| Milkshaker Ltd | Wholesale & retail | 2022 |
| Mill Field Forest Gardeners CIC | Health & social care | 2024 |
| Mill Hill (Enderby) Management Company Limited | Real estate | 2016 |
| Mill Hill Brew Co Ltd | Manufacturing | 2021 |
| Mill Hill Stores Ltd | Hospitality | 2017 |
| Mill Street Motors (2000) Limited | Wholesale & retail | 1999 |
| Millenia Fashion Limited | Wholesale & retail | 2025 |
| Millennium Fabrics Limited | Extraterritorial | 1997 |
| Millennium Health Ltd | Health & social care | 2014 |
| Miller Birch Limited | Construction | 2000 |
| Miller Capital Holdings Ltd | Other services | 2026 |
| Miller Compton Maritime Limited | Professional & scientific | 2017 |
| Miller Construction Ltd | Construction | 2025 |
| Miller Fluid Power Limited | Administrative & support | 1988 |
| Miller Group Electrical Ltd | Construction | 2024 |
| Miller Tax Partners LLP | | 2011 |
| Millerplus Investments Limited | Construction | 2015 |
| Millett-Kirkham Commercials Ltd | Wholesale & retail | 2021 |
| Millhum Limited | Construction | 2013 |
| Millican Living Ltd | Real estate | 2026 |
| Millideb Care Limited | Health & social care | 2024 |
| Millie Rose Management Ltd | Real estate | 2017 |
| Millie Victoria Ltd | Manufacturing | 2025 |
| Millionaire Hair Limited | Other services | 2020 |
| Millionzz Ltd | Hospitality | 2024 |
| Millom Pizza Store Ltd | Hospitality | 2024 |
| Millom Stores Ltd | Wholesale & retail | 2023 |
| Mills Ventures Limited | Financial services | 2023 |
| Millstone Eco Limited | Construction | 2025 |
| Millstone Lettings Limited | Real estate | 2018 |
| Millwood Cars Ltd | Wholesale & retail | 2024 |
| Millz Music Limited | Arts & recreation | 2024 |
| Milmega Limited | Manufacturing | 1987 |
| Milmish LLP | | 2025 |
| Milner Property Services Limited | Construction | 2018 |
| Milnthorpe Haulage Ltd | Transport & logistics | 2014 |
| Milo Consulting Limited | Other services | 2014 |
| Milor Mangove Logistics Ltd | Transport & logistics | 2019 |
| Milords International Limited | Wholesale & retail | 1978 |
| Milton Bayer Limited | Professional & scientific | 2014 |
| Milton Bows Ltd | Wholesale & retail | 2025 |
| Milton Gardens Limited | Households | 2011 |
| Milton Larder Limited | Hospitality | 2014 |
| Milton-Bevingtons Ltd | Wholesale & retail | 2017 |
| Milyon Limited | Real estate | 2002 |
| MIM & Co Enterprises UK Ltd | Administrative & support | 2018 |
| Mimi Laser Clinics Limited | Other services | 2012 |
| Mimicoo Ltd | Wholesale & retail | 2026 |
| Mimis Fashions Limited | Manufacturing | 2020 |
| Mimolifa Limited | Real estate | 2015 |
| Mimram Engineering Services Limited | Construction | 2015 |
| Mina Mini Market Ltd | Wholesale & retail | 2025 |
| Mina's Business Limited | Wholesale & retail | 2015 |
| Minarah Academy Ltd | Education | 2020 |
| Minarah Legal Solutions Ltd | Professional & scientific | 2025 |
| Minarah Multiconsulting Limited | Other services | 2012 |
| Mind Aesthetics Ltd | Other services | 2024 |
| Mind Bridge Limited | Professional & scientific | 2025 |
| Mind Craft AI Ltd | Information & communication | 2025 |
| Mind Friendly Consulting Ltd | Information & communication | 2023 |
| Mind the Grease Games Ltd | Information & communication | 2025 |
| Mind Well Psychiatry Ltd | Health & social care | 2024 |
| Minden Limited | Wholesale & retail | 1973 |
| Mindera Code Academy UK Limited | Education | 2021 |
| Mindera Consulting Limited | Professional & scientific | 2020 |
| Mindera Education Limited | Education | 2022 |
| Mindera Gaming Company Limited | Information & communication | 2019 |
| Mindera Group Limited | Information & communication | 2020 |
| Mindera Holdings Limited | Information & communication | 2017 |
| Mindera UK Foundation | Education | 2024 |
| Mindera UK Limited | Information & communication | 2016 |
| Mindflow Hypnotherapy Ltd | Health & social care | 2023 |
| Mindful Champs Limited | Wholesale & retail | 2016 |
| Mindful Marks Limited | Wholesale & retail | 2025 |
| Mindful Minerals Ltd | Wholesale & retail | 2024 |
| Mindful Thoughts PVT Ltd | Hospitality | 2023 |
| Mindful Warriors Limited | Education | 2018 |
| Mindfullfoodfitness Ltd | Health & social care | 2022 |
| Mindmap Creative Limited | Hospitality | 2021 |
| Mindnest Limited | Health & social care | 2025 |
| Minds Crafts Consultations Ltd | Health & social care | 2024 |
| Mindset Rewired Coaching Ltd | Other services | 2025 |
| Mindset Solutions International Ltd | Education | 2020 |
| Mindspace Global Ltd | Health & social care | 2023 |
| Mine Industries Ltd | Manufacturing | 2025 |
| Minecraft Projects Ltd | Real estate | 2025 |
| Minefield Consulting Ltd | Professional & scientific | 2024 |
| Minegali Limited | Real estate | 2023 |
| Mineral Surveying Services Ltd | Administrative & support | 2007 |
| Minerva Fire Limited | Professional & scientific | 1996 |
| Minerva Simulators Limited | Manufacturing | 2024 |
| Minerva Stratagem Consulting Limited | Professional & scientific | 2018 |
| Minerva Supported Living (Property Management) Ltd | Real estate | 2026 |
| Minerva Supported Living Ltd | Real estate | 2017 |
| Minerva Tuition Ltd | Education | 2026 |
| Minesh Mehta Limited | Real estate | 2025 |
| Mingo Cleaning Services Limited | Administrative & support | 2023 |
| Mini Adventures (Market Harborough) Ltd | Education | 2018 |
| Mini Bikers CIC | Education | 2025 |
| Mini Galo Store Ltd | Wholesale & retail | 2024 |