| London Auto Club Ltd | Wholesale & retail | 2021 |
| London Brothers Ltd | Manufacturing | 2017 |
| London Home Repairs Ltd | Construction | 2024 |
| London IP Exchange Limited | Information & communication | 2012 |
| London Spine Ltd | Health & social care | 2021 |
| London Tamil Ventures Limited | Real estate | 2026 |
| Londonpack Limited | Wholesale & retail | 2020 |
| Long Lost Clothes Ltd | Wholesale & retail | 2024 |
| Look at ME Ltd | Other services | 2014 |
| Lookhouse Ltd | Construction | 2023 |
| Loop ERA Ltd | Information & communication | 2026 |
| Loopey Property Management Ltd | Professional & scientific | 2003 |
| Lost Avalon Publishing Limited | Administrative & support | 2025 |
| Lotus Ventureprises Limited | Professional & scientific | 2018 |
| Lotus Visual Productions Ltd | Information & communication | 2019 |
| Loudwater Close 1960 Limited | Extraterritorial | 2014 |
| Luca Osborne Limited | Information & communication | 2025 |
| Lucas & Williams Property Group Limited | Real estate | 2025 |
| Lucien&Brown Limited | Manufacturing | 2005 |
| Lucky Air Conditioning & Heat Pumps Ltd | Construction | 2026 |
| Luff & Padgett Limited | Construction | 2000 |
| Lukenest Lettings Ltd | Real estate | 2025 |
| Luna Baai Limited | Wholesale & retail | 2019 |
| Lushwell Co Ltd | Wholesale & retail | 2025 |
| Luvbiltong Ltd | Manufacturing | 2021 |
| Luxel Ltd | Wholesale & retail | 2025 |
| Luxury Coaches London Limited | Transport & logistics | 2026 |
| Luxury Minibus Travel Limited | Transport & logistics | 2014 |
| LV Estate Agents Limited | Real estate | 2016 |
| LXL London Ltd | Wholesale & retail | 2025 |
| M&S Home Management Ltd | Construction | 2024 |
| M.Wagner Limited | Professional & scientific | 2017 |
| MA Investments and Holdings Ltd | Financial services | 2025 |
| Maasr Ltd | Information & communication | 2017 |
| Macro Mortgages Limited | Financial services | 2022 |
| Macroplus Financials Ltd | Financial services | 2025 |
| Madhav Enterprise Limited | Wholesale & retail | 2022 |
| Mafhk Limited | Hospitality | 2026 |
| MAG Construction (Sunbury) Limited | Construction | 2013 |
| Magic Elephant Ltd | Education | 2021 |
| Magiq Limited | Information & communication | 2009 |
| Main Onsight Security Ltd | Financial services | 2025 |
| Maitri Community Limited | Education | 2024 |
| Majconsult Ltd | Information & communication | 2021 |
| Majka Fitnat Ltd | Wholesale & retail | 2021 |
| Maktz Limited | Hospitality | 2015 |
| Maliks Bros Ltd | Hospitality | 2026 |
| MANAGEMENT4PROPERTY Limited | Real estate | 2010 |
| Manveen's Store Ltd | Wholesale & retail | 2024 |
| Marbel Transport Limited | Transport & logistics | 2014 |
| March Decor Ltd | Construction | 2008 |
| Markarproperty Limited | Real estate | 2021 |
| Maroon Properties Limited | Real estate | 2018 |
| Marval Transport Solutions Ltd | Transport & logistics | 2021 |
| Masrays Technical Services Ltd | Manufacturing | 2025 |
| Matt-Finish Ltd | Construction | 2024 |
| Matthews Bros.(Ashford)Limited | Real estate | 1961 |
| Maurice Ward & Co. UK Limited | Transport & logistics | 2002 |
| Maurice Ward Networks UK Ltd | Transport & logistics | 2015 |
| Maydave Ltd | Hospitality | 2021 |
| Mayfield (Eccleston Park) Management Ltd | Real estate | 2024 |
| Mbros Holdings Ltd | Financial services | 2021 |
| Mcconnell Ventures Ltd | Administrative & support | 2026 |
| MCP Land Asset Management 1 Ltd | Real estate | 2023 |
| MDM Realty Limited | Real estate | 2026 |
| MDM Ventures Limited | Financial services | 2026 |
| MDT Consultancy Limited | Professional & scientific | 2013 |
| Mead Contracting Developments Limited | Construction | 2008 |
| Mead Investments Limited | Real estate | 2003 |
| Meadowlands New Homes Ltd | Extraterritorial | 2013 |
| Medical Practice Support Ltd | Administrative & support | 2025 |
| Medikey Health Consultancy Limited | Administrative & support | 2019 |
| Medriche Ltd | Health & social care | 2023 |
| Melbury Construction Ltd | Construction | 2014 |
| Menaj Investments Limited | Construction | 2023 |
| Mercer Rigging Ltd | Information & communication | 2019 |
| Metatalent.Ai Ltd | Information & communication | 2020 |
| Metro Apartments Management Company Limited | Households | 2005 |
| MG Ivanov Limited | Manufacturing | 2026 |
| MGS Business Services Limited | Professional & scientific | 2013 |
| MIA 168 Ltd | Hospitality | 2025 |
| Middle East Book Review Limited | Information & communication | 2016 |
| Mili Builders Ltd | Construction | 2023 |
| Military History Tours Limited | Administrative & support | 2010 |
| Minalima Ltd | Professional & scientific | 2009 |
| Minka HUS Ltd | Real estate | 2023 |
| MJM Consulting Services Ltd | Administrative & support | 2023 |
| MJT Holdings Limited | Real estate | 2025 |
| MK3 Services Ltd | Construction | 2024 |
| Mmcor Limited | Professional & scientific | 2021 |
| MMJ Appointments Ltd | Professional & scientific | 2024 |
| Modaline Global Ltd | Wholesale & retail | 2025 |
| Mona & Shahbaz Properties Ltd | Real estate | 2020 |
| Monkey Puzzle Holdings Limited | Administrative & support | 2015 |
| Montford Place Residents Management Company Limited | Households | 2013 |
| Monya Ltd | Wholesale & retail | 2024 |
| Moodfree Limited | Households | 1988 |
| Moore Agile Delivery Limited | Information & communication | 2018 |
| MORLEY51 Limited | Real estate | 2017 |
| MOT Centre Heston Ltd | Wholesale & retail | 2017 |