MHS MED Supplies Ltd | Wholesale & retail | 2018 |
| MI Piace Limited | Hospitality | 2018 |
| Mi-Diosventures Limited | Wholesale & retail | 2026 |
| MIA Mente Ltd | Information & communication | 2025 |
| MIA Supplements Ltd | Extraterritorial | 2023 |
| Mianova Ltd | Wholesale & retail | 2025 |
| Miaochun Global Ltd | Wholesale & retail | 2026 |
| Miara Care Services Ltd | Health & social care | 2026 |
| Miark Limited | Real estate | 2009 |
| Miarulla UK Ltd | Wholesale & retail | 2018 |
| Mibaf Consulting Ltd | Information & communication | 2025 |
| Mich, Rich &MEG Ltd | Wholesale & retail | 2024 |
| Michael K Ltd | Transport & logistics | 2022 |
| Michael Mallaby Ltd | Extraterritorial | 2023 |
| Michaels Square Management Limited | Households | 1991 |
| Michmunoz Limited | Health & social care | 2021 |
| Micloria Global Resources Ltd | Hospitality | 2026 |
| Micomast Limited | Wholesale & retail | 2024 |
| Micoms Limited | Professional & scientific | 2007 |
| Micontrac Ltd | Agriculture & fishing | 2012 |
| Micple Ltd | Wholesale & retail | 2025 |
| Microbe Consulting Ltd | Professional & scientific | 2023 |
| Microcide Limited | Manufacturing | 1976 |
| Microsmart Trading Ltd | Wholesale & retail | 2026 |
| MID Consulting Ltd | Financial services | 2009 |
| Midas Securities Ltd | Other services | 2020 |
| Midland Property & Finance Ltd | Real estate | 2018 |
| Midnight Shadow Media Limited | Information & communication | 2025 |
| Midus Communications Limited | Information & communication | 2005 |
| Mieko the Agency Limited | Professional & scientific | 2023 |
| Mieszkania Properties Ltd | Information & communication | 2000 |
| Miguel Santamaria Architects Ltd | Professional & scientific | 2025 |
| Mihail Bozhkov Ltd | Transport & logistics | 2011 |
| Mihido Ltd | Information & communication | 2023 |
| Mike Bessey Coaching Ltd | Other services | 2024 |
| Mike Long Gardens Ltd | Administrative & support | 2013 |
| Mikeipin Limited | Manufacturing | 2025 |
| Miktek Limited | Manufacturing | 1993 |
| Mila Storage Solutions Limited | Construction | 2023 |
| Milbury Scaffolding Ltd | Construction | 2022 |
| Mildenhall Brazilian JIU Jitsu Ltd | Arts & recreation | 2022 |
| Mildenhall Building Supplies Ltd | Wholesale & retail | 2023 |
| Mildenhall Butchers Limited | Hospitality | 2017 |
| Mildenhall Funeral Service Limited | Other services | 2015 |
| Mildenhall Jets Ltd | Arts & recreation | 2023 |
| Mildenhall Skip Hire Limited | Water & waste | 2015 |
| Mildenhall Spice Limited | Hospitality | 2024 |
| Mildenhall Vape Shack Ltd | Wholesale & retail | 2015 |
| Mildens Garage Ltd | Wholesale & retail | 2015 |
| Mile Ventures Limited | Real estate | 2022 |
| Miles Water Engineering Ltd | Construction | 2013 |
| Milex Specialist Cleanroom Services Limited | Manufacturing | 2026 |
| Milfoords Limited | Wholesale & retail | 2017 |
| Mili Mehwar Forum Ltd | Other services | 2021 |
| Milifico Limited | Information & communication | 2012 |
| Military Car Sales Limited | Wholesale & retail | 2006 |
| Milk Club Mildenhall CIC | Health & social care | 2025 |
| Milkshake Games Ltd | Information & communication | 2022 |
| Mill House Homes Limited | Construction | 2007 |
| Mill View (Creeting) Management Company Limited Limited | Households | 2026 |
| Millbrook Systems Ltd | Information & communication | 2023 |
| Millcrush Limited | Extraterritorial | 2015 |
| Millers Yard Management Company Limited | Households | 2004 |
| Millex Contractors Ltd | Construction | 2011 |
| Millimetric Limited | Information & communication | 2017 |
| Million Places Ltd | Information & communication | 2009 |
| Milsom Family Holdings Limited | Financial services | 2024 |
| Milu Limited | Health & social care | 2016 |
| Milz Pillz Ltd | Wholesale & retail | 2016 |
| Mimi Hydration Limited | Manufacturing | 2024 |
| Mimi's Matcha Ltd | Manufacturing | 2026 |
| Mimirra Ltd | Wholesale & retail | 2025 |
| Minco Ltd | Real estate | 2023 |
| Mind to Womb Ltd | Health & social care | 2023 |
| Mindbloom AI Limited | Information & communication | 2023 |
| Mindbridge Group Ltd | Wholesale & retail | 2026 |
| Mindful Nature Ecology Limited | Professional & scientific | 2025 |
| Mindhuntr Ltd | Information & communication | 2025 |
| Mindmix Group Ltd | Financial services | 2026 |
| Mindmix Ltd | Information & communication | 2017 |
| Mindo Help to Build Ltd | Construction | 2023 |
| Mindshift SL Ltd | Extraterritorial | 2024 |
| Mindshiftly Ltd | Wholesale & retail | 2023 |
| Mindvantage Ltd | Health & social care | 2026 |
| Mineralogie Limited | Wholesale & retail | 2022 |
| Minervas Armours Limited | Wholesale & retail | 2001 |
| Minestack Limited | Wholesale & retail | 2022 |
| Ming & Pang Properties (UK) Limited | Real estate | 2018 |
| Minglylink Ltd | Information & communication | 2025 |
| Mini Music Masters Ltd | Education | 2026 |
| Minimal Plates Ltd | Manufacturing | 2023 |
| Minisphere Ltd | Education | 2023 |
| Minnanjey Investments Limited | Real estate | 2015 |