| Midas Bubble Ltd | Wholesale & retail | 2019 |
| Midas-B Ltd | Professional & scientific | 2013 |
| Middle East Online Limited | Information & communication | 2001 |
| Middle Note Limited | Arts & recreation | 2017 |
| Midelatory Consulting Limited | Professional & scientific | 2016 |
| Midnights Health Ltd | Health & social care | 2024 |
| Mielen Ltd | Health & social care | 2023 |
| Miem Limited | Hospitality | 2023 |
| Mightel Technologies Ltd | Information & communication | 2012 |
| Mikali Limited | Real estate | 2019 |
| Mikdash Properties Ltd | Real estate | 2024 |
| Mikesh Group Limited | Construction | 2016 |
| Mikford Builders Limited | Construction | 2020 |
| Mikhael & Raphael Enterprises Ltd | Wholesale & retail | 2024 |
| Miki Home Limited | Real estate | 2019 |
| Milan Memorials Ltd | Administrative & support | 2019 |
| Mile-X Projects Ltd. | Administrative & support | 2020 |
| Mile-X Properties & Investments Limited | Real estate | 2018 |
| Milen Service Ltd | Transport & logistics | 2011 |
| Milesian Londain Ltd | Professional & scientific | 2015 |
| Milestone (Crystal Palace) Management Limited | Households | 2006 |
| Milestone Chambers Ltd | Professional & scientific | 2021 |
| Milestone Garage (Dartford) Limited | Wholesale & retail | 2003 |
| Milestone Kebab Limited | Hospitality | 2013 |
| Milestones Day Nursery Limited | Education | 2024 |
| Milk Moments Ltd | Health & social care | 2024 |
| Milktree Gelato Limited | Manufacturing | 2020 |
| Mill House Gardens (Dartford) Management Limited | Households | 1997 |
| Mill ROW Catering Co Ltd | Hospitality | 2024 |
| Mill Studio Pilates Limited | Arts & recreation | 2025 |
| Millen Court Residents Company Ltd | Households | 2004 |
| Millen Estates Limited | Real estate | 2002 |
| Millers Office Furniture Ltd | Construction | 2024 |
| Millie & Maisie Ltd | Hospitality | 2022 |
| Millie Jones Hair Farnham Ltd | Other services | 2026 |
| Millie Jones Limited | Other services | 2014 |
| Millie Jones Odiham Ltd | Other services | 2024 |
| Mills Mechanical Limited | Construction | 2022 |
| Milly’S Cake House Limited | Manufacturing | 2024 |
| Milos Jewellery Limited | Manufacturing | 2025 |
| Mimi Ríos Group Ltd | Education | 2026 |
| Mimma Aesthetics Ltd | Wholesale & retail | 2020 |
| Mimmabux Investment Holdings Limited | Financial services | 2011 |
| Mindtech Solutions Limited | Professional & scientific | 2012 |
| Minerva SAI Limited | Information & communication | 2014 |
| Ming TAK Inn Ltd | Hospitality | 2023 |
| Mingso Ltd | Professional & scientific | 2025 |
| Mini Coach Travel Limited | Other services | 2014 |
| Minis by Missy Ltd | Wholesale & retail | 2025 |
| Mint Art Gallery Limited | Arts & recreation | 2011 |
| Minty Cloud Limited | Information & communication | 2012 |
| Mira Timber Products Ltd | Wholesale & retail | 2008 |
| Miracle Consulting Limited | Information & communication | 2014 |
| Mirakle Productions Ltd | Administrative & support | 2017 |
| Miramiche Limited | Education | 2026 |
| Miss Party Limited | Wholesale & retail | 2011 |
| Mission Healthcare UK Ltd. | Health & social care | 2024 |
| Mission Produce UK Limited | Manufacturing | 2021 |
| Mister Lifter Ltd | Construction | 2023 |
| Mitre Brickwork Essex Ltd | Construction | 2022 |
| MJ Childcare Services Ltd | Real estate | 2019 |
| MJ Consultancy London Ltd | Administrative & support | 2024 |
| MJ Padel Services Ltd | Information & communication | 2024 |
| Mjade Solutions Limited | Information & communication | 2020 |
| MJC Network Solutions Limited | Information & communication | 2003 |
| MJD Group Facilities Ltd | Transport & logistics | 2026 |
| MJJ IT Consultancy Ltd | Professional & scientific | 2020 |
| MJP Jewellers Limited | Administrative & support | 2014 |
| MJR and Sons Commercial Services Ltd | Wholesale & retail | 2024 |
| MJV GAS & Heating Ltd | Construction | 2016 |
| MK 1 Stone Restoration Ltd | Manufacturing | 2020 |
| MK Lifestyle Properties Ltd | Real estate | 2020 |
| MK Motors South Ltd | Wholesale & retail | 2009 |
| MK Properties (Kent) Ltd | Real estate | 2024 |
| MK Renovations Ltd | Construction | 2022 |
| MK Software Solutions Ltd | Information & communication | 2017 |
| Mkaa Properties Ltd | Real estate | 2022 |
| Mkaa Retail Ltd | Wholesale & retail | 2024 |
| MKJ Consultancy South East Limited | Administrative & support | 2019 |
| MKO Property Management Ltd | Real estate | 2026 |
| MKS Global Trading Ltd | Wholesale & retail | 2005 |
| MLH Rising Ltd | Real estate | 2022 |
| MLJ Business Solutions Ltd | Information & communication | 2025 |
| MLN Property Services Limited | Real estate | 2008 |
| MLN Services Ltd | Professional & scientific | 2025 |
| Mlowen Consulting Ltd | Professional & scientific | 2020 |
| MM Music Worldwide Ltd | Arts & recreation | 2021 |
| MMB Recruitment Ltd | Administrative & support | 2026 |
| MMC Transport Ltd | Transport & logistics | 2018 |
| MMG Publishing Limited | Information & communication | 2005 |
| Mmgb Management Company Limited | Households | 2020 |
| Mmsj Consultancy Services Limited | Information & communication | 2019 |
| MN London Limited | Wholesale & retail | 2024 |
| Mnas Distribution Ltd | Wholesale & retail | 2026 |
| MNE Signalling Rail Consulting Limited | Construction | 2025 |
| MNM Property Investors Ltd | Real estate | 2020 |
| MNN Academy Ltd | Wholesale & retail | 2025 |
| MNS Customs Limited | Transport & logistics | 2023 |
| MO Sounds and Events Limited | Information & communication | 2017 |
| Mo's Business Ltd | Manufacturing | 2023 |