| Millbank Property Ltd | Real estate | 2024 |
| Millen Company Holdings Ltd | Real estate | 2026 |
| Millen Homes Land Limited | Real estate | 2022 |
| Millen Homes Limited | Construction | 2009 |
| Millen Land Group Ltd | Construction | 2021 |
| Millenium Sky Tower Ltd | Construction | 2025 |
| Millennial Ecom Ltd | Wholesale & retail | 2025 |
| Millenniam Ltd | Manufacturing | 2024 |
| Millennium Films Limited | Arts & recreation | 1987 |
| Millennium Jewelery Limited | Manufacturing | 2025 |
| Millentao Ltd | Financial services | 2023 |
| Miller Electrical Services Ltd | Other services | 2017 |
| Millerntor Media Limited | Arts & recreation | 2005 |
| Millers Bespoke Bakery Limited | Manufacturing | 1996 |
| Millers Planet Limited | Information & communication | 2025 |
| Millet Food Ltd | Professional & scientific | 2022 |
| Milley London Ltd | Education | 2024 |
| Millford Consultants Ltd | Professional & scientific | 2002 |
| Millhill Supplies Limited | Manufacturing | 1970 |
| Million Bucks Venture Ltd | Administrative & support | 2024 |
| Million Stars London Ltd | Hospitality | 2019 |
| Million's Auto Cars Ltd | Wholesale & retail | 2019 |
| Millionaire Mind Academy Limited | Professional & scientific | 2025 |
| Millon LLP | | 2018 |
| Mills Chody LLP | | 2008 |
| Milo Projects Limited | Construction | 2021 |
| Milo Vision Ltd. | Construction | 2018 |
| Milonixroc Ltd | Professional & scientific | 2026 |
| Milora Limited | Wholesale & retail | 2025 |
| Milton Heritage Limited | Health & social care | 2015 |
| Milvand Holdings Limited | Real estate | 2025 |
| Mima VFX Ltd | Administrative & support | 2012 |
| Mimi's Cake Shop Limited | Manufacturing | 2011 |
| MIN Property Ltd | Real estate | 2024 |
| MIN Solution Ltd | Other services | 2012 |
| Minale Tattersfield & Partners Limited | Arts & recreation | 1964 |
| Minale Tattersfield Design Strategy Group Limited | Professional & scientific | 1989 |
| Minash Ltd | Households | 2023 |
| Minay Properties Ltd | Real estate | 2026 |
| Minbas Ltd | Wholesale & retail | 2021 |
| Mind and Soul World Ltd | Wholesale & retail | 2021 |
| Mind Charge Ltd | Professional & scientific | 2021 |
| Mind First Connections CIC | Education | 2026 |
| Mind First Wellbeing Ltd | Education | 2017 |
| Mind in Harrow | Professional & scientific | 1997 |
| Mind My Soul Collective Ltd | Education | 2023 |
| Mind Over Tech Ltd | Professional & scientific | 2018 |
| Mind Realm Consultation Ltd | Administrative & support | 2023 |
| Mind the Glow Ltd | Wholesale & retail | 2026 |
| Mind Tonic Ltd | Professional & scientific | 2025 |
| Mind-The-Gap Productions Ltd | Information & communication | 1996 |
| Mindexcel IT Solutions Ltd | Information & communication | 2018 |
| Mindful Chaos Gallery Limited | Administrative & support | 2025 |
| Mindfulbase Limited | Health & social care | 2020 |
| Mindgeni Ltd | Administrative & support | 2017 |
| Mindingeye Technologies Limited | Information & communication | 2025 |
| Mindthevision Ltd | Information & communication | 2018 |
| Mine Vital UK Ltd | Other services | 2020 |
| Minerva Contracting Ltd | Construction | 2014 |
| Minerva Elite Ltd | Professional & scientific | 2019 |
| Minerva House Management Limited | Professional & scientific | 2006 |
| Minerva Land Holdings Limited | Financial services | 2025 |
| Ming FAI Engineering Limited | Professional & scientific | 2026 |
| Ming RAY Ltd | Professional & scientific | 2015 |
| Mingle Services Limited | Other services | 2016 |
| Mini Singh UK Ltd | Wholesale & retail | 2023 |
| Minicabbid Svhi Limited | Transport & logistics | 2015 |
| Minien Capital Consulting Ltd | Financial services | 2020 |
| Minimal Carbon Ltd | Wholesale & retail | 2024 |
| Minimal Living Ltd | Wholesale & retail | 2021 |
| Minimalista the Label Ltd | Wholesale & retail | 2021 |
| Minimono UK Retail Services Limited | Wholesale & retail | 2022 |
| Mining 4 Future Limited | Mining & quarrying | 2023 |
| Ministeps Nursery Limited | Administrative & support | 2012 |
| Ministry of Adolescence CIC | Education | 2025 |
| Minocha Associates Ltd | Hospitality | 2018 |
| Mint AC Services Ltd | Real estate | 2025 |
| Mint Green Group Limited | Real estate | 2016 |
| Mint Green Investments Limited | Real estate | 2024 |
| Mint Monee Ltd | Administrative & support | 2013 |
| Mintform Films Ltd | Information & communication | 2026 |
| Minty Care Limited | Professional & scientific | 2024 |
| Miorita Events Limited | Manufacturing | 2025 |
| Miorita Kingsbury Ltd | Hospitality | 2025 |
| MIP Rights Limited | Information & communication | 2016 |
| Mipco Limited | Financial services | 1989 |
| MIR Estate Ltd | Real estate | 2021 |
| Mira Cafe Limited | Hospitality | 2026 |
| Miracle Sound Limited | Arts & recreation | 1978 |
| Miracol Drinks Ltd | Manufacturing | 2025 |
| Mirage Investments Ltd | Financial services | 2006 |
| Miran Properties Limited | Real estate | 2015 |
| Miranda Aluminium Limited | Professional & scientific | 2006 |
| Mirandis Holding Limited | Administrative & support | 2009 |
| Mirauta Ltd | Construction | 2011 |
| Miraway Limited | Households | 1988 |
| Mirco Kitchens Ltd | Manufacturing | 2026 |
| Mirela Radu Ltd | Construction | 2026 |
| Mirevian Ltd | Wholesale & retail | 2026 |
| Miriam's Munchies Limited | Wholesale & retail | 2013 |