| Milestone Driving School Limited | Education | 2021 |
| Millennium Carriage Services Limited | Wholesale & retail | 2010 |
| Millennium Food Limited | Hospitality | 2025 |
| Miller and Mason Brickwork Company Limited | Construction | 2016 |
| Millimetre Interiors Ltd | Construction | 2020 |
| Million Barrels Ltd | Mining & quarrying | 2020 |
| Milton Close 1974 Limited | Extraterritorial | 2014 |
| MIM Commerce Ltd | Wholesale & retail | 2024 |
| MIN Enterprises Limited | Information & communication | 2015 |
| Minaxi Ventures Limited | Wholesale & retail | 2002 |
| Mindlynk Ltd | Administrative & support | 2025 |
| Mindup and Tech Limited | Information & communication | 2022 |
| Mineet UK Limited | Wholesale & retail | 2016 |
| Minerals Paradise Ltd | Wholesale & retail | 2026 |
| Mingalar Limited | Transport & logistics | 2023 |
| Mini Milling Ltd | Manufacturing | 2019 |
| Mini-Mx Limited | Construction | 2011 |
| Minj Limited | Real estate | 2021 |
| Mintu Home Improvements Ltd | Construction | 2019 |
| Minyah Ltd | Arts & recreation | 2015 |
| Mira Private Ltd | Wholesale & retail | 2024 |
| Miracle Greens Ltd | Manufacturing | 2018 |
| Miracle Hair and Beauty Ltd | Other services | 2024 |
| Mirage Carpentry Ltd | Manufacturing | 2019 |
| Miragon Investments Limited | Professional & scientific | 2018 |
| Miriste Trans Ltd | Transport & logistics | 2025 |
| Mirpur Electrical and Electronics Trading Limited | Wholesale & retail | 2024 |
| Mirror Invest Ltd | Real estate | 2021 |
| Mirza Holdings Ltd | Real estate | 2019 |
| Mirza Properties Ltd | Real estate | 2019 |
| Missandei Limited | Information & communication | 2023 |
| Missile Project Limited | Transport & logistics | 2021 |
| Mitchell Scaffolding UK Ltd | Construction | 2024 |
| Mixaro Limited | Wholesale & retail | 2025 |
| Miyabi Spa Ltd | Other services | 2025 |
| MJ Investments & Developments Ltd | Real estate | 2020 |
| MJ Nexus Limited | Wholesale & retail | 2026 |
| MJ Noble Transport Ltd | Transport & logistics | 2025 |
| MJN Karate Limited | Arts & recreation | 2024 |
| MJO Support Services Ltd | Professional & scientific | 2015 |
| MK &S Construction Limited | Construction | 2019 |
| MK Carpet & Flooring Limited | Wholesale & retail | 2025 |
| MK Design Homes Ltd | Construction | 2023 |
| MK Digital Consulting Ltd | Information & communication | 2026 |
| MK Emerald Limited | Construction | 2026 |
| MK Food Stores Ltd | Wholesale & retail | 2013 |
| MK Home Interior Design Ltd | Other services | 2025 |
| MK Motors (Hayes) Ltd | Other services | 2021 |
| MK Parts Supplier Ltd | Wholesale & retail | 2022 |
| MK Removal Service Ltd | Transport & logistics | 2025 |
| MK Sihra Properties Ltd | Transport & logistics | 2018 |
| MK Southall Ltd | Hospitality | 2025 |
| MK SPV Ltd | Real estate | 2021 |
| MK2 Construction Ltd | Manufacturing | 2022 |
| MKK Stores Ltd | Wholesale & retail | 2025 |
| Mkri Construction Limited | Construction | 2007 |
| MKS Food & Wine Limited | Wholesale & retail | 2009 |
| ML Contracts Ltd | Construction | 2025 |
| ML Residences Ltd | Real estate | 2023 |
| MLI Refurb Limited | Construction | 2015 |
| Mlvv Carpenters Ltd | Construction | 2024 |
| MM Bros Construction Ltd | Construction | 2022 |
| MM DON Ltd | Other services | 2017 |
| MM JJ Food and Wine Ltd | Wholesale & retail | 2026 |
| MM Links Ltd | Manufacturing | 2020 |
| MM Roofing and Building Ltd | Construction | 2025 |
| MMD Consultancy Ltd | Administrative & support | 2017 |
| Mmhv UK Limited | Wholesale & retail | 2014 |
| Mmkz Courier Limited | Transport & logistics | 2023 |
| MMS Transport Ltd | Transport & logistics | 2025 |
| MMV Construction Ltd | Construction | 2023 |
| MMW Duncan Limited | Construction | 2026 |
| Mmwoodpecker Ltd | Construction | 2023 |
| MN Retail Ltd | Wholesale & retail | 2025 |
| MN Top Ltd | Construction | 2025 |
| MNA & Sons London Properties Ltd | Real estate | 2025 |
| Mnbs Smart Ltd | Transport & logistics | 2021 |
| Mnds Ltd | Construction | 2025 |
| MNJ Food & Wines Ltd | Wholesale & retail | 2015 |
| MNM Handyman Services Ltd | Construction | 2026 |
| MNS Homes Limited | Real estate | 2023 |
| MNS Weini Properties Ltd | Real estate | 2022 |
| MNS3 Ltd | Construction | 2025 |
| Moana Poke Bowls Ltd | Hospitality | 2024 |
| Mobhvi Limited | Manufacturing | 2025 |
| Mobile Fade Box Ltd | Other services | 2025 |
| Mobile Fit Tyres Limited | Wholesale & retail | 2025 |
| Mobile Hub Ltd | Other services | 2011 |
| Mobile Touch Woking Ltd | Wholesale & retail | 2025 |
| Mobile Tyre RESCUE24/7 Ltd | Wholesale & retail | 2025 |
| Mobile Wash Ltd | Other services | 2021 |
| Mobilise Group Limited | Wholesale & retail | 2017 |
| Mobyco Ltd | Wholesale & retail | 2024 |
| Mobyco Oxford Ltd | Wholesale & retail | 2025 |
| Moconstructs Ltd | Professional & scientific | 2020 |
| Modec International Limited | Construction | 2021 |
| Modest Living UK Limited | Real estate | 2025 |
| Moeen & Co. Solicitors Ltd | Professional & scientific | 2023 |
| Moeen Khan Ltd | Professional & scientific | 2018 |
| Moga Haulage Limited | Transport & logistics | 2018 |