| Lead GEN Associates Ltd | Professional & scientific | 2023 |
| Learning Barn on Manor Farm Limited | Education | 2022 |
| Leather Repair Alterations Limited | Wholesale & retail | 2013 |
| Led-Scape Lighting Ltd | Wholesale & retail | 2021 |
| Leigh Corner Freehold Company Ltd | Households | 2002 |
| Leonidas Productions Limited | Administrative & support | 2025 |
| Letzprotect Ltd | Real estate | 2015 |
| Life Consulting Ltd | Other services | 2019 |
| Lifecloneai Ltd | Information & communication | 2025 |
| Linda Beal Consulting LLP | | 2013 |
| Lisa Davies Promotions Ltd | Arts & recreation | 2015 |
| Little Green HUT Limited | Health & social care | 2023 |
| Lnrdads Limited | Information & communication | 2020 |
| Lobry Couverture Ltd | Construction | 2026 |
| LOBSTER89 Ltd | Wholesale & retail | 2024 |
| London Autocare Centre Ltd | Wholesale & retail | 2026 |
| London Fire Door Solutions Ltd | Construction | 2021 |
| London Magic Devices Ltd | Wholesale & retail | 2026 |
| Long Orchards Kingswood Management Limited | Real estate | 2007 |
| Long Orchards Property Limited | Real estate | 2009 |
| Longevity Swot Ltd | Information & communication | 2025 |
| Looks by Lovegrove Limited | Other services | 2021 |
| Loop Associates Limited | Other services | 2023 |
| Lothian Properties Limited | Real estate | 1990 |
| Lotrop Limited | Construction | 2017 |
| Love Theatre Arts UK LLP | | 2023 |
| LOVE4PADEL Limited | Wholesale & retail | 2025 |
| Lovely Betty Limited | Real estate | 2012 |
| LPA Ltd | Real estate | 2024 |
| LSI Heating Ltd | Manufacturing | 2016 |
| Lucy Taylor Garden Design Ltd | Professional & scientific | 2024 |
| LUV-2-CLN Limited | Other services | 2015 |
| Luxe Beauty Lounge Limited | Other services | 2012 |
| Luxify Ltd | Wholesale & retail | 2026 |
| Lyne Place Management Limited | Households | 1969 |
| Lysitech Ltd | Financial services | 2022 |
| Lywood Close Management Company Limited | Households | 2015 |
| M H Hearingcare Ltd | Health & social care | 2018 |
| Mackenzie Search Ltd | Administrative & support | 2009 |
| Macleane House RTM Company Limited | Households | 2024 |
| Macpherson International Services Limited | Real estate | 1986 |
| Madeline Cranfield Consulting Ltd | Professional & scientific | 2022 |
| Magi Estates Limited | Real estate | 2022 |
| Magic Haven Ltd | Information & communication | 2026 |
| Magna Property Services Ltd | Construction | 2018 |
| Maguire & Weir Trading Ltd | Wholesale & retail | 2020 |
| Mahi Homes Limited | Real estate | 2022 |
| Main Event Scaffold Services Ltd | Construction | 2004 |
| Malling Education Ltd | Real estate | 2025 |
| Managed Outcomes Limited | Professional & scientific | 2026 |
| Manor Farm Experiences Ltd | Agriculture & fishing | 2023 |
| Manor Ridge Estates (Epsom) Limited | Households | 1994 |
| Marc John Willis Construction Ltd | Construction | 2019 |
| Margilockx Ltd | Manufacturing | 2026 |
| Margin Designs Limited | Construction | 1988 |
| Marine & Industrial Products Limited | Wholesale & retail | 2002 |
| Martin Keinch Ltd | Professional & scientific | 2010 |
| Martiniere Limited | Real estate | 2023 |
| Maryland Daycare Ltd | Health & social care | 2026 |
| Masters of Digital Ltd | Wholesale & retail | 2025 |
| Maybury Close Management Limited | Households | 1970 |
| Mayne Construction Ltd | Construction | 2016 |
| Mbcs Group Limited | Information & communication | 2024 |
| Meighan Consulting Limited | Professional & scientific | 2018 |
| Melanie Youles Ltd | Real estate | 2023 |
| Meridian Biotechnologies Limited | Wholesale & retail | 1997 |
| Merland Rise Church Trading Limited | Hospitality | 2014 |
| Merrywood Education Ltd | Education | 2020 |
| Message Properties & Investments Limited | Households | 2025 |
| Mesuteren London Ltd | Hospitality | 2021 |
| Metasphere Limited | Information & communication | 2006 |
| MHK Engineering Ltd | Professional & scientific | 2025 |
| Micprops Limited | Real estate | 2015 |
| Micsolo Management Limited | Professional & scientific | 2014 |
| Micsolo Security Ltd. | Administrative & support | 2014 |
| Ming Yuan International Ltd | Wholesale & retail | 2015 |
| Miralell Holdings Ltd | Real estate | 2018 |
| Mitcham Dwellings Ltd | Real estate | 2024 |
| MJ Consultancy Support Ltd | Hospitality | 2020 |
| MK Global Ecommerce Solutions Ltd | Professional & scientific | 2020 |
| MML Finance Ltd | Health & social care | 2017 |
| MMR Services Ltd | Construction | 2026 |
| Mogstock CIC | Administrative & support | 2022 |
| Moji Studio Ltd | Education | 2022 |
| Monvi Software Solutions Limited | Information & communication | 2019 |
| Moonlit Events Limited | Administrative & support | 2020 |
| Moretti Consulting Ltd | Professional & scientific | 2017 |
| Morgan Gilbert LLP | | 2012 |
| Morgaston Limited | Professional & scientific | 2024 |
| Morningside Consultancy Ltd | Professional & scientific | 2021 |
| Motherland London Limited | Information & communication | 2022 |
| Motr Music Limited | Information & communication | 1987 |
| Mount Garage Auto Repairs Limited | Wholesale & retail | 2019 |
| MPS Kitchens Ltd | Construction | 2017 |
| MR Medical Limited | Health & social care | 2026 |
| MR. BP Ltd | Real estate | 2019 |
| Mrsb Property Limited | Construction | 2010 |
| MS KOI Ltd | Wholesale & retail | 2022 |
| Muhaj Construction Ltd | Construction | 2022 |
| Muka Properties Ltd | Real estate | 2025 |