| Milestone Consultancy Limited | Professional & scientific | 2015 |
| Milestone Events (Yorkshire) Ltd | Administrative & support | 2018 |
| Milestone Property Group Ltd | Professional & scientific | 2019 |
| Milestone Solutions Limited | Information & communication | 1997 |
| Milford Contract Furniture Ltd | Manufacturing | 2023 |
| Milford Farm Limited | Agriculture & fishing | 2003 |
| Milford Garage Limited | Wholesale & retail | 2017 |
| Milford Mushrooms Limited | Agriculture & fishing | 2002 |
| Milford Sutcliffe Limited | | 1968 |
| Milim CIC | Education | 2017 |
| Milion Uktr Ltd | Wholesale & retail | 2018 |
| Milk the Children Ltd | Hospitality | 2020 |
| MILKOVICS6 Ltd | Information & communication | 2025 |
| Mill Chase (Alverthorpe Road) Management Company Limited | Households | 2001 |
| Mill Green (Swarcliffe) Management Company Limited | Households | 2008 |
| Mill Kitchen & Bakery Limited | Hospitality | 2022 |
| Mill Portfolio Ltd | Financial services | 2026 |
| Mill Street LED Limited | Wholesale & retail | 2018 |
| Millan Ltd | Information & communication | 2015 |
| Millars Global Assessment Limited | Professional & scientific | 2017 |
| Millbarn Ltd | Construction | 2026 |
| Millbeck Communications Limited | Information & communication | 2002 |
| Millbeck Group Limited | Financial services | 2024 |
| Millbeck Park Management Company Limited | Households | 2005 |
| Millbridge Spinning Company Limited | Manufacturing | 1983 |
| Millcross Consultants Limited | Professional & scientific | 2011 |
| Millennium Gravity Ltd | Professional & scientific | 2025 |
| Miller Prime Ltd | Wholesale & retail | 2024 |
| Miller Wealth Management Limited | Financial services | 2014 |
| Millergate Management Company Limited | Households | 2017 |
| Millers Croft (Ackworth) Management Limited | Households | 2003 |
| Millet China Ltd | Hospitality | 2024 |
| Millfield Court Management Limited | Households | 1999 |
| Millford Plants Limited | Wholesale & retail | 2016 |
| Millhage Consultants Limited | Professional & scientific | 2011 |
| Millhayes Construction Limited | Construction | 2019 |
| Millhouse Furniture & Interiors Limited | Manufacturing | 2008 |
| Millian Capital Group Ltd | Financial services | 2025 |
| Millies Cafe Leeds Limited | Hospitality | 2025 |
| Million Dollar Smile (UK) Ltd | Health & social care | 2026 |
| Million Fashions Ltd | Wholesale & retail | 2025 |
| Millom Water Line Ltd | Real estate | 2022 |
| Millor Consulting Limited | Wholesale & retail | 2025 |
| Millrace Consultancy Ltd | Real estate | 2023 |
| Mills & Thompson Properties Ltd | Real estate | 2019 |
| Mills and Spenceley Limited | Financial services | 2007 |
| Mills Courier Services Ltd | Transport & logistics | 2025 |
| Mills Development North Ltd | Construction | 2023 |
| Mills Property Group North Ltd | Construction | 2025 |
| Mills Security Solutions Limited | Administrative & support | 2018 |
| Milltag Cycling Ltd. | Wholesale & retail | 2011 |
| Milltone Limited | Information & communication | 2024 |
| Millwright (Leeds) Management Company Limited | Real estate | 2023 |
| Millyrose Balloonz Ltd | Other services | 2019 |
| Milmar Holdings Limited | Real estate | 2025 |
| Milner House Ltd | Construction | 2015 |
| Milner Property Estates Limited | Real estate | 1994 |
| Milners Law Group LLP | | 2010 |
| Milo Hire Limited | Information & communication | 2025 |
| Milo Pubs 2025 Limited | Hospitality | 2025 |
| Milo Services Ltd | Transport & logistics | 2025 |
| Milo UK Properties Ltd | Real estate | 2024 |
| Milson Legal Solicitors Limited | Professional & scientific | 2016 |
| Milton & Partners Limited | Professional & scientific | 2001 |
| Milton Keynes Business Centre Limited | Real estate | 2014 |
| Milton Keynes Energy Limited | Construction | 2023 |
| Miluktian Limited | Real estate | 2017 |
| Milutio Ltd | Professional & scientific | 2010 |
| Mimetrik Solutions Limited | Professional & scientific | 2020 |
| Mimisabi Limited | Wholesale & retail | 2021 |
| Mimi’S Haven Hub Ltd | Other services | 2025 |
| Mimshackdesigns Ltd | Wholesale & retail | 2025 |
| Minala Properties Ltd | Real estate | 2024 |
| Minaru Limited | Health & social care | 2016 |
| Minatus Limited | Transport & logistics | 2017 |
| Mincka Ltd | Hospitality | 2021 |
| Minco Products Ltd | Wholesale & retail | 2006 |
| Mincon Carbide Limited | Manufacturing | 2015 |
| Mind Innovation Ltd | Information & communication | 2018 |
| Mind Tools Holdings Ltd | Financial services | 2025 |
| Minda Services Ltd | Wholesale & retail | 2016 |
| Mindbody Breakthrough Ltd | Health & social care | 2017 |
| Mindclimb Ltd | Education | 2026 |
| Mindentra Limited | Information & communication | 2025 |
| Mindful Solutions Global Ltd | Professional & scientific | 2023 |
| Mindful Way Ltd | Real estate | 2024 |
| Mindjourney Ltd | Information & communication | 2026 |
| Mindkonnect Ltd | Other services | 2025 |
| Mindmeld Consultancy Ltd | Information & communication | 2018 |
| Mindperial Limited | Information & communication | 2025 |
| Mindseeds Media Limited | Health & social care | 2018 |
| Mindset Search Ltd | Administrative & support | 2009 |
| Mindsetdrive Ltd | Education | 2025 |
| Mindswing Limited | Education | 2021 |
| Mindtek Ltd | Information & communication | 2025 |
| Mindwell Ltd | Wholesale & retail | 2015 |
| Mineral Cottage Residential Home Limited | Health & social care | 2004 |
| Minerva Evolution Ltd | Professional & scientific | 2026 |
| Minerva House Holdings Limited | Financial services | 2025 |
| Minerva Innovations Ltd | Health & social care | 2015 |